Super Small Animals


Super Small Animals

Biologist Patrick Aryee explores the fascinating secrets behind what makes small animals successful, from a little lemur to a tiny armadillo.


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Transcript


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The natural world is full of fantastically small animals.

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Hello! Where are you going?

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And I mean REALLY small.

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Some you'll recognise because millions of us watch them online.

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Some are rare and unusual...

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..and others look like big animals that have shrunk in the wash.

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Despite initial appearances,

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these animals aren't the underdogs you might think they are.

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In fact, new science is revealing that these small-scale superheroes

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are perfectly adapted to deal with the challenges

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of the big, wide world in their own unique ways.

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I'm Patrick Aryee and as a biologist,

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I want to find out what makes these super small creatures

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some of the most successful animals on the planet.

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HE CHUCKLES

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That is brilliant! This is the first time I've seen anything like this.

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We're going to travel the world to meet the leading experts

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on these incredible creatures and discover the secrets

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behind these pint-sized superstars,

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revealing the huge benefits that being small can bring,

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as well as the challenges that small creatures face

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and the ingenious ways they overcome them.

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Look at that.

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And I'll also show you how some miniature animals

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punch way above their weight.

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They've all turned being small into a HUGE advantage.

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And we're going to find out why.

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This is a leaf chameleon.

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It lives in northern Madagascar

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and as its name suggests,

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it goes about the leaf litter eating tiny insects.

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Weighing less than a quarter of a gram, it's minuscule

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and one of the smallest lizards in the world.

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Pound for pound, they are 3,500 times smaller than this guy.

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The Parson's chameleon.

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The weight difference between them

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is the same between me and ten elephants.

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I can't get them too close together

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because the Parson's chameleon's prey

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is bigger than the leaf chameleon.

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But despite the size difference,

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these two are remarkably similar.

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They both have all the classic chameleon characteristics...

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..independently moving, rotating eyes...

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..specialised gripping feet

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with toes that point forward and backwards...

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..and a super-powered tongue that shoots out and suckers prey.

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The leaf chameleon has all the same complex attributes,

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just miniaturised.

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But why?

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Nothing ever happens by accident in nature.

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This guy obviously wouldn't be this size if it didn't make sense.

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If anything, it means that it's easier to hide,

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it needs less food and less space.

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So, by being small,

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this chameleon has overcome some of life's biggest challenges -

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finding food, keeping out of danger

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and finding its own space in this big, wide world.

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And it's not alone.

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Animals all over the globe are using their small size

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to solve life's problems.

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And one of the biggest problems

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is finding enough food in a fiercely competitive world.

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The island of Madagascar,

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home to over 100 species of lemur.

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Just like us, they're primates,

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and they come in all different shapes,

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colours and sizes.

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But I'm here to meet the smallest.

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Mouse lemurs.

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They're barely the size of an apple.

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Now, this guy probably weighs about 70g

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which is surprising when you think that the largest primates,

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the gorilla, weighs over 3,000 times as much.

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And even the largest lemur, the indri,

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is still over 100 times this lemur's weight.

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Despite this, when it comes to a special source of food,

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they come out on top.

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All lemurs eat fruits, seeds and leaves.

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And with so much competition for the tastiest treats,

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you'd think the tiny mouse lemur would be at the back of the queue.

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But this little lemur uses its size to its advantage.

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Whilst other lemurs are just too heavy...

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..because they're small,

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mouse lemurs can head straight for the ends

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of the highest, flimsiest branches.

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And the special food they're after?

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Flowers.

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Rich in sugars, they make one of the best meals

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and these tiny lemurs get to them with ease.

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Their larger, heavier cousins

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have to compete for food on bigger branches...

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..but mouse lemurs avoid the competition

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by reaching the unreachable.

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Lemurs aren't the only ones using their size to secure a snack.

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On the other side of the globe,

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in the cloud forests of Ecuador,

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another tiny animal is muscling in on its next meal.

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Hummingbirds are the smallest birds on the planet.

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They are incredibly appealing

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and when it comes to viral videos,

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they are an internet sensation.

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The smallest are the same size as a large bee.

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And take a look at how tiny their nests are.

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Hummingbirds are well-known for the incredible speed

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with which they move their wings.

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They can beat them up to 15 times a second.

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But it uses a huge amount of energy, so they feed on sugar-rich nectar.

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And because they need to consume a lot of calories,

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access to the best flowers is worth fighting for.

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But in this world of tiny birds,

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size still matters and it turns out that being even smaller

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is even better.

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The booted racket-tail is tiny, no bigger than your little finger.

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So, while the big boys are fighting over the flowers,

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the smaller, more agile racket-tail can sneak in...

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..feed and fly off before being spotted by the bigger birds.

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A cheeky move proving that being the smallest of the small

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can sometimes offer big payoffs in the fight for food.

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Going unseen is another huge advantage of being miniature.

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And it's something that my next super small animal

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has taken to the extreme.

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The ocean is a perilous place for little creatures.

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They're easy pickings for hundreds of larger predators.

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In fact, less than 1% of fish reach maturity.

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So, to survive, you need a strategy.

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On the reefs of Australia and Southeast Asia,

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a super-small creature,

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living in this sea fan coral,

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has just that.

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But first, we have to find it.

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The pygmy seahorse,

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the smallest of its kind.

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So small they could fit on your fingernail...

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or the end of a pencil.

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Truly tiny and perfectly camouflaged to their coral home.

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Which makes these little seahorses almost impossible to spot.

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In fact, they were unknown to science until 1969

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when they were discovered completely by accident.

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Nobody knew they existed until one of the corals was collected

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and when they brought it up to look at the coral,

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they saw something small and moving on it.

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And when they looked closely, they realised it was a tiny seahorse

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that looked exactly like the arms of the coral.

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These little seahorses are actually born smooth and brown.

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But as they develop, they transform to match the colour and texture

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of the sea fan they land on,

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regardless of the colour of their parents.

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Within 24 hours,

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they would clearly change colour

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and change in characteristics to match that coral,

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and that was a pretty amazing thing to see happen.

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These miniature marvels then spend their entire life

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on that one piece of coral,

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which can be over a metre tall and wide.

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When you're that small,

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that's plenty of space to make a home.

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The pygmy seahorse has evolved to be so small to take advantage

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of a piece of real estate

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that nobody else is really taking advantage of.

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In fact, there could be up to 28 pairs of seahorses

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living on one sea fan...

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..hidden in plain sight.

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But even a secretive seahorse needs to eat.

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The pygmy seahorse is a predatory fish,

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just like the massive great white shark.

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Now, you might think of the shark as having it better,

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but they have to travel hundreds

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if not thousands of miles in search of food,

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whereas pygmy seahorses just wait for a meal to come to them.

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They catch plankton as it passes by,

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or pick it from the polyps of the coral,

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while their bigger relatives, like the weedy sea dragon,

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have to go out in search of food,

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putting themselves in the paths of predators.

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This free delivery service means the pygmy seahorse

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never has to leave home...

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..and that's pretty smart.

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Being miniature means that the pygmy seahorse

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can live in a world that is also miniature.

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When it comes to staying out of sight,

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being small offers a huge advantage.

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But do small animals sacrifice strength and power in return?

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Surely the Goliaths of the animal world have the upper hand

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in terms of sheer muscle and might?

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Well, not quite.

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When it comes to brawn,

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it's the little guys that pack the most serious punch.

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I'm in the African bush to meet one of the most impressive.

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You've probably guessed that this little insect is a dung beetle.

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Now, of course, their diet may be unsavoury to us,

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but it clearly works for them.

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Not only have they evolved to feast on the dung of other animals,

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but they are proportionately one of the strongest animals alive.

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Some of these high rollers

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can push balls that are ten times their own weight,

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even up steep hills.

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A Herculean effort with a huge payoff.

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A single ball of dung can be enough to feed them

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for the rest of their lives.

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And they're not the only super-strong insects.

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These are leafcutter ants.

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They carry pieces of leaf

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up to 50 times their own body weight.

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Now, that would be like me trying to carry a van on my back.

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In terms of weight-to-strength ratio,

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this ant is stronger than an elephant.

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In fact, measured this way,

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all of the strongest animals on Earth are tiny

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and it's all to do with physics.

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The Scaling Law means that if you doubled all the dimensions

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of any living thing, it would become eight times heavier.

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So, weight increases more quickly

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than dimensions or size.

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Because strength is determined by how big your muscles are

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compared to your weight,

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animals get heavier more quickly than they get stronger.

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What's more, larger animals

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have to use more energy simply supporting all their bulk.

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So, smaller, lighter animals

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are proportionately stronger than big animals.

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And one of the strongest animals in the world

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is only the size of a peanut.

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The bull-headed dung beetle.

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Whereas an elephant can't even pull twice its own weight...

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..scientists found that the bull-headed dung beetle

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can pull a staggering

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1,141 times their own weight.

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Now, that is the equivalent

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of me pulling six fully-loaded double-decker buses.

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Amazingly, this mighty strength isn't for pushing balls of dung.

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They don't roll their dung away to bury it.

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Instead a pair dig a tunnel directly underneath a big fresh pat

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where the females lay their eggs.

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So, why, then, are they so strong?

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Well, digging might be one reason.

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But there's another more important one.

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A rogue male is searching for a mate down an already-occupied tunnel.

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The horned male needs to keep his mate to himself.

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Intruders have to be pushed out with brute force.

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In their world, strength is king.

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These animals have all found fantastic ways

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of using their small size to solve the big problems

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that all animals face.

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But being small does make some things more difficult.

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I'm going to investigate some of the challenges

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that the smallest animals face because of their size

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and reveal the many ways they've overcome them to succeed.

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One of the biggest problems about being small is temperature.

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Small animals get hot and cold much faster than big animals.

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And this time-lapse footage demonstrates this perfectly.

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There's a good reason why the ice cube on the left is melting faster.

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Because it's smaller.

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It may seem obvious that a small ice cube

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would melt quicker than a large one,

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but have you ever stopped to consider why that happens?

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Well, it all comes down to the amount of surface area an object has

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in comparison to its volume - the physical space that it takes up.

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Because smaller objects have a greater surface area

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in comparison to their volume than larger objects,

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they lose heat quicker.

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That same principle applies to animals too.

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If you're tiny, dealing with temperature extremes

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is a big problem.

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But this hasn't stopped small animals living in extreme places

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because they've found some creative solutions.

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This shovel-snouted lizard

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lives in the blistering heat of the Namibian desert.

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To stop his feet burning on the sand, he's learnt to dance.

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His neighbour, the silver ant,

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has evolved to grow a fine covering of shiny hair

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to reflect the scorching heat.

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But even so, they can only survive

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for up to ten minutes in the midday sun.

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But there's one tiny Namibian mammal

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that's mastered desert survival

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with an impressively large adaptation.

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The fennec is an extraordinary fox.

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Weighing less than a bag of sugar,

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they are the smallest member of the fox family.

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But they've got the biggest ear-to-body ratio of any carnivore.

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These cunning foxes use their oversized ears to radiate body heat.

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Because they're so large and thin,

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they quickly lose heat to the surrounding air

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which cools down their blood

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and stops them from overheating in the searing Sahara sun.

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8,000 miles away in Argentina,

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there's one colourful little animal that's taken desert dwelling

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to a whole new level.

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That is, when you can find one.

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I have been working in the desert in Argentina for 15 years

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and I have never seen a pink fairy.

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They would tell me that Mendoza was a hot spot,

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so I wandered around in the desert,

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looking for pink fairies and just couldn't find them.

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No, not an actual fairy,

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a pink fairy armadillo.

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With its pink back and fluffy white body,

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it's one of the oddest and strangely endearing animals on the planet.

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They are the world's smallest armadillo,

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250 times lighter than their largest relatives.

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They're so elusive, they're only captured on camera

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by locals who have stumbled across them by accident.

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It is very difficult to see a pink fairy armadillo

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because they live underground.

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Most sightings that we have recorded

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are from pink fairy armadillos that were crossing a road,

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so we suspect that they are digging

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and they find a hard underground that they cannot dig through.

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Living underground is a clever way to keep cool.

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Unlike many of their larger relatives,

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they don't even emerge to feed.

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We don't even know if they are rare or if they are very abundant.

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We simply don't know because we can't find them.

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But why do these compact critters look so different to their cousins?

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When you look at these two armadillos,

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the most striking difference, other than their size,

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is their shell.

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This bigger one has what many of us would consider to be

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the classic armoured armadillo shell,

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which pretty much covers its entire body.

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Whereas the shell of the pink fairy armadillo

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only covers the top of its back

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and, in fact, it's only connected along the spine.

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So, it's not really armour for defence,

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but instead, it's another perfectly pint-sized solution

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to control their temperature.

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It's thought that when they want to cool down,

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they pump blood into this shell,

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allowing the heat to be given off to the surrounding environment.

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It's a bit like a hot water bottle -

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as the surroundings get warmer, it gets cooler.

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But when they want to do the opposite and stay warm,

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they drain blood out of the shell

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and back into their furry, insulated bodies.

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It's a fabulous way of keeping their body temperature in check

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and the reason why they're pink.

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Their blood vessels are so close to the surface, they show through.

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Underground, their unusual body also performs another fantastic function.

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Pink fairy armadillos have a rump plate,

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or it's sometimes called a butt plate.

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It's very strong and this is used to compact the soil.

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It starts digging forward and then it backs up

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and it compacts the sand behind it.

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These miniature Argentinian architects

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have carved out a very special niche.

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By trading in their protective shell, they've given up a lot.

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But for this subterranean explorer,

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it works because they rarely ever make an appearance above ground

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and that's why you hardly ever see a pink fairy in the desert.

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Temperature control isn't the only problem that tiny creatures face.

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It's a big world out there and if you've got very short legs,

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it takes much longer to get around.

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This is a money spider.

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It's only about five millimetres long.

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They're found all over the UK,

0:23:370:23:40

but these tiny arachnids are also intrepid explorers,

0:23:400:23:44

capable of covering hundreds of miles...

0:23:440:23:46

..because they've turned their size to their advantage

0:23:480:23:52

and made a home in almost every continent.

0:23:520:23:55

So, how has such a tiny creature

0:23:570:23:59

colonised the far corners of the world?

0:23:590:24:02

It has to do with something that all spiders produce

0:24:020:24:06

and that...is silk.

0:24:060:24:08

It's the spiders' secret weapon.

0:24:100:24:12

They use it to build webs...

0:24:140:24:16

..lay traps...

0:24:190:24:20

..and some even use it to ensnare...

0:24:250:24:28

..or lasso their prey.

0:24:300:24:32

But the smaller spiders use their silk in a very special way.

0:24:390:24:44

When they want to travel,

0:24:480:24:49

they send out a stream of silk which they use to catch the wind...

0:24:490:24:53

..and lift themselves up into the air, like a parachute.

0:24:550:24:59

It's called "ballooning" and it enables small spiders

0:25:010:25:06

to migrate hundreds of miles,

0:25:060:25:08

carried by the wind.

0:25:080:25:11

But colonising continents means crossing oceans

0:25:140:25:18

and they can't control where they land,

0:25:180:25:21

so what happens if an unfortunate spider lands on water?

0:25:210:25:25

Surely, that's the end of its adventures?

0:25:250:25:28

Far from it, because these tiny spiders have a solution

0:25:300:25:34

that has made them record-breaking long-distance travellers.

0:25:340:25:38

Dr Sara Goodacre and a team of scientists

0:25:390:25:42

have been studying these tiny explorers...

0:25:420:25:44

-So, we've got one spider, there.

-Here it goes.

0:25:440:25:47

..and she's going to show me their special skill.

0:25:470:25:50

So, what you can see is that it's floating,

0:25:520:25:54

it's definitely not sinking.

0:25:540:25:56

It's floating across the surface of the water.

0:25:560:25:59

Because they're so light,

0:25:590:26:00

their weight is supported by the surface tension of the water.

0:26:000:26:04

Their legs make tiny dents in it,

0:26:040:26:06

but, miraculously, don't break through.

0:26:060:26:09

-If you look... Look, it's starting to run.

-Isn't that amazing?

0:26:090:26:13

So, for something that's really not supposed to survive on water at all,

0:26:130:26:17

-it's doing rather well.

-Yeah.

0:26:170:26:19

But introduce a breeze...

0:26:200:26:21

OK.

0:26:210:26:23

..and they do something even more astonishing.

0:26:230:26:25

-Let's have a look. Can you see those front two legs?

-Yes!

0:26:280:26:31

This tiny spider is using its raised legs to catch the wind,

0:26:370:26:42

just like a sail.

0:26:420:26:43

There you go. You can see how, all of a sudden, they go so much faster.

0:26:450:26:49

So, it's all about timing and sensing what the wind is doing?

0:26:500:26:54

Once they make the decision to go,

0:26:540:26:56

they're really at the mercy of the winds.

0:26:560:26:59

And what's even more incredible

0:26:590:27:01

is that different spiders have different sailing styles.

0:27:010:27:04

-That one's doing more with its back legs.

-Yeah...

0:27:090:27:12

These are the same species and they're doing different things.

0:27:160:27:19

Sometimes they'll use four legs, sometimes two,

0:27:210:27:24

sometimes the front legs, sometimes the back legs.

0:27:240:27:27

They've got a range of options.

0:27:270:27:28

I guess that kind of gives them their own little personalities.

0:27:310:27:34

Absolutely. And to me, really, it makes perfect sense.

0:27:340:27:36

One strategy doesn't always win.

0:27:360:27:38

By sailing and ballooning in this way,

0:27:430:27:45

these tiny spiders can travel over 40 miles in a single day.

0:27:450:27:50

By utilising the power of the wind,

0:27:520:27:54

they can cross not only whole continents, but the oceans too,

0:27:540:27:58

using virtually no energy.

0:27:580:28:00

And that is what has enabled these tiny spiders

0:28:000:28:03

to colonise almost every part of the globe.

0:28:030:28:07

But not all small animals are international travellers.

0:28:090:28:12

And sometimes, just getting from A to B can be a struggle.

0:28:120:28:18

In the forests of New England in North America

0:28:200:28:23

lives a little squirrel that can fit in the palm of your hand.

0:28:230:28:27

It needs to move from tree to tree in search of food,

0:28:290:28:33

but the trees are widely spaced

0:28:330:28:36

and the forest floor is a dangerous place.

0:28:360:28:40

So, what's a squirrel to do?

0:28:400:28:42

Fly, of course!

0:28:460:28:48

They have a furry parachute-like membrane

0:28:550:28:58

between their wrists and ankles

0:28:580:29:00

that they use to glide effortlessly between trees.

0:29:000:29:03

They're only a quarter of the size of a common grey squirrel,

0:29:070:29:12

but this in-built wingsuit means they can travel much further,

0:29:120:29:16

covering up to 70 metres in a single flight.

0:29:160:29:19

This saves energy and allows them to avoid predators on the ground.

0:29:210:29:26

When trees are close together,

0:29:320:29:34

like in the jungles of Liberia, West Africa,

0:29:340:29:36

travel problems are different.

0:29:360:29:39

Animals like hippos would never be able to get through the trees...

0:29:400:29:45

unless they shrunk.

0:29:450:29:47

And that's exactly what pygmy hippos have done.

0:29:480:29:51

They've evolved a shape and size

0:29:530:29:55

to help them move through the dense jungle.

0:29:550:29:59

It's made for an adorable small animal

0:29:590:30:02

with even more adorable babies

0:30:020:30:05

that have proved to be internet celebrities.

0:30:050:30:09

This pygmy hippo really does look like...

0:30:090:30:12

Hello! ..a scaled-down version of a common hippo.

0:30:120:30:15

But as well as a reduction in size -

0:30:170:30:19

it's about ten times smaller -

0:30:190:30:21

there are a number of other differences

0:30:210:30:23

that make it really well adapted to life in the jungle.

0:30:230:30:26

As well as having much bulkier bodies,

0:30:300:30:32

common hippos' spines are almost parallel to the ground,

0:30:320:30:36

whereas pygmy hippos' backs slope downwards,

0:30:360:30:39

making it easier for them to move through the dense forests.

0:30:390:30:42

While pygmy hippos' eyes are on the sides of their head

0:30:440:30:47

for navigating the jungle floor,

0:30:470:30:49

common hippo eyes are on the tops of their heads,

0:30:490:30:52

for keeping a look out in the water where they spend most of their time,

0:30:520:30:57

which is also why common hippos have webbed feet and pygmies don't.

0:30:570:31:01

Pygmy hippos like this one

0:31:050:31:07

probably weigh about three times as much as I do

0:31:070:31:10

and that just comes down to a diet of leaves, grasses and fruit.

0:31:100:31:14

So, even though they aren't small in terms of sheer weight,

0:31:150:31:18

in comparison to the common hippo, they are miniature.

0:31:180:31:22

Their size and shape means they can effortlessly move

0:31:230:31:27

through the dense forest almost unseen.

0:31:270:31:29

So, by being well adapted to their jungle environment,

0:31:310:31:35

these 300kg animals have almost become invisible.

0:31:350:31:39

Small animals have conquered the problems

0:31:430:31:45

of getting around brilliantly.

0:31:450:31:46

But what about raising the next generation?

0:31:480:31:51

No matter how small you are,

0:31:510:31:54

your offspring will inevitably be even smaller.

0:31:540:31:57

So, if you're pushing the limits of what's possible as an adult,

0:31:580:32:01

having babies that are big enough to survive is going to be a problem.

0:32:010:32:05

But as we'll see, it's another example of how small creatures

0:32:060:32:09

have risen to the challenge.

0:32:090:32:11

This cool little thing

0:32:110:32:14

might look like an earthworm,

0:32:140:32:17

but when you look closely,

0:32:170:32:20

you'll see that it's actually a very tiny snake,

0:32:200:32:23

complete with super small scales and a miniaturised fork tongue.

0:32:230:32:28

These worm-like snakes are found all over the Americas, Asia and Africa.

0:32:290:32:35

This one is a brahminy blind snake and it weighs less than a gram.

0:32:350:32:41

Which is mind-boggling when you consider

0:32:410:32:43

that the largest snakes can weigh more than a fully-grown human.

0:32:430:32:47

And this isn't even the smallest species.

0:32:490:32:51

Thinner than a piece of spaghetti, these thread snakes are even tinier.

0:32:540:33:00

They're 700 times smaller than a large python

0:33:000:33:03

and weigh a staggering 100,000 times less.

0:33:030:33:07

Found only on the Caribbean island of Martinique,

0:33:100:33:13

they've tapped into a food source

0:33:130:33:15

that bigger animals aren't competing for...

0:33:150:33:18

..the eggs and larvae of ants and termites.

0:33:210:33:24

So, their size is an advantage when finding food,

0:33:270:33:31

but being so tiny is an enormous challenge when reproducing.

0:33:310:33:35

Most snakes lay large clutches of eggs -

0:33:370:33:40

in some cases, up to 100 -

0:33:400:33:43

all in the hope that at least some of their hatchlings survive.

0:33:430:33:46

Because they're so short and thin,

0:33:510:33:54

Martinique thread snakes lay just one egg at a time.

0:33:540:33:57

And even though it's only one centimetre long,

0:33:590:34:01

it's still huge compared to the snake's tiny body.

0:34:010:34:04

And that's because when it hatches,

0:34:060:34:08

the single baby snake is already

0:34:080:34:10

half the size of the adults.

0:34:100:34:12

That's in stark contrast to bigger snakes whose hatchlings

0:34:140:34:17

are only around a tenth of their size.

0:34:170:34:19

So, strangely, for their size,

0:34:230:34:26

these tiny snakes have enormous babies.

0:34:260:34:29

And these babies can eat the same food as their parents

0:34:300:34:34

as soon as they're born.

0:34:340:34:36

But this is by no means the only tactic employed by small animals.

0:34:390:34:43

This little critter is a tenrec -

0:34:460:34:49

a hedgehog-like mammal found in Madagascar.

0:34:490:34:52

They feed on insects on the forest floor

0:34:540:34:56

and like all small animals that live on the ground,

0:34:560:34:59

they're vulnerable to predators, even with their protective spines.

0:34:590:35:02

So, to survive as a species,

0:35:040:35:06

tenrecs have taken the absolute opposite approach to babymaking.

0:35:060:35:09

They have more offspring than any other mammal,

0:35:110:35:14

with as many as 32 in a litter.

0:35:140:35:17

And, remarkably, the young can breed themselves

0:35:180:35:21

when they're just 35 days old.

0:35:210:35:23

This brilliant solution means that,

0:35:250:35:27

in contrast to big animals like elephants,

0:35:270:35:30

that are pregnant for nearly two years,

0:35:300:35:32

when conditions are good, tenrecs can have lots of babies.

0:35:320:35:36

But when it comes to bringing up baby,

0:35:420:35:44

there's one species so minuscule it pushes the physical limits

0:35:440:35:48

of being able to reproduce at all.

0:35:480:35:50

Inside this phial is a specimen of the smallest fish in the world.

0:35:550:36:00

In fact, it's so small that it can live

0:36:030:36:04

in nothing more than a mere puddle.

0:36:040:36:07

But miniaturisation on this scale

0:36:070:36:09

comes at an almost unbelievable price.

0:36:090:36:13

Found only in the swamps of Sumatra, Paedocypris progenetica are so rare

0:36:160:36:22

they don't even have a common name.

0:36:220:36:25

They live in a drought-prone world,

0:36:250:36:28

where water comes and goes,

0:36:280:36:30

and for a fish, THAT is a serious challenge.

0:36:300:36:34

The adults are less than eight millimetres long,

0:36:370:36:41

smaller than a 5p piece

0:36:410:36:44

and they have adapted to be this small so a shoal can survive

0:36:440:36:47

in the smallest puddle of water.

0:36:470:36:49

But how is something this tiny still able to bear young?

0:36:510:36:55

The world's smallest fish have evolved

0:36:580:37:00

an astonishingly dramatic physical solution.

0:37:000:37:04

To understand, we have to look at a more average fish.

0:37:040:37:08

The zebrafish is a common aquarium fish

0:37:090:37:12

that scientists often use as a comparison.

0:37:120:37:15

They have a very typical skeleton,

0:37:150:37:18

fully developed bones,

0:37:180:37:20

complete with long ribs,

0:37:200:37:21

and a thick casing around the brain.

0:37:210:37:23

The tiny Paedocypris skeleton is very different.

0:37:250:37:28

The ribs are hardly developed

0:37:280:37:30

and they don't have a proper skull,

0:37:300:37:32

so their brains are actually exposed.

0:37:320:37:34

But here's the weird thing.

0:37:360:37:38

They look remarkably like a zebrafish

0:37:380:37:41

that hasn't fully developed.

0:37:410:37:43

A juvenile.

0:37:430:37:44

And that's no coincidence.

0:37:460:37:48

Because Paedocypris are the Peter Pans of the fish world.

0:37:480:37:52

The fish that never really grows up.

0:37:520:37:55

It's only their reproductive organs that really mature,

0:37:590:38:02

so they can create the next generation

0:38:020:38:04

while keeping as compact as possible to survive through droughts.

0:38:040:38:08

An extreme solution that's extremely clever.

0:38:100:38:14

By finding extraordinary ways

0:38:220:38:24

to overcome the physical barriers of their size,

0:38:240:38:27

all these animals reap the benefits that being little brings.

0:38:270:38:31

But, finally,

0:38:330:38:35

I want to introduce you to some animals

0:38:350:38:37

that refuse to be pigeonholed as small

0:38:370:38:40

and manage to reap the rewards of much larger animals

0:38:400:38:44

in a host of different ways.

0:38:440:38:46

First up, a feisty animal that's found a way of becoming big.

0:38:480:38:54

This is a fire ant and I'm handling it with care

0:38:540:38:58

because they pack a pretty nasty sting.

0:38:580:39:01

Now, as much as they might not be that friendly to me,

0:39:020:39:05

they are, in fact, social insects

0:39:050:39:08

and that means that if one were to sting me,

0:39:080:39:10

that would send a signal to the rest of the colony and, within minutes,

0:39:100:39:13

I could have an entire army on the attack.

0:39:130:39:17

This cooperation is key to overcoming their small size

0:39:220:39:25

and it's crucial where they live.

0:39:250:39:28

They're native to the rainforests of Central and South America

0:39:300:39:34

and with rainforests comes rain.

0:39:340:39:37

Lots of it.

0:39:380:39:39

THUNDER CRASHES

0:39:390:39:42

In fact, one of the biggest problems they face in their underground homes

0:39:420:39:47

is the risk of flooding.

0:39:470:39:49

So, let's see how they deal with getting wet.

0:39:500:39:53

If I gently place this ant in this tank of water...

0:39:550:39:58

We can see that it's not doing particularly well.

0:40:000:40:03

Their exoskeletons do repel water, but other than that,

0:40:030:40:08

they're not particularly well equipped for swimming.

0:40:080:40:11

Just going to fish her out of that water.

0:40:110:40:14

There we go.

0:40:140:40:16

So, I guess the question is, how on earth do these ants cope

0:40:160:40:19

with living in one of the most flood-prone places on the planet?

0:40:190:40:23

That's where working together comes in.

0:40:250:40:27

Inside this beaker are thousands of fire ants.

0:40:280:40:33

And if I just swirl them around...

0:40:330:40:35

Wow.

0:40:350:40:37

They kind of form this ball.

0:40:370:40:39

Wow.

0:40:410:40:42

So, if I keep on moving them around in my hand like this,

0:40:440:40:49

they stay in this cluster and so far, so good.

0:40:490:40:54

Now, watch what happens when I put them in this tank of water.

0:40:540:40:57

Here we go.

0:40:570:40:59

Amazing. So, this ball of ants is staying together...

0:41:000:41:05

..like a raft.

0:41:060:41:08

That is brilliant.

0:41:120:41:13

This is the first time I've seen anything like this.

0:41:150:41:17

Unlike the individual ant,

0:41:170:41:19

they don't have any trouble at all in the water.

0:41:190:41:22

Instead, they form a floating waterproof island.

0:41:220:41:26

And scientists have found that when they raft in this way,

0:41:280:41:32

they can take a force of 400 times their body weight.

0:41:320:41:36

Now, you'd think that the ones at the bottom would be sacrificed.

0:41:380:41:41

But what's happening is that their bodies repel water

0:41:410:41:43

and so that allows for a layer of air to be trapped in the raft

0:41:430:41:47

which means they can still breathe. That is amazing.

0:41:470:41:50

By linking their bodies together,

0:41:550:41:57

they're enhancing their ability to repel water.

0:41:570:41:59

The way they knit together has been likened to the weaving

0:42:020:42:05

of a waterproof fabric.

0:42:050:42:07

These ants are waterproof, flexible,

0:42:100:42:13

and almost completely indestructible.

0:42:130:42:15

In the wild, they can assemble these rafts quickly

0:42:180:42:22

and that's what allows them to endure the epic storms

0:42:220:42:25

in their rainforest home.

0:42:250:42:26

They can survive like this for months,

0:42:290:42:31

spreading out over the water's surface in search of solid ground.

0:42:310:42:35

This is teamwork at its finest.

0:42:380:42:40

When ants behave in this way,

0:42:400:42:41

they display all the hallmarks of a superorganism.

0:42:410:42:44

And they're not the only small animals

0:42:490:42:51

that work together to become bigger.

0:42:510:42:53

Starling murmurations are much more than just hypnotic spectacles.

0:42:570:43:02

They're all about safety in numbers.

0:43:040:43:06

It's much harder for a predator like a peregrine falcon

0:43:100:43:13

to target one small bird

0:43:130:43:15

in the middle of a swirling flock of thousands.

0:43:150:43:17

And when small fish move as one, they're harder to catch,

0:43:220:43:25

so they become much bigger than the sum of their parts.

0:43:250:43:29

But not all small creatures need back up.

0:43:320:43:35

There's one legendary little animal

0:43:370:43:40

that seems to think it's bigger than it is

0:43:400:43:42

and it takes on huge predators all on its own.

0:43:420:43:46

Meet the honey badger.

0:43:480:43:50

It lives on the African plains,

0:43:520:43:54

home to some of the biggest animals that roam our planet.

0:43:540:43:57

Honey badgers live in Southern Africa and Asia

0:44:000:44:03

and they share their home with some of the largest,

0:44:030:44:06

most dangerous predators in the world.

0:44:060:44:08

Lions are the biggest predators in Africa.

0:44:090:44:13

A male can weigh nearly 200kg.

0:44:130:44:16

Whereas a honey badger

0:44:160:44:18

is 20 times smaller,

0:44:180:44:19

weighing in at only 10kg.

0:44:190:44:22

So, when they're out hunting,

0:44:240:44:25

how do they avoid becoming a meal themselves?

0:44:250:44:28

By being a small animal with a seriously big attitude.

0:44:300:44:34

Running or hiding just isn't a honey badger's style.

0:44:370:44:41

For them, the best defence is a good offence.

0:44:410:44:45

The bigger and more intimidating the predator,

0:44:480:44:51

the more feisty the honey badger's response.

0:44:510:44:53

A suicidal strategy, you might think,

0:44:550:44:58

if it weren't for the fact that this fearless fighter

0:44:580:45:01

has a few tricks up its sleeve.

0:45:010:45:04

Aww! What an amazing little guy.

0:45:060:45:10

This is Stompy. He's a hand-reared honey badger

0:45:110:45:15

and he's going to let me show you why honey badgers

0:45:150:45:19

are so resilient,

0:45:190:45:21

very agile

0:45:210:45:23

and also, very muscular,

0:45:230:45:26

which makes them very hard to subdue and pin down.

0:45:260:45:29

Good boy, Stompy.

0:45:290:45:31

This skin is about six millimetres thick in some places

0:45:310:45:36

and it's so tough that even the quills of porcupines

0:45:360:45:39

struggle to get through.

0:45:390:45:41

Not only that, look how loose all that skin is around his body.

0:45:410:45:44

It means that when they're grabbed from behind,

0:45:480:45:50

they're able to twist inside their own skin.

0:45:500:45:53

All this combined means not only can this little honey badger survive

0:45:560:46:00

an attack from a ferocious lion,

0:46:000:46:03

it can actually bite back.

0:46:030:46:05

Their jaws are incredibly strong,

0:46:050:46:09

so not only are they very hard to kill,

0:46:090:46:11

they're also a dangerous opponent.

0:46:110:46:13

Although they're much smaller than many of their adversaries,

0:46:180:46:22

they're built to fight like much larger animals,

0:46:220:46:25

and in my eyes, they're the smallest big predator

0:46:250:46:29

on the African plains.

0:46:290:46:31

HYENAS WHIMPER

0:46:310:46:33

By punching well above their weight,

0:46:330:46:36

honey badgers have found a fantastic way of living alongside

0:46:360:46:40

some of the world's largest predators.

0:46:400:46:43

Their bulletproof build makes up for their small size

0:46:430:46:47

and their big attitude has made them an internet hit.

0:46:470:46:52

Maybe you're one of the 80 million people

0:46:520:46:54

that have watched them online.

0:46:540:46:56

In the depths of the ocean,

0:47:020:47:04

another group of animals reap the benefits

0:47:040:47:07

of being both big and small at the same time.

0:47:070:47:11

Deep-sea anglerfish.

0:47:130:47:15

Ambush predators that entice prey

0:47:170:47:20

with a fantastic bioluminescent lure.

0:47:200:47:23

With those scary-looking teeth and gaping mouths,

0:47:250:47:29

small may not be the first word that springs to mind.

0:47:290:47:33

But in fact, this fearsome-looking fish is hiding a small secret.

0:47:340:47:39

This absolute beast of an animal

0:47:430:47:46

is a female anglerfish

0:47:460:47:49

and it looks quite bizarre.

0:47:490:47:52

What's even more bizarre than that, though,

0:47:520:47:54

is the fact that this is her male counterpart.

0:47:540:47:58

Now, the reason why they look so different

0:48:000:48:02

comes down to something called sexual dimorphism.

0:48:020:48:05

That's where males and females look different.

0:48:050:48:08

In this case, it's an extreme version of exactly that.

0:48:080:48:12

For anglerfish, it's more extreme than in any other animal.

0:48:130:48:18

In some species,

0:48:180:48:20

the males can weigh a staggering half a million times less

0:48:200:48:24

than their female partners.

0:48:240:48:27

So, why on earth are they so small?

0:48:270:48:30

Incredibly, it's to help them survive in the depths of the ocean

0:48:320:48:36

where food is almost impossible to find.

0:48:360:48:39

It is a joint venture and the two sexes

0:48:420:48:45

have very different strategies.

0:48:450:48:47

The females have huge jaws and elastic stomachs,

0:48:490:48:53

so can feast on almost anything they come across.

0:48:530:48:57

They're definitely not fussy eaters.

0:48:570:48:59

The males have also adapted perfectly to deepwater survival,

0:49:000:49:05

but in a completely different way.

0:49:050:49:07

They've evolved to go without food.

0:49:070:49:11

Once they reach adulthood, they stop feeding.

0:49:120:49:15

They use every ounce of energy in their body to find a female.

0:49:160:49:20

The white shape at the front of the male's head are his nostrils

0:49:250:49:29

which are the biggest in proportion

0:49:290:49:31

to their head of any animal on Earth.

0:49:310:49:34

And using these, he sniffs out females in the vast ocean.

0:49:340:49:38

An almost impossible task at which most males probably fail.

0:49:390:49:44

The male's self-sacrifice is a pretty dramatic one,

0:49:450:49:49

but it does make sense.

0:49:490:49:51

Between them, an anglerfish pair

0:49:510:49:53

only need about half the amount of food

0:49:530:49:55

as they would do if they were both large.

0:49:550:49:58

But the question is, how on earth do they mate?

0:49:580:50:01

If he's lucky enough to find a female,

0:50:040:50:06

he bites onto her and releases a chemical

0:50:060:50:10

that fuses his mouth to her body, joining them for life.

0:50:100:50:16

His eyes and fins then waste away

0:50:200:50:25

and he's nourished only by her blood.

0:50:250:50:27

But he still breathes with his own gills and, crucially,

0:50:280:50:32

still produces sperm.

0:50:320:50:33

So, this female has a male attached to her right there.

0:50:370:50:43

You can just make him out.

0:50:430:50:44

And the males pretty much act as a reproductive organ

0:50:440:50:48

that the females carry around.

0:50:480:50:50

Now, when the females want to lay eggs,

0:50:500:50:52

they send a hormonal signal through their blood

0:50:520:50:54

to literally turn him on,

0:50:540:50:56

so that he can fertilise the eggs as they come out.

0:50:560:50:59

Over their lifetime,

0:51:010:51:02

females can collect several males

0:51:020:51:05

who produce sperm season after season.

0:51:050:51:08

By reducing in size,

0:51:080:51:10

the male has given the species

0:51:100:51:12

a better chance of survival

0:51:120:51:14

in one of the most inhospitable places on the planet.

0:51:140:51:17

Another way for small animals to reap some of the benefits

0:51:190:51:22

of being big is, well, to pretend to be big.

0:51:220:51:26

When the white-faced scops-owl feels threatened,

0:51:310:51:34

they make themselves as big and intimidating as they possibly can,

0:51:340:51:39

almost doubling in size.

0:51:390:51:42

Frilled lizards intimidate would-be attackers by opening their mouths

0:51:450:51:50

and expanding the skin around their necks.

0:51:500:51:53

For birds of paradise, it's all about getting a mate.

0:51:580:52:02

They make themselves as big, grand and colourful as they can,

0:52:020:52:06

in the hope of attracting a female.

0:52:060:52:09

There's one final small superstar with an ingenious size solution

0:52:130:52:18

that I want you to meet.

0:52:180:52:21

And it just happens to be the smallest carnivore in the world.

0:52:210:52:24

Hello! Where are you going?

0:52:250:52:28

This little guy...

0:52:280:52:29

HE LAUGHS

0:52:290:52:31

..is Fidget and he's a weasel.

0:52:310:52:33

He's running all over the place!

0:52:330:52:35

They aren't usually this friendly.

0:52:370:52:39

Weasels are actually one of the most ferocious predators out there.

0:52:390:52:43

But Fidget has been hand-reared by wildlife artist Robert Fuller,

0:52:460:52:50

who rescued him when he was abandoned by his mother.

0:52:500:52:53

Robert is obsessed with weasels,

0:52:540:52:57

and he doesn't just paint them, he films them too.

0:52:570:53:01

There's 30 surveillance cameras in the gardens

0:53:020:53:05

covering all the different areas. Nest chambers, pathways.

0:53:050:53:08

So, I'm able to follow the track of the weasels through the garden.

0:53:080:53:12

So, you've got the whole place rigged up?

0:53:120:53:13

-It's a bit like weasel Big Brother!

-It is, yeah, exactly.

0:53:130:53:16

All these cameras here, while I'm painting, in my peripheral vision,

0:53:160:53:19

I can see what's happening with the weasels.

0:53:190:53:22

Although, to me, Fidget seems small,

0:53:300:53:32

in comparison to rodents like mice and voles,

0:53:320:53:35

weasels are actually quite big...

0:53:350:53:37

..or at least that's how they first appear.

0:53:400:53:43

But they've got a surprising trick

0:53:450:53:47

that gives them the best of both worlds.

0:53:470:53:49

And this demonstration should help me to explain.

0:53:510:53:55

My silhouette is a pretty good way

0:53:570:54:00

of getting an idea of my overall size.

0:54:000:54:02

How much space I take up.

0:54:020:54:05

But all you need is a change in perspective

0:54:050:54:08

to see things a bit differently.

0:54:080:54:11

From above, you can see that I appear to be much smaller,

0:54:110:54:15

and could fit into some tight places.

0:54:150:54:17

Just like weasels.

0:54:190:54:21

By being long and thin, they're small in just one direction

0:54:210:54:25

and can squeeze into really tiny spaces.

0:54:250:54:28

So, we've got a 50-mill clear pipe here and we can...

0:54:280:54:33

He's obviously designed to go down vole holes, mouse holes.

0:54:330:54:36

So, that's pretty easy for him.

0:54:360:54:38

Straight through there, yeah. We expected that.

0:54:380:54:41

-We go down onto a 40-mill pipe.

-Wow, you can see...

0:54:410:54:44

I love how he's able to even spin around.

0:54:440:54:47

Yeah, this is important if they get stuck in a mouse hole,

0:54:470:54:50

they've got to obviously find their way out, or a vole hole.

0:54:500:54:53

So, they can spin, twist.

0:54:530:54:55

-He's so nimble!

-Yeah!

0:54:550:54:58

But the challenge for him right now

0:54:580:55:01

is to see if he can make it through...

0:55:010:55:03

-He's halfway through!

-So, is 34...millimetres.

0:55:040:55:08

The smallest tube.

0:55:080:55:09

These tubes are smooth inside, so he can't get any traction.

0:55:120:55:16

But take a look at how Fidget handles some of the other obstacles.

0:55:180:55:22

He can squeeze through tiny tunnels and navigate tight spaces.

0:55:220:55:26

And in the wild, it's even more apparent.

0:55:340:55:37

Watch as this winter-coat weasel

0:55:390:55:41

seems to shrink itself down to the same width as its prey.

0:55:410:55:46

They're thin enough to chase down mice and voles in tiny tunnels,

0:55:480:55:52

but strong enough to overpower them and take down much larger prey.

0:55:520:55:57

Weasels like Fidget are small without being small.

0:56:030:56:07

Which, in my opinion, is a pretty ingenious size solution.

0:56:070:56:10

Although being small does bring some big challenges,

0:56:170:56:22

these animals have found impressive ways of overcoming these problems.

0:56:220:56:26

Reaping the benefits that being smaller brings to them...

0:56:280:56:32

..and turning size to their advantage.

0:56:350:56:38

Because they can grow quicker,

0:56:500:56:52

breed earlier and survive with less food and space,

0:56:520:56:57

they're often better than big animals at coping

0:56:570:57:00

with dramatic changes to their environment

0:57:000:57:03

that could threaten their existence.

0:57:030:57:05

So, although this chameleon looks delicate,

0:57:130:57:16

in many ways, it's less fragile

0:57:160:57:19

than some of the biggest animals on the planet.

0:57:190:57:21

From a primate that's no bigger than a mouse to a chameleon that can fit on your fingertip, the natural world is full of fantastically small animals. Biologist Patrick Aryee explores the fascinating secrets behind these miniature marvels and shows that they're not the underdogs you might think they are.

Firstly, he reveals the huge benefits that being small can bring. There's the little lemur whose diminutive frame helps it to exploit a unique gap in the ecosystem, the tiny hummingbird that uses its size to outmanoeuvre the competition, and the world's smallest seahorse, which never has to leave home. He also explores why small animals are proportionally the strongest in the world and introduces a peanut-sized beetle that can pull over a thousand times its own weight.

Next he explores the challenges that animals face when they shrink in size and the ingenious ways they overcome them. We find out how the smallest armadillo in the world manages to control its temperature in the searing desert sun and how the world's smallest fish can survive in nothing more than a puddle.

Patrick meets a secretive hippo that lives in the dense jungle, as well as some of the world's smallest snakes that give birth to enormous babies. He also meets a scientist that studies how really tiny spiders have a surprising trick that enables them to travel 40 miles per day, using almost no energy.

Then there are the animals that refuse to be pigeonholed as small and manage to punch way above their weight. He puts some astonishing invertebrates to the test to see how they work together to become much bigger than the sum of their parts and meets a pint-sized predator that takes on some of the largest and most dangerous creatures on the planet, getting hands-on to discover how its build helps it to be brave.

Finally he uncovers the incredible lengths that deep sea anglerfish go to in order to be big and small at the same time, and he has an endearing encounter with a tiny carnivore that manages to be small in just one direction.