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Some animals live extremely long lives, | 0:00:02 | 0:00:05 | |
but how does their skin help them on their journey to old age? | 0:00:05 | 0:00:10 | |
Curious questions like this have always fascinated me. | 0:00:11 | 0:00:15 | |
I've had the good luck to meet some very interesting creatures, | 0:00:16 | 0:00:20 | |
but some are particularly unusual. | 0:00:20 | 0:00:23 | |
We've known about some of these animals for centuries. | 0:00:24 | 0:00:27 | |
Others we've discovered more recently. | 0:00:27 | 0:00:30 | |
In this series, I unravel some of their stories | 0:00:31 | 0:00:34 | |
and reveal why they're considered natural curiosities. | 0:00:34 | 0:00:38 | |
The elephant and the mole rat are curious creatures. | 0:00:48 | 0:00:52 | |
They're both extremely wrinkled, starting their young lives | 0:00:53 | 0:00:57 | |
looking ancient and remaining that way into old age. | 0:00:57 | 0:01:00 | |
Yet they outlive most other animals their size. | 0:01:01 | 0:01:05 | |
What are their secrets? | 0:01:05 | 0:01:07 | |
Elephants are truly strange creatures, | 0:01:20 | 0:01:23 | |
both in looks and behaviour. Aristotle described them as | 0:01:23 | 0:01:28 | |
"the beast that passeth all others in wit and mind". | 0:01:28 | 0:01:33 | |
But the more we learn about its curious body and behaviour | 0:01:33 | 0:01:36 | |
the more remarkable it appears to be. The evolution | 0:01:36 | 0:01:39 | |
of such a strange-looking creature is no accident. | 0:01:39 | 0:01:42 | |
Its fascinating body is the key | 0:01:42 | 0:01:45 | |
to allowing elephants to live a long life. | 0:01:45 | 0:01:48 | |
For elephants - even young ones - | 0:01:48 | 0:01:50 | |
it's an advantage to be wrinkly and not at all a sign of old age. | 0:01:50 | 0:01:54 | |
Elephants evolved from mammoths over 55 million years ago. | 0:01:57 | 0:02:02 | |
Today, they're the heaviest land mammals alive | 0:02:02 | 0:02:05 | |
and one of the longest lived, with a life expectancy of about 70 years. | 0:02:05 | 0:02:10 | |
Big creatures usually live a long time | 0:02:12 | 0:02:14 | |
largely because they have slow metabolisms. | 0:02:14 | 0:02:17 | |
However, elephants have particular characteristics | 0:02:17 | 0:02:20 | |
that help them reach old age. | 0:02:20 | 0:02:23 | |
One of the most important, a family structure | 0:02:23 | 0:02:25 | |
in which the oldest matriarchs pass on vital experience. | 0:02:25 | 0:02:29 | |
And their bodies have developed some special features | 0:02:30 | 0:02:33 | |
to deal with the problems of being so big. | 0:02:33 | 0:02:36 | |
Their trunk is one of them. | 0:02:36 | 0:02:38 | |
This surely is the most extraordinary nose | 0:02:40 | 0:02:44 | |
possessed by any living creature. | 0:02:44 | 0:02:47 | |
It can be moved with ease and dexterity to gently caress, | 0:02:48 | 0:02:53 | |
tear down trees, suck up litres of water. | 0:02:53 | 0:02:56 | |
The trunk is, in fact, a union between the nose and the upper lip | 0:02:56 | 0:03:01 | |
and it's highly sensitive, with over 100,000 muscle units in it. | 0:03:01 | 0:03:06 | |
The end of the trunk can move rather like a hand. | 0:03:06 | 0:03:10 | |
This mobile tip allows the elephant to feel | 0:03:10 | 0:03:14 | |
and pick up delicate objects such as a single blade of grass. | 0:03:14 | 0:03:18 | |
The stretched nose is a masterpiece of evolution and key | 0:03:19 | 0:03:24 | |
to how the elephant can survive with such a large and curious body. | 0:03:24 | 0:03:29 | |
If they hadn't developed a trunk, | 0:03:32 | 0:03:34 | |
elephants couldn't have become so big. | 0:03:34 | 0:03:37 | |
It enables them, in spite of their huge stocky body, | 0:03:38 | 0:03:41 | |
to reach down to the ground to collect food and water. | 0:03:41 | 0:03:45 | |
Fuelling a big body is a full-time job | 0:03:46 | 0:03:49 | |
and an elephant has to consume its own weight in food every 20 days. | 0:03:49 | 0:03:54 | |
One might think this great weight | 0:03:55 | 0:03:57 | |
would be a stress on joints and teeth, | 0:03:57 | 0:04:00 | |
and wear elephants out before old age, but not so. | 0:04:00 | 0:04:04 | |
Eating vegetation is, of course, very tough on the teeth | 0:04:05 | 0:04:09 | |
and there are some animals that, when their teeth are worn down, | 0:04:09 | 0:04:12 | |
simply starve and die. | 0:04:12 | 0:04:15 | |
But elephants can live to 70 years old | 0:04:15 | 0:04:19 | |
and their secret lies in their extraordinary molar teeth. | 0:04:19 | 0:04:24 | |
They have two pairs - two at the top, two at the bottom | 0:04:24 | 0:04:27 | |
and here's one of them. | 0:04:27 | 0:04:29 | |
This is the grinding surface which is capable | 0:04:29 | 0:04:33 | |
of shredding twigs and bark and even wood and, of course, it wears. | 0:04:33 | 0:04:39 | |
But as it wears down, so another tooth is developing within the jaw, | 0:04:39 | 0:04:44 | |
which finally emerges and pushes this forward | 0:04:44 | 0:04:47 | |
until it actually breaks off and is shed. | 0:04:47 | 0:04:51 | |
Acquiring new teeth in that way enables elephants | 0:04:53 | 0:04:56 | |
to remain well-fed and healthy into old age. | 0:04:56 | 0:04:59 | |
In elephant society, the older females are invaluable | 0:05:01 | 0:05:04 | |
and pass on the wisdom they've gained during their long lives | 0:05:04 | 0:05:07 | |
to younger members of the family. | 0:05:07 | 0:05:09 | |
Mature females spend long periods of time listening out | 0:05:14 | 0:05:18 | |
for vital sounds of danger and warn the group. | 0:05:18 | 0:05:21 | |
Such sensitivity to sound was the subject | 0:05:23 | 0:05:26 | |
of one of the very first animal behaviour experiments. | 0:05:26 | 0:05:30 | |
Someone in France in the early 18th century noted that | 0:05:33 | 0:05:37 | |
elephants in menageries appeared to react to faint distant sounds | 0:05:37 | 0:05:42 | |
outside their enclosures. | 0:05:42 | 0:05:45 | |
So they tested two elephants - Hans and Parkie - | 0:05:45 | 0:05:49 | |
and engaged a Paris orchestra to play love music to them. | 0:05:49 | 0:05:53 | |
One elephant was very impressed by the French horn player. | 0:05:54 | 0:05:58 | |
It was reported that, "The animal knelt down before him, | 0:05:58 | 0:06:03 | |
"caressed him with his trunk, and expressed to him in all sorts | 0:06:03 | 0:06:06 | |
"of pretty ways the pleasure which it had felt in listening to him." | 0:06:06 | 0:06:11 | |
We now know that the French horn can produce a low-frequency sound | 0:06:14 | 0:06:19 | |
that's very like the rumble that elephants produce | 0:06:19 | 0:06:22 | |
using a similar resonating chamber in their heads. | 0:06:22 | 0:06:25 | |
LOW RUMBLE | 0:06:25 | 0:06:27 | |
They can also hear very deep sounds, beyond our own hearing. | 0:06:29 | 0:06:34 | |
The oldest, experienced females are experts at interpreting them. | 0:06:34 | 0:06:39 | |
Such frequencies create vibrations in the ground that travel | 0:06:40 | 0:06:44 | |
a very long way which the elephants can detect through their feet. | 0:06:44 | 0:06:48 | |
Their feet, in fact, are not as solid as they might look, | 0:06:50 | 0:06:53 | |
but have special internal cushioning | 0:06:53 | 0:06:55 | |
to soften the impact of the animal's weighty footsteps. | 0:06:55 | 0:06:58 | |
For such a large creature, that can be 40 times our weight, | 0:07:00 | 0:07:05 | |
this foot seems unfeasibly small. | 0:07:05 | 0:07:09 | |
Its surface area is little more than twice our own feet | 0:07:09 | 0:07:12 | |
but this foot has a surprising structure. | 0:07:12 | 0:07:16 | |
The elephant walks on five toes | 0:07:16 | 0:07:19 | |
and the back part of its foot consists of a highly spongy heel. | 0:07:19 | 0:07:24 | |
The raised heel can compress and expand to absorb shock | 0:07:24 | 0:07:29 | |
and shield the other heavy bones in the body from pressure. | 0:07:29 | 0:07:32 | |
It's as if the elephant were wearing a high-heeled training shoe. | 0:07:32 | 0:07:37 | |
When an elephant runs, it bounces on this spongy heel | 0:07:37 | 0:07:41 | |
and its leg bones act like pogo sticks to push the animal upwards. | 0:07:41 | 0:07:47 | |
This system protects the bones and inner tissues | 0:07:49 | 0:07:53 | |
and wild elephants rarely get arthritis. | 0:07:53 | 0:07:56 | |
Despite their large size, they live active physical lives | 0:07:59 | 0:08:03 | |
without too much damage to their bodies. | 0:08:03 | 0:08:05 | |
Males, as they mature, usually go off to live by themselves, | 0:08:08 | 0:08:12 | |
but the females stay with the family group | 0:08:12 | 0:08:14 | |
and play a very important part in guiding the younger ones. | 0:08:14 | 0:08:18 | |
Young elephants tend to look old, even at the start of their lives, | 0:08:22 | 0:08:25 | |
because of their wrinkly skin. | 0:08:25 | 0:08:27 | |
But for elephants, wrinkles are not signs of ageing. | 0:08:28 | 0:08:32 | |
On the contrary, | 0:08:32 | 0:08:33 | |
they're extremely important for an elephant's very survival. | 0:08:33 | 0:08:37 | |
The elephant's thick, creased skin has been the subject of much debate | 0:08:38 | 0:08:43 | |
over the years and early anatomists had some novel ideas about it. | 0:08:43 | 0:08:47 | |
Many believed that the elephant could actually move its skin | 0:08:47 | 0:08:51 | |
to crush flies between the wrinkles. | 0:08:51 | 0:08:53 | |
I may say that was never witnessed in action. | 0:08:53 | 0:08:57 | |
But the skin was thought to be enormously thick and insensitive, | 0:08:57 | 0:09:01 | |
but, in fact, it varies across the elephant's body | 0:09:01 | 0:09:04 | |
and can be as thick as two or three centimetres | 0:09:04 | 0:09:06 | |
around the top of its trunk and along the back, | 0:09:06 | 0:09:09 | |
and as thin as paper around the eyes. | 0:09:09 | 0:09:12 | |
Although the skin looks tough and wrinkly, it's remarkably sensitive. | 0:09:12 | 0:09:16 | |
An elephant can feel small flies on its body | 0:09:16 | 0:09:19 | |
even if it can't crush them between its wrinkles. | 0:09:19 | 0:09:22 | |
But these wrinkles really do have an important function. | 0:09:24 | 0:09:29 | |
The patterned crevices hold water, | 0:09:29 | 0:09:31 | |
which travels along them all over the body. | 0:09:31 | 0:09:34 | |
Wrinkly skins can retain five to ten times more water than smooth ones, | 0:09:34 | 0:09:39 | |
so moisture collected during wallowing stops the skin | 0:09:39 | 0:09:43 | |
from dehydrating and overheating for a long time afterwards. | 0:09:43 | 0:09:47 | |
Significantly, African elephants that live in hotter, drier places | 0:09:49 | 0:09:53 | |
have more deeply wrinkled skins than Asian elephants. | 0:09:53 | 0:09:59 | |
So wrinkles, for the elephant, are ways of protecting the skin - | 0:09:59 | 0:10:04 | |
not the unwanted consequence of old age. | 0:10:04 | 0:10:07 | |
The elephant was once considered an oddity of nature. | 0:10:10 | 0:10:14 | |
For centuries, we've been fascinated by their large ears, | 0:10:15 | 0:10:19 | |
their extraordinary trunks, the stocky feet, the wrinkly skins, | 0:10:19 | 0:10:24 | |
but over the years, we've come to understand their significance. | 0:10:24 | 0:10:28 | |
The elephant's unique biology is key to its long-term survival | 0:10:28 | 0:10:32 | |
and its ability to seemingly avoid the rigours of old age. | 0:10:32 | 0:10:37 | |
Elephants understandably live a long time | 0:10:43 | 0:10:47 | |
because of the slow metabolism of their huge bodies. | 0:10:47 | 0:10:50 | |
But small naked mole rats live much longer | 0:10:52 | 0:10:55 | |
than any other mammal of a comparable size. Why? | 0:10:55 | 0:10:59 | |
Could it be that the body of this bizarre little creature | 0:11:01 | 0:11:04 | |
holds the secret of eternal youth? | 0:11:04 | 0:11:07 | |
When a German naturalist, Wilhelm Ruppell, discovered a lone, | 0:11:10 | 0:11:17 | |
hairless, wrinkled naked mole rat in 1842 in Ethiopia, | 0:11:17 | 0:11:22 | |
he was convinced that he had stumbled across | 0:11:22 | 0:11:25 | |
a decrepit old individual | 0:11:25 | 0:11:27 | |
and he gave it the name "heterocephalus glaber", | 0:11:27 | 0:11:31 | |
which, loosely translated, means | 0:11:31 | 0:11:33 | |
a smooth-skinned animal with an oddly-shaped head. | 0:11:33 | 0:11:36 | |
He noted that the form of the body, because of its hairlessness, | 0:11:37 | 0:11:42 | |
gives an unpleasant impression. | 0:11:42 | 0:11:44 | |
It does. | 0:11:45 | 0:11:46 | |
For the next 40 years, | 0:11:49 | 0:11:51 | |
these bizarre-looking creatures were largely ignored by scientists. | 0:11:51 | 0:11:56 | |
Then, in 1885, a British zoologist in London's Natural History Museum | 0:11:56 | 0:12:01 | |
called Oldfield Thomas decided to examine in detail | 0:12:01 | 0:12:05 | |
the museum's specimens that had been sitting in store for decades. | 0:12:05 | 0:12:09 | |
Here we can see some of his drawings. Thomas declared that | 0:12:11 | 0:12:16 | |
the weird animal described by Ruppell was, in fact, normal. | 0:12:16 | 0:12:20 | |
We now know that all mole rats look like this, whatever their age. | 0:12:20 | 0:12:25 | |
However, what those earlier naturalists couldn't have known | 0:12:25 | 0:12:28 | |
was that they had chanced upon a mammal that would fascinate | 0:12:28 | 0:12:32 | |
and intrigue scientists for the next 150 years. | 0:12:32 | 0:12:36 | |
A creature that might even shed light | 0:12:36 | 0:12:39 | |
on the secrets of ageing and longevity. | 0:12:39 | 0:12:42 | |
Its body hardly seemed to alter, no matter how long it lived. | 0:12:44 | 0:12:48 | |
Old mole rats stayed physically young throughout their lives. | 0:12:50 | 0:12:54 | |
And not only that - the strangest discovery of all | 0:12:55 | 0:12:58 | |
was that they sometimes lived for almost 30 years. | 0:12:58 | 0:13:03 | |
The life span of animals varies enormously. | 0:13:06 | 0:13:10 | |
Amongst mammals, a tiny little shrew like this | 0:13:10 | 0:13:13 | |
lives just two or so years, | 0:13:13 | 0:13:15 | |
while a giant whale can reach the age of 100. | 0:13:15 | 0:13:19 | |
Lifestyle is an important factor in defining lifespan. | 0:13:20 | 0:13:25 | |
A shrew has a fast and furious life, | 0:13:25 | 0:13:29 | |
producing many young, of which few survive. | 0:13:29 | 0:13:32 | |
Whales on the other hand breed slowly | 0:13:32 | 0:13:35 | |
and don't have many predators. | 0:13:35 | 0:13:36 | |
Generally, big animals live longer. | 0:13:37 | 0:13:41 | |
So it's very odd indeed that mole rats live up to nine times longer | 0:13:41 | 0:13:47 | |
than any other similar-sized rodent. | 0:13:47 | 0:13:50 | |
Why? | 0:13:50 | 0:13:52 | |
In the 1960s, more than 100 years after their discovery, | 0:13:52 | 0:13:56 | |
scientists started keeping the animals in laboratories | 0:13:56 | 0:14:01 | |
to try and answer that question. | 0:14:01 | 0:14:03 | |
The results were confusing. | 0:14:03 | 0:14:05 | |
The mole rats lived in colonies and only a few females ever reproduced. | 0:14:05 | 0:14:11 | |
Around that time, an evolutionary biologist called Richard Alexander | 0:14:11 | 0:14:15 | |
was studying the way colonial insects, | 0:14:15 | 0:14:18 | |
such as termites, organised their colonies. | 0:14:18 | 0:14:21 | |
They have a single breeding female who produces huge numbers | 0:14:21 | 0:14:25 | |
of non-breeding workers, a system called eusociality. | 0:14:25 | 0:14:29 | |
He speculated that if there were such things as a eusocial mammal, | 0:14:29 | 0:14:34 | |
it too, like termites, would live underground in hard soil. | 0:14:34 | 0:14:38 | |
He was right. | 0:14:39 | 0:14:40 | |
The naked mole rat perfectly fits Alexander's description | 0:14:43 | 0:14:48 | |
of what a eusocial animal should be like. | 0:14:48 | 0:14:51 | |
There it is. | 0:14:52 | 0:14:53 | |
It lives underground in large social groups | 0:14:54 | 0:14:58 | |
and digs for tubers in exceptionally hard soil. | 0:14:58 | 0:15:02 | |
Physically, it's evolved for a life below ground. | 0:15:03 | 0:15:06 | |
It has a long, thin body with short legs that suit life in a tunnel. | 0:15:06 | 0:15:11 | |
Its enlarged, strong teeth are used for digging, | 0:15:11 | 0:15:14 | |
its skull is strong, the head quite large, | 0:15:14 | 0:15:18 | |
lips closed behind its teeth to stop any soil going into its mouth. | 0:15:18 | 0:15:22 | |
Also it's almost entirely bald, except for a few sensory hairs. | 0:15:22 | 0:15:28 | |
Could it be that these extraordinary characteristics have something to do | 0:15:28 | 0:15:34 | |
with their ability to live very, very long lives? | 0:15:34 | 0:15:36 | |
They're certainly key to the mole rats' unusual life underground. | 0:15:39 | 0:15:43 | |
The queen is at the heart of the colony. | 0:15:45 | 0:15:47 | |
She mates with just two or three males | 0:15:47 | 0:15:50 | |
and produces babies in huge litters, sometimes of more than 20. | 0:15:50 | 0:15:54 | |
The workers feed the queen, care for the young and guard the tunnels. | 0:15:56 | 0:16:01 | |
Their role is essential. | 0:16:01 | 0:16:02 | |
The colony would not survive if all its members didn't work together. | 0:16:02 | 0:16:06 | |
The tubers that they eat are hard to find on the dry African plains | 0:16:10 | 0:16:15 | |
and the workers have to dig miles of tunnels in their search for them. | 0:16:15 | 0:16:20 | |
The fact that they don't breed might seem hard, | 0:16:20 | 0:16:23 | |
but their mother, the queen, does | 0:16:23 | 0:16:25 | |
and her DNA is virtually identical to theirs. | 0:16:25 | 0:16:29 | |
And, by working together, the colony can live in places | 0:16:29 | 0:16:33 | |
where an individual mole rat could not. | 0:16:33 | 0:16:35 | |
But this still doesn't explain why these creatures live so long. | 0:16:37 | 0:16:41 | |
More recently, another adaptation to life underground threw up a clue. | 0:16:41 | 0:16:46 | |
Fossil records show that mole rats started living underground | 0:16:47 | 0:16:51 | |
about 24 million years ago. | 0:16:51 | 0:16:53 | |
Not surprisingly, they're now highly adapted | 0:16:53 | 0:16:56 | |
to a life in dark and humid tunnels. | 0:16:56 | 0:16:58 | |
Conditions in a sealed, two-metre-deep tunnel system | 0:16:59 | 0:17:02 | |
don't fluctuate greatly and, maybe because of this, mole rats | 0:17:02 | 0:17:06 | |
have lost the ability to regulate their own body temperature. | 0:17:06 | 0:17:09 | |
So, to prevent getting chilled, they huddle together in groups. | 0:17:09 | 0:17:14 | |
They also, like reptiles, absorb heat by basking in the warmer, | 0:17:14 | 0:17:19 | |
shallow surface tunnels. | 0:17:19 | 0:17:20 | |
Being hairless might be an advantage for an animal | 0:17:22 | 0:17:24 | |
that's essentially cold-blooded | 0:17:24 | 0:17:26 | |
and needs to get some of its heat from its surrounding | 0:17:26 | 0:17:29 | |
and that may explain why naked mole rats are virtually bald. | 0:17:29 | 0:17:33 | |
But why are not other warm-blooded mammals | 0:17:34 | 0:17:37 | |
that live underground also bald? | 0:17:37 | 0:17:40 | |
Badgers, for example, have hairy coats. | 0:17:40 | 0:17:43 | |
Well, badgers come above ground to feed | 0:17:46 | 0:17:50 | |
and then they need their hairy coats to keep warm. | 0:17:50 | 0:17:53 | |
Naked mole rats, on the other hand, never see the light of day. | 0:17:56 | 0:17:59 | |
Nonetheless, one might think that being soft skinned | 0:17:59 | 0:18:02 | |
and bald is a huge disadvantage, | 0:18:02 | 0:18:05 | |
for mole rats live in stuffy insanitary conditions. | 0:18:05 | 0:18:08 | |
Mole rats colonies can contain several hundred individuals | 0:18:10 | 0:18:13 | |
and conditions underground are dark and dank and often quite toxic. | 0:18:13 | 0:18:18 | |
Oxygen levels can be very low and carbon dioxide high. | 0:18:18 | 0:18:22 | |
Yet, mysteriously, mole rats show no discomfort | 0:18:22 | 0:18:25 | |
and suffer very little from disease. | 0:18:25 | 0:18:28 | |
This tolerance to such hostile conditions may also be related | 0:18:28 | 0:18:31 | |
to their strange wrinkled skin and the cells below it. | 0:18:31 | 0:18:35 | |
Apparently, they lack a key neuro-transmitter, | 0:18:36 | 0:18:40 | |
called Substance P, that is normally responsible | 0:18:40 | 0:18:44 | |
for sending pain signals to the central nervous system. | 0:18:44 | 0:18:47 | |
This may explain their ability | 0:18:48 | 0:18:50 | |
to survive the toxic conditions underground | 0:18:50 | 0:18:53 | |
without stress and damage to their bodies. | 0:18:53 | 0:18:56 | |
It could also be one of the secrets of their youthful appearance - | 0:18:56 | 0:19:00 | |
if you can call it that - and even their longevity. | 0:19:00 | 0:19:03 | |
Most animals react strongly to pain and this can damage their bodies. | 0:19:08 | 0:19:14 | |
In mole rats, this effect is eliminated | 0:19:18 | 0:19:21 | |
by cutting out the pain response. | 0:19:21 | 0:19:23 | |
Incredibly, no mole rat has ever been found with cancer. | 0:19:25 | 0:19:30 | |
But even if a normal animal survives disease, it still ages. | 0:19:30 | 0:19:35 | |
This is largely due to other chemicals in the body | 0:19:35 | 0:19:39 | |
called oxidising agents. | 0:19:39 | 0:19:41 | |
They build up with time and break down the body tissues. | 0:19:41 | 0:19:44 | |
This leads to the telltale signs of old age. | 0:19:46 | 0:19:49 | |
Incredibly, mole rats appear to have no physical reaction | 0:19:53 | 0:19:58 | |
to high levels of oxidising agents. | 0:19:58 | 0:20:01 | |
They grow very old, yet they don't physically age. | 0:20:01 | 0:20:05 | |
In wild mole rats, the queen is the most long lived | 0:20:07 | 0:20:11 | |
and one of them here is 24 years old, | 0:20:11 | 0:20:14 | |
yet she still has the body of a two-year-old. | 0:20:14 | 0:20:18 | |
No-one is sure how mole rats avoid the symptoms of old age, | 0:20:18 | 0:20:22 | |
but a unique physiology evolved in response to the underground life | 0:20:22 | 0:20:26 | |
has created an animal that is almost supernatural. | 0:20:26 | 0:20:30 | |
Here's a creature that's seemingly impervious to pain | 0:20:30 | 0:20:34 | |
and with an iron constitution. | 0:20:34 | 0:20:36 | |
It's virtually cold blooded, with a slow metabolism, and has evolved | 0:20:36 | 0:20:41 | |
an unusual mix of strategies to deal with its challenging lifestyle. | 0:20:41 | 0:20:45 | |
In the future, these remarkable animals may help us | 0:20:45 | 0:20:48 | |
solve some of our own problems such as pain control, | 0:20:48 | 0:20:51 | |
degenerative disease, | 0:20:51 | 0:20:53 | |
and how we might avoid old age and wrinkly skins. | 0:20:53 | 0:20:57 | |
Here is a natural curiosity that is well worth pursuing. | 0:20:58 | 0:21:03 | |
Both elephants and mole rats remain much the same as they grow old. | 0:21:05 | 0:21:10 | |
And, surprisingly, the small naked mole rat lives, relatively speaking, | 0:21:10 | 0:21:15 | |
even longer than the elephant. | 0:21:15 | 0:21:18 |