Episode 1 David Attenborough's Natural Curiosities

The natural world is full of extraordinary animals

with amazing life histories.

Yet certain stories are more intriguing than most.

The mysteries of a butterfly's life cycle

or the strange biology of the Emperor Penguin.

Some of these creatures were surrounded

by myth and misunderstandings for a very long time,

and some have only recently revealed their secrets.

These are the animals that stand out from the crowd,

the curiosities I find most fascinating of all.

In this programme, I investigate creatures

that have taken the ordinary and made it extraordinary.

The chameleon that has an extra long tongue to catch prey...

..and the giraffe with a neck so long it can reach the top of trees.

How and why have these animals stretched nature to the limit?

And also in this programme,

we explore the stories of two animals

that sent shock waves through the scientific world and beyond.

One is a toad that became the centre of a scientific storm

and caused accusations of fakery in the early part of the 20th century.

The other is an Australian animal

that baffled the greatest thinkers of Victorian Europe

and caused many to question whether it was even real.

The chameleon is a truly bizarre creature,

both in its behaviour and its appearance

unlike anything else on earth.

So, not surprisingly, it's given rise to all kinds of legends and myths,

This is The History Of The Four-footed Beasts by Edward Topsell

written in the 17th century.

And he calls the chameleon,

"A fraudulent, ravening and gluttonous beast,

"impure and unclean by the law of God."

Some believed it was constructed by the devil

from parts of other animals,

the tail of a monkey, the skin of a crocodile,

the tongue of a toad, the horns of a rhinoceros,

and the eyes of who knows what.

It was a creature sent to the world to spy for a demon master.

When I first came face to face with the chameleon more than 50 years ago,

I was struck not only by its beauty,

but intrigued by its strange body, particularly by its tongue.

The outlandish appearance of the chameleon

made it much sought-after by curiosity hunters,

but scientists and naturalists too were greatly puzzled

by its extraordinary behaviour and anatomy.

It looked and behaved like no other reptile.

Even today, we're still discovering new things about its unique eyes,

its astonishing tongue,

and its ability to change its appearance.

Chameleons are notoriously hard to find,

partly because they move so slowly,

but also because they match their surroundings

in terms of colour so very well.

This one in front of me is a dwarf chameleon

from Natal in South Africa.

If that's threatened by a snake,

it doesn't bother to change its colour very much,

because a snake's colour vision is not very good,

but if it's threatened by a bird,

it does camouflage itself very well indeed.

Some species of chameleon,

and there are 85 different species in the family,

can even fine tune their camouflage.

If they detect a snake approaching from below,

they become lighter in colour and so less noticeable against the sky.

On the other hand, if the threat comes from a bird,

they become darker to match the background beneath them.

A chameleon's colour is affected not only by its surroundings,

but by the temperature and the light and its emotional state.

Behind this screen there's a rival male.

Let's see what happens if I remove the screen

and let them see one another.

This highly-coloured male is dominant

and he immediately adds bright, aggressive colours to his display.

The other male remains dark

and too frightened to change colour and fight back.

It's clear who's the boss.

Chameleons are emotional creatures,

darker colouration signals anger.

This female on the right is not in the mood

to accept the approaches of this brightly coloured and hopeful male.

Exactly how chameleons achieve such dramatic colour changes

greatly puzzled early naturalists.

An Englishman named Barrow,

who travelled in Africa in the 19th century,

thought the changing colour was caused by something to do with air.

He wrote, "Previous to the chameleon assuming a change in colour,

"it makes a long inspiration,

"the body swelling out to twice its usual size,

"and as this inflation subsides

"the change of colour gradually takes place."

Well, that's an accurate observation of what happens

when a chameleon gets angry and then it's anger subsides,

but actually the change of colour has nothing to do with air.

A French biologist, Mel Edwards, soon after that got it about right.

He wrote, "There exist two layers of membranous pigment

"placed one above the other,

"but disposed in such a way to appear simultaneously under the cuticle

"and sometimes in such a manner that one may hide the other."

Which is indeed so.

Today, we know that the chameleon's skin has three layers

of expendable pigmented cells called chromatophores.

They contain red, yellow, blue and white pigments

with a deeper layer of darker melanin,

which controls the reflection of light.

The chameleons use colour change not only to camouflage themselves,

but also to communicate with one another.

Anyone who looks closely at a chameleon

is bound to be fascinated by its eyes.

They protrude on either side of its head

as though they were mounted on turrets.

And, in fact, their eyelids are fused together

except for one tiny spot right in the middle.

But the most extraordinary thing about them...

is that they move independently.

So that means the chameleon at one and the same time

can be viewing above it and below it.

So any insect that lands nearby

is going to be spotted almost immediately.

It seems that its brain receives separate messages from each eye

and views them and receives them alternately very fast

but independent of one another, they're not integrated.

But the advantage of that is that it does give this

all-round, three-dimensional view

which is unrivalled.

This extraordinary vision is an essential element

in the way the chameleon uses its most astonishing feature,

it's hugely elongated tongue.

How this tongue worked and its construction

greatly intrigued early naturalists - and understandably.

This remarkable preserved specimen shows us in detail

the impressive elongated tongue of a chameleon.

The physical structure of the chameleon's tongue

was easy enough to explain,

although it proved to be a somewhat complicated organ,

a hollow tube with a tapered cartilaginous rod at its base.

The pad at the end was thought to be rough and sticky,

so that it could snag its prey.

But the mystery of how a contraption like this

could be lengthened and projected out of the mouth

took a little longer to fully explain.

Perhaps the way a frigatebird inflates the balloon under its beak,

or how a calling frog blows up its throat sac could give clues,

both do it with air.

Or maybe the tentacles that carry a snail's eye,

it projects them by using its blood as an hydraulic fluid.

But none of them fitted the bill.

It's a much more complex process.

The tongue is a muscular tube

that when relaxed sits on a rod of cartilage.

When the chameleon is ready to strike,

muscles at the back of the tongue push it into launch position.

When the prey is lined up and the distance calculated,

superfast muscles contract

and propel the tongue forward at lightning speed.

As the tongue shoots off the end of the cartilage,

an extra wave of energy drives it forward to its target.

Then, like a stretched elastic band,

its elasticity pulls it back into the chameleon's mouth.

Recently, high-speed images revealed a new detail.

The tip of the tongue, once thought to be sticky,

is covered in microscopic protrusions

that generate suction and secures its prey.

Chameleons really are the most extraordinary creatures

and they hold surprises for us even today.

Only this year, a scientist working in Madagascar

discovered a tiny little chameleon only 29mm long.

It's the smallest known vertebrate in the world.

It's astounding to realise that all the organs of a vertebrate's body

could be fitted into such a tiny little creature,

including that extraordinary tongue.

Next, is the story of another amazing elongated structure,

not a tongue but a neck.

The giraffe is an animal that can't fail to impress.

Up to 6m or 19ft in height,

it's hugely imposing, intriguing in appearance,

and mysterious in its biology.

Our attraction to this unusual creatures goes back centuries.

And one feature in particular has piqued our curiosity -

its elongated neck.

Such a structure seemed an impossibility of nature,

but now we better understand the complex biology

behind the giraffe's bizarre body.

Our growing knowledge of this creature

can be traced back to three very special giraffes

and the story of a royal fascination for the exotic.

In the 19th century, a giraffe named Zarafa, Arabic for "charming one,"

made a big impact on Europe socially and scientifically.

She was one of three captured in 1826 at the order of the Viceroy of Egypt,

who wanted to use them as gifts

to curry favour with France, Austria and England.

Zarafa, the strongest of the three, was given to the French,

seen here in a painting by Jacques Raymond Brascassat.

She travelled from Egypt to Marseilles by ship.

On reaching France, her keepers felt it was too risky to continue by boat,

so the decision was made to walk Zarafa from Marseille in the south

all the way to Paris,

an overland journey of more than 550 miles.

To some, this looked like a journey doomed to failure,

but careful planning and the unique biology of the giraffe

were in its favour.

Very wisely, a forward-thinking and eminent French scientist

called Geoffroy Saint-Hilaire was put in charge of the giraffe.

But there was something very significant about Zarafa

that would be key to the success of her long journey,

it was her age.

She was a youngster, just eight months old.

Baby giraffes are very robust

and can stand up and run within an hour of being born.

They have particularly long legs in relation to their bodies,

only half a metre shorter than those of an adult.

Such long legs help them keep up with their mothers,

so young Zarafa was well-equipped for walking.

Crucial too was the fuel for Zarafa's journey.

Young giraffe suckle for up to a year and Zarafa was bottle-fed.

Throughout the journey, she drank up to 25 litres of milk a day,

supplied by three milking cows.

She marched on at a steady pace with her trusty entourage.

After nearly 200 miles, Zarafa reached Lyon

and Saint-Hilaire broke the walk.

He hoped to put Zarafa onto a boat

to go down-river for the rest of the journey.

As they waited, 30,000 people flocked to see Zarafa.

To the public, she was a strange and exotic creature,

and they were intrigued why such a long neck should exist,

and curious about how an animal could support its weight.

In those early days, giraffe were seen as freaks, strange horned camels

whose humps had been flattened by the stretching of their necks.

But this was exactly what attracted Saint-Hilaire to Zarafa.

He was fascinated by genetic exaggerations

and how they came to be.

Clearly, the giraffe's long neck

enables them to feed on leaves beyond the reach of other browsers.

But how could they physically hold up such a long neck vertically?

DAVID LAUGHS

Studies of giraffe anatomy

have revealed just how the neck is supported.

A long thick ligament like a cable runs the whole length of the neck.

This counterbalances the weight of the head and the neck,

and in its relaxed position, it's tight.

So keeping the neck straight and the head up

involves very little muscular effort.

Bending the neck to reach down is more difficult,

because the tough ligament has to be stretched.

But was the ability to feed from tall trees

the only reason for having a long neck?

As the habits of giraffe in the wild became better known,

people discovered that rival males

fought one another by jousting with their necks.

Was that the reason that they had developed long necks?

But then someone pointed out that the females had long necks too,

so that suggestion was discarded.

In truth, there isn't a neat single answer,

but access to high food, better vigilance

and temperature regulation may all have shaped the giraffe's long neck.

As she walked on, Zarafa continued to attract inquisitive onlookers,

few had set eyes on such a creature, she appeared a natural impossibility.

How could a giraffe pump the blood up such a long neck to its brain?

And why didn't the blood rush back down into its feet?

The giraffe's neck may be very tall,

but, in fact, it contains exactly the same number of bones as our own,

that is to say seven.

But its blood pressure is twice as high as ours.

In fact, it's higher than any other known animal.

The pump that produces this pressure, the heart,

surprisingly is not particularly big but it is hugely powerful.

This is the left ventricle that has been cut through

and you can see how thick the muscle is, getting on for about 8cm.

This great pump produces blood,

squirts it up the artery to the head,

and then when it comes down through the jugular vein

there are pocket-shaped valves

which prevent the blood from flowing backwards into the head

if the animal lowers its head in order to have a drink.

Giraffes find it very awkward to drink from the ground.

And, in fact, they rarely do so,

they get most of their water from leaves and shoots.

The only way to get their mouth down to the water

is to splay their forelegs or bend them at the wrist joint.

The giraffe, in fact, has a relatively short neck compared to its legs.

Antelope and zebra can reach down to the ground

without bending their legs.

Only the giraffe and its rainforest relative the okapi

have necks that are so short relative to their legs

that they must splay or bend them.

So perhaps the most remarkable feature of the giraffe

is the length of its legs.

They certainly were key to Zarafa's success.

At Lyon, there was a plan to rest her legs from walking

and to finish the journey to Paris by boat,

but all didn't go according to plan.

The boat didn't appear in Lyon,

so she walked on and finally got to Paris.

It's took her a total of 41 days

to complete the journey of 550 miles to Paris.

Saint-Hilaire, her trusty companion, was exhausted,

but the giraffe was very fit.

He wrote, "She gained weight and much more strength from the exercise.

"Her muscles were more defined, her coat smoother and glossier

"upon her arrival than they were in Marseille."

Zarafa was presented to King Charles X

and temporarily installed in a greenhouse

in the grounds of the Jardin des Plantes.

She was a true animal ambassador

and 60,000 people saw her in the first three weeks in Paris.

In the early 19th century, giraffes were a novelty

and their biology and lives in the wild was still a mystery.

Zarafa's success was due to a unique interplay

of the giraffe's unusual characteristics and good timing.

Her youth, long legs and a diet with milk

powered her journey right across France.

A body that was first considered bizarre

was revealed to be perfectly evolved.

Our story began with three giraffe that were given to Europe.

Zarafa was the most robust of them and she lived a further 18 years.

The Austrian lasted just a year.

And the one sent to King George IV of England died after two.

Saint-Hilaire learnt much from Zarafa

and he became a key figure

in the blossoming zoological research in France.

The giraffe brought to England

triggered a surge of interest in animal research

that shifted the centre of the zoological gravity

from France to England.

So we can thank Zarafa for her early role

in unravelling the biological mysteries

of the giraffe's extraordinary body and stretched neck.

When the first Europeans arrived in Australia,

they were shocked by the animals they found there.

Nothing in Europe could compare with the bizarre upright grazers

hopping across the grassland landscape

carrying their young in pouches.

Kangaroos were obvious oddities,

but another even stranger creature

also caught the attention of early settlers.

It lived along river banks and swam in the water.

Those first Europeans who saw it called it a "water mole,"

but that name didn't last long.

Inside this box is one of the first specimens of platypus

ever to be seen outside Australia.

It was sent to England in 1798 by Captain John Hunter,

the Governor of New South Wales.

This one small animal would take the scientific world by storm

and transform the careers and reputations

of some of the leading thinkers of the time.

The platypus seemed to be a concoction of different animals,

part bird with its bill and part mammal with its furry body.

When Charles Darwin first encountered one in the wild, it baffled even him.

"Surely," he wrote, "two distinct creators must have been at work."

The task of describing the first platypus specimen

fell to naturalist George Shaw,

who worked in the Department of Natural History in the British Museum.

And he viewed this remarkable specimen

with a fair degree of caution.

This is a first edition of a journal called A Naturalist's Miscellany,

which was published a few years after his examination,

and it contains not only an article by him

but a nice picture of the animal concerned.

And at the end he says, "On a subject so extraordinary as the present,

"a degree of scepticism is not only pardonable but laudable.

"And I ought perhaps to acknowledge

"that I almost doubt the testimony of my own eyes

"with respect to the structure of this animal's beak."

It's said that Shaw was so determined to make sure

that he was not a victim of some elaborate hoax

that he actually cut behind the bill

to make sure it hand't been sewn on by some mischievous forger.

In the late 18th century, the world was opening up,

travellers were returning from overseas with all kinds of wonders.

Among them were specimens of creatures that people had come to think of as being myths,

such as mermen and mermaids.

These were, of course, hoaxes

put together with parts from different animals,

so it's understandable that Shaw had doubts

about the authenticity of his new furry specimen.

Despite his misgivings, he decided to give it a scientific name,

platypus, which means "flat footed."

He didn't know however that a beetle had already been given this name

and some years later, another taxonomist very properly gave it a new one,

Ornithorhynchus, which means "bird snout."

But platypus is still the name that most people use.

But what type of creature was it?

George Shaw believed it to be a mammal because of its furry body.

All mammals feed on milk during the first part of their lives,

milk that is produced by their mother's mammary glands.

But could an animal with a large flat bill really suckle?

Some scientists thought that was impossible,

and anyway they couldn't believe the platypus and the monkey

could belong to the same group of animals.

But that view was to change.

Some 30 years after George Shaw described the platypus,

a German naturalist, Johann Meckel,

produced this wonderful collection of anatomical studies.

Meckel's meticulous and detailed work

would help identify the true nature of this animal.

Here...

..we can see his drawing of a male platypus showing clearly the claw.

Meckel also reported the existence of simple glands

beneath the thick fur of the female platypus,

glands that he suggested secreted milk.

There could be little doubt that these glands produced something,

but even then several scientists doubted Meckel's claims

and suggested rather desperately

that the glands secreted not milk but a lubricant.

Today, we know that Meckel was right.

And I was once able to use an optical probe

to peer into a platypus' burrow

and see a female platypus nurturing her single baby.

Yes! And there it is, it's milk.

Milk is the perfect food,

it provides the growing youngster with everything it wants.

And only mammals produce milk.

In most mammals, of course, it comes from a nipple,

but in this very primitive mammal it simply oozes through the skin.

But 19th-century biologists had no such tricks to help them,

they had to unravel the strange biology of Australian mammals

from just a few shrivelled remains of long-dead specimens.

40 years after their discovery of the platypus,

a brilliant young anatomist, who was to become a giant of 19th-century science, joined the debate.

This is a statue of Richard Owen.

Owen was a formidable man,

the founding Director of the Natural History Museum in Britain,

he was once described as having so much brain as to require two hats.

The platypus would become a central character in Owen's career.

His work on this small creature

would help him secure election to the prestigious Royal Society,

an exclusive group of scientists and thinkers.

Owen had an advantage over his European colleagues.

Australia was a British colony

and Owen used his contacts to supply him with specimens.

Eventually, two baby platypuses arrived

and it was obvious to him that they would have no difficulty in suckling.

They had not yet developed the bill that would have made it awkward.

So he accepted that platypus babies like other mammal babies

were indeed raised on milk.

But the biggest mystery of the platypus was still unsolved.

Did this animal lay eggs just like reptiles or birds,

or did it give birth to live young?

Owen was at the heart of that debate.

These jars contain the bodies of several platypus

that were shot and sent back here to the museum

for Richard Owen to examine.

His determination to prove whether or not they laid eggs

was going to cause the death of quite a number of platypus.

The Australian aborigines were absolutely clear,

they did lay eggs, but that was not good enough for Owen,

he knew better then any Australian aboriginal.

He did concede that it might be

that the eggs were retained inside the body and hatched there

so that the young were born live, but that's as far as he would go.

Eggs were also sent back.

Some of them were fake and some of them belonged to snakes.

It was going to be some decades

before the puzzle of the platypus was finally solved.

The platypus now became embroiled

in the greatest scientific debate of the Victorian era.

Did species evolve or were they created?

Darwin's Theory of Evolution

suggested that species could change over time,

so an intermediate form that laid eggs but had fur like a mammal

was to be expected.

But that was too much of a stretch even for Owen's great brain.

In 1884, more than 80 years after this first platypus specimen

had been examined by George Shaw,

William Hay Caldwell arrived in Australia funded by a Royal Society scholarship.

One of his main aims was to solve the platypus egg question once and for all.

After several months in Queensland,

and with the help of the local aborigines,

he finally got the answer.

He shot a female platypus

soon after she had laid an egg in her nest burrow

with a second egg about to emerge from her vent.

And they looked like this.

It was at last visible evidence that this animal did indeed lay eggs.

He sent a telegram to a scientific gathering in Montreal,

it was brief and to the point,

"Monotremes oviparous, ovum meroblastic."

These four words to the scientifically initiated

meant that the platypus laid eggs

and that the eggs consisted of an undivided large yolk

just like a bird's egg.

The mystery was at last solved.

Richard Owen, who had refused to believe a mammal could lay an egg,

was by now 80 years old and he was no longer held in the same esteem

as in the early part of his career.

The platypus had helped establish his reputation,

but now the riddle of this creature's reproduction had proved him wrong.

It's extraordinary to think that this small animal

fooled and confounded many of the great scientific minds of 19th-century Europe.

Not a hoax, but a true curiosity and one like no other.

The egg-laying platypus was hardly believable to Victorian researchers,

but evolution has thrown up many unusual mating strategies

and in the early part of the 20th century,

the anatomy of a particular amphibian started an argument

that, like the platypus, led to accusations of forgery.

This is the curious tale of the midwife toad.

Midwife toads are not native to Britain,

they were introduce about a century ago

and since then have been slowly spreading over England.

Their natural home is Europe, from Germany to Spain.

And in the 1920s, their mating habits caused a media sensation.

Investigations into the way the body of the male toad

changed according to its environment led some to believe

it might be possible to breed a race of superhumans.

To understand why, we must first know

what makes the midwife toad so different from any other frog or toad.

Amphibians were among the first backboned animals to take to the land.

Since then, they've colonised most habitats

from rainforests to deserts and mountains.

Despite spending much of their lives on land,

most frogs and toads need water to reproduce,

whether it be in a small vase plant or a large lake.

But mating in water is a slippery business.

Male toads, however, have a special adaptation,

black warty swellings on their wrists called nuptial pads,

which enable them to grip their partners securely during sex.

Once the female produces her eggs,

the male releases his sperm and then let's go, his job is done.

But midwife toads are different,

the male does not have nuptial pads on his wrists.

And that's because he doesn't mate in water, he mates on land.

The female produces her eggs and then he takes them around his legs

with an action that's been compared to a man trying to put on his trousers without using his hands.

So it is the male toad that is the actual midwife, not the female.

Midwife toads tend to live in places where open water is scarce.

Once the male has successfully wrapped a string of eggs around his legs,

he usually hides under a rock where it's suitably damp.

He may have as many as 150 eggs

and he hides away for up to two months while they develop.

Then, just before the eggs hatch,

he sets off to find water for his emerging tadpoles.

Now, the tadpoles of most frogs and toads

turn into the adult form within a matter of weeks,

but not so the midwife toad - it takes much, much longer.

In fact, sometimes they may even overwinter in the form of a tadpole,

which is why perhaps midwife toad tadpoles are such whoppers.

Frogs and toads are widely used in biological studies

because they're easy to keep

and the different stages of their life cycles are easy to observe.

So it's no surprise that the unusual behaviour of the midwife toad

should attract the attention of many biologists.

One was an Austrian scientist called Paul Kammerer,

who worked in Vienna in the early part of the 20th century.

And his discoveries quickly brought him great fame.

But the toad would become a curse

that would haunt him until the end of his life.

Kammerer was greatly influenced

by the great French zoologist Jean-Baptiste Lamarck,

who, in 1799, published his theory

that characteristics acquired by an animal during its life

could be inherited by its offspring.

That a giraffe, for example,

reaching upwards to nibble the topmost shoots of trees

would, over time, lengthen its neck muscles

and that this increase would then be inherited by its offspring.

And so on for generation after generation.

Lamarck's theory was largely rejected after Charles Darwin proposed

a different mechanism for evolution

based on changes to an animal's genetic make-up.

Kammerer was keen to prove that Lamarck was right after all.

But giraffes are not the ideal experimental animal,

so he needed one he could keep in a lab and that would reproduce quickly.

And his attention fell on the midwife toad.

Kammerer became fascinated

with the unusual nature of the midwife toad's reproduction.

Why did males like this one

carry eggs around his legs and could this be changed?

He wondered if their biology might be related to their natural environment, which is largely arid.

Kammerer decided to see what would happen

if he kept the toads in a warm, humid tank

with access to pools of cool water.

His work with the toads would last many years

and involve several generations, but eventually he noticed changes.

Some male toads abandoned carrying the eggs

and instead the females laid them directly in water.

Over several generations, Kammerer had managed to change the midwife toad

from being a land-breeding animal to one that bred in water.

But the most extraordinary discovery came as he continued breeding these toads.

He noticed that the wrists of some of the males

developed warty-looking structures

just like the nuptial pads of other frogs and toads

which are normally used by males

to grip females when fertilising her eggs.

His work suggested that somehow,

by altering the environment in which they lived,

a toad's body could be changed

and that change was then passed on to future generations.

Kammerer's work was taking place at the end of the First World War

and political movements on the left and the right

were then keen to exploit scientific discoveries.

Despite his subject being a small toad,

some saw an opportunity to extend his findings beyond the laboratory.

He was hailed as a second Darwin in the New York Times.

Some newspapers got carried away

and suggested that Kammerer's discoveries could apply to humans.

His work could help, in other words, to breed a race of superhumans.

Whether he liked it or not, Kammerer was now in the spotlight.

He set off on a lecture tour across Europe and America.

In Cambridge, the Professor of Zoology hailed his achievements

and put one of Kammerer's toads on display.

But not everyone was convinced.

An American zoologist by the name of GK Noble wrote a damning article

in the prestigious scientific journal Nature.

Noble examined one of Kammerer's toad

and declared that its black nuptial pads were fakes,

produced by injecting a black dye.

Kammerer denied this. Someone, he said, had interfered with his specimens

and was trying to ruin him.

But the damage to his name was done.

Six weeks after the Nature article accusing him of forgery,

Kammerer wrote a letter to another leading scientific journal.

This is an extract of what it said.

"On the basis of this state of affairs,

"I dare not, although I myself have no part in these falsifications of my prior specimens,

"any longer consider myself a proper man to accept your call.

"I see that I'm also not in a position to endure this wrecking of my life's work,

"and I hope I shall gather together enough courage and strength

"to put an end of my wrecked life tomorrow."

Soon after writing that letter,

he walked into the hills around his home and shot himself.

Whether or not Kammerer's suicide

was purely down to the fallout from his midwife-toad experiments, we can't be sure -

there were many other problems in his personal life -

but there can be little doubt that the scandal surrounding his work

would have weighed heavily on his mind.

Since Kammerer's death, a specimen of male midwife toad

WITH nuptial pads has been found in the wild.

Some scientists now believe

that environmental influences can change the way some genes behave

and that these changes can indeed be passed on to the next generation.

Perhaps midwife toads possess the gene to grow these structures,

but it's only switched on in certain situations.

Does this prove Kammerer was right?

No-one has been able to repeat Kammerer's experiments with midwife toads,

so we don't know for sure if he falsified his findings,

or whether he had stumbled upon a quirk of inheritance ahead of its time

and beyond the understanding of scientists of his era.

What is certain is that the nature of how species inherit their characteristics

is more complex than he or others at the time originally thought.

The curious lives of the midwife toad and the duck-billed platypus

perplexed and wrong-footed science for some considerable time.

But in the end, both these creatures

helped us to better understand the way animals evolve.