Animals have this in common with each other: unlike humans they appear to spend every minute of every hour of every day of their lives being themselves. A tree frog (so far as we can ascertain) doesn't wake up in the morning feeling guilty that it was a bad tree frog the night before, nor does it spend any time wishing it were a wallaby or a crane-fly. It just gets on with the business of being a tree frog, a job it does supremely well.
We humans, well… we are never content, always guilty, and rarely that good at being what nature asked us to be - Homo sapiens.
There is much to be learned from the animals. Much to be learned about them, of course, but much, much, more to be learned about ourselves: our limits, our lonely uniqueness as a species and, I would add, our greatness.
The fact that we care with un-reciprocated fervour about woodlice, woodpeckers and wolverines is to our credit. I cannot subscribe to this modern idea that we should feel guilty about our role on Earth, or inferior for having evolved a (self-)conscious mind. This is just Genesis wrapped up in new, even more sanctimonious clothes. The old religion and the new orthodoxy both claim we have guardianship over Earth and a "moral" responsibility for its destiny. Well, fine. But I will not apologise for committing the crime of being born, any more than a marmot or a mosquito should. And between them, those two have been responsible for more death and upheaval than all human wars.
In the end, whatever weird and unfathomable purposes there might be to existence, to whichever theory of the development of life you might subscribe, we all have to face the fact that there is no entirely satisfactory explanation for the oddities and extremities of the zoological world.
Nothing in nature seems to follow a fixed predictable law, not the number of penises on an insect, not the need for a chicken to have a head. I suppose they all have in common the melancholy fact that they have been impersonated, with the use of nothing more than a mop of hair, expressive hands and a pair of big brown eyes, by Mr Alan Davies.
25 animal facts
1. ANGLERFISH
The male deep-sea anglerfish is much smaller than the female. But he has giant eyes to look for a suitable female and enormous nostrils to sniff out her pheromones.
Having found her, he latches onto her with his teeth and then starts to disappear. Scales, bones, blood vessels all merge into those of the female. After a few weeks, all that's left of the male are the testes hanging off the female's side, supplying her with his genes.
2. ANT
More than 200 species of ant farm fungi for food. They gather compost for the fungus to grow on, fertilise it with their dung, prune it and even fumigate it with a powerful bacteria to keep it parasite-free. But they don't get it all their own way. Several species find out too late that fungi can sometimes farm them.
Spores work their way inside the ant's body and release an "override" pheromone that scrambles its orderly world. Confused and reeling, it finds itself climbing to the top of a tall plant stalk and clamping itself there with its jaws. Once in place, the fungus's fruiting body erupts as a spike from the insect's brain and sprinkles a dust of spores on the ant's unsuspecting sisters toiling below.
3. BEAVER
In 1760, the College of Physicians and Faculty of Divinity in Paris classified the beaver as a fish because of its scaly tail. This meant that the French settlers in North America could officially eat beaver during Lent and on other fast days. Beaver tail is supposed to taste like roast beef.
4. BEE
Bees can recognise human faces. Given that many humans struggle with this once they have turned 40, it seems utterly remarkable in a creature whose brain is the size of a pinhead. Yet bees who are rewarded with nectar when shown some photos of faces, and not rewarded when shown others, quickly learn to tell the difference. Not that we should read too much into this. Bees don't "think" in a meaningful way. The "faces" in the experiment were clearly functioning as rather odd-looking flowers, not as people they wanted to get to know socially.
5. BEETLE
If diversity and adaptability are the measuring sticks for success, then beetles are the most successful animals on the planet. There are 350,000 known species, with up to eight million more out there waiting for names: new species are being discovered at an average rate of one an hour. If you lined up all animal and plant species in a row, every fifth species would be a beetle. There are about 750,000,000,000,000,000 individual beetles going about their business right now.
6. CATFISH
Catfish are swimming tongues: they have more taste buds than any other creature. Their entire bodies are covered with them. A six-inch catfish may have more than a quarter of a million taste buds, not just in its mouth and gills, but on its whiskers, fins, back, belly, sides and tail. The channel catfish has the best sense of taste of any vertebrate and is able to detect less than a hundredth of a teaspoonful of a substance in an Olympic swimming pool full of water.
7. CHEETAH
The modern cheetah population can be traced back to a single African group of 500 animals that survived the last ice age. Genetically, this means all living cheetahs are as close as identical twins. They are notoriously difficult to breed in captivity because the female needs to be chased by several males before she can ovulate. Akbar the Great, the 16th-century Mogul emperor, kept more than 1,000 cheetahs but managed only one litter. The next cheetah born in captivity wasn't until 1956.
8. EEL
Nowadays, "everybody knows" that eels are born in the Sargasso Sea, but this has never been proved. No one has ever seen an eel spawn or die there. Careful scientists prefer to call the Sargasso Sea the eel's "presumed" breeding ground. Young eels have been found there, but not live adults or their eggs. Not one eel has been bred in captivity. When you catch an eel, its reproductive system shuts down completely, as if deliberately keeping the secret.
9. GOOSE
Despite having acquired a reputation for stupidity, geese show signs of great sensitivity and intelligence. Many species mate for life and the death of a loved one provokes behaviour that is remarkably similar to our own. They honk mournfully, stop eating, hunch up their feathers and can remain that way for months.
If a partner is shot down, they will return to earth to stand vigil next to its corpse. In 19th-century Ireland, geese were pulled up chimneys by a rope tied to their legs, their frantic wing beats dislodging the soot.
10. GORILLA
Gorillas are the strong, silent members of the ape family. They aren't as vocal or flashy with their skills as chimps or bonobos, but they have better memories and often do things independently rather than simply for a reward.
Koko, a female gorilla born at San Francisco zoo in 1971, has mastered up to 1,000 words in sign language and seems able to communicate complex emotions such as sadness and even make jokes. She describes herself, touchingly, as "fine animal person gorilla".
11. KOALA
Koala means "no water" in the now extinct Dharuk language of south-eastern Australia. Koalas hardly ever have to drink because their diet consists entirely of eucalyptus leaves, which are 50 per cent water. They can even tell the age of the leaves by their smell. To qualify as lunch they have to be between a year and 18 months old, as young leaves have almost no nutritional value and older leaves contain poisonous prussic acid. Eucalyptus is so low in energy that koalas spend 20 hours a day asleep, like sloths.
12. LIZARD
Geckos can walk vertically up glass and scientists have recently discovered how. Their feet are covered in half a million tiny hairs, each of which splits into hundreds more with diameters less than the wavelength of light.
This creates a powerful bond between the electrons in the two surfaces. One square centimetre of adhesive tape based on this principle has already been manufactured. If enough can be made to cover a human hand, you could hang by it from the ceiling.
13. MONKEY
An experiment with rhesus macaques revealed that they would "pay" to look at pictures of the faces and bottoms of high-ranking females, by forfeiting their usual reward of a glass of cherry juice. With low-ranking females, however, the researchers had to bribe them with an even larger glass of juice before they would pay any attention.
14. OCTOPUS
The male blanket octopus takes sexual discretion to a whole new level. He is 40,000 times smaller than the female and his technique involves tearing off his mating arm, placing it somewhere on her body and then swimming off to die.
Given that this is roughly equivalent to a herring nudging a blue whale, it's unlikely she's even aware of him. Meanwhile, his disengaged arm crawls into her gill slit, where it can live for as long as month, until her eggs are mature. She then retrieves it, tears it open like a packet of café sugar and sprinkles the sperm over her eggs.
15. PARROT
The nocturnal, flightless kakapo from New Zealand is one of the world's rarest birds. As well as being easy prey for rats and dogs, its mating ritual does them no favours. The male constructs a mating court on top of a mountain, excavating several shallow "bowls" connected by a series of tracks, which he keeps scrupulously clean. Every evening, he hunkers down in each of his bowls in turn, pumps up a special air sac and emits a sequence of low-frequency "booms" that can be heard three miles away.
It may take him months to attract a female, during which time he can lose half his body weight. Some females shuffle 20 miles. If both are still in the mood, they mate for 10 minutes and then she walks home again and tries not to get eaten.
16. PENGUIN
Adélie penguins build their nests with stones, a rare commodity in Antarctica and one for which they are willing to pay. When their partner's back is turned, they trade intimate favours with other single males in return for bigger, better stones - the only known example of bird prostitution.
"Client" males are sometimes so satisfied with the service that females can come back for more stones without offering sex, merely a little light courtship. The males clearly believe the loss of stones is worth it for the opportunity to father more chicks. Zoologists speculate that the female may be trying to improve the genetic variability of her offspring. Or she could just be having fun.
17. PIGEON
To keep alive in the wild, a pigeon needs to keep its eyes open for predators. Having eyes on the side of its head gives it a field of view of 340 degrees and, in order to fly at speed, its brain can process visual information three times faster than a human's. If a pigeon watched a feature film, 24 frames per second would appear to it like a slide presentation. They would need at least 75 frames per second to create the illusion of movement on screen. (This is why pigeons seem to leave it until the very last second to fly out of the way of an oncoming car: it appears much less fast to them.)
18. RAT
A rat can swim for 72 hours non-stop. It can jump down 50 feet without injury. It can squeeze through a half-inch gap, leap three feet, climb vertical surfaces and walk along ropes. It can survive longer than a camel without water. It will eat anything that's edible and lots of things that aren't (lead sheeting, soft concrete, brick, wood and aluminium).
It reaches sexual maturity at three months. An on-heat female can have sex more than 500 times with a barnload of different males and produce 12 litters of 22 young each year. In short, rats are very, very hard to get rid of.
19. SALAMANDER
Newts are members of the salamander family that breed in water. They are the only vertebrates that can regenerate large parts of themselves, growing new limbs, spinal cords, hearts, jaws, tails and even eyes.
As the damaged part heals, the cells reverse their original function and turn back into an undifferentiated lump called a blastema (from the Greek blastos for "bud"), from which the replacement limb or tissue grows. How the cells know what to grow isn't understood, but salamanders are being studied closely to see whether or not human tissue could be stimulated to regenerate.
20. SCORPION
Scorpions give birth to live young and some species are pregnant for longer than humans. They are one of the very few invertebrates to have independently evolved a womb where embryos are fed by teats linked to the mother (rather than by the yolk of an egg). Labour can take days, with up to 100 offspring scurrying up their mother's claws to nestle on her back underneath her sting, so nothing can get to them. Nothing that is, except the mother who, if she gets hungry, may snack on them herself.
21. SEA CUCUMBER
Sea cucumbers, close relatives of the starfish, are the oceans' binmen - they process more than 90 per cent of all the dead plant and animal material that settles on the sea floor. Their bodies are made from a connective tissue called "catch collagen", which gives them an almost miraculous ability to change from solid to fluid in order to escape predators.
Some species can blow themselves up to the size of a football. Others expel water to make themselves look like pebbles. The ultimate cucumber party trick is to blow their guts out of their bottom and flood the water around with a toxic soup. Known as a "cuke nuke", it can wipe out all the fish in a small aquarium, as well as the cucumber itself.
22. SPIDER
Spiders' silk is five times stronger than steel and 30 times more stretchy than nylon. An average spider will spin more than four miles of silk in a lifetime and this can be collected and woven into garments.
However, the spiders' predatory nature makes them tricky to farm: put 10,000 spiders in a sealed room and you will eventually end up with a single enormously fat spider. (Despite their reputation, female black widows only eat one in ten of their mates, although they can get through twenty five partners in one day.)
23. TARDIGRADE
Tardigrades are plump, microscopic creatures that fall somewhere between worms and insects. Also known as water bears or moss piglets, they are the toughest animals on the planet. If their water supply dries out, they dry out, too. All life processes come to a complete stop and they become totally inert.
In this "dead" state, tardigrades are practically indestructible: they have been frozen to within a degree of absolute zero (-272°C) and heated to temperatures of 151°C. They have been immersed in chemicals and squeezed by pressures six times greater than those at the bottom of the ocean: but, like living granules of instant coffee, with one drop of water they come back to life - even a century later.
24. WALRUS
When walruses find a clam, they hold it firm in their lips, create a vacuum around it and use their tongue like a piston to extract the soft tissue. As a special treat, they hoover up seagulls from underneath or suck the brains of seal pups out through their nostrils. Walruses have a sucking power three times stronger than the average Dyson vacuum cleaner, which explains why their stomachs are full of small pebbles.
25. WASP
The Asian giant hornets of Japan, also known as the Yak Killer, are the super-predators of the wasp family. They are enormous - like flying thumbs, with a quarter-inch sting. Their venom is strong enough to dissolve human tissue and they kill more than 50 people a year. But the Japanese get their own back in style: they serve the larvae raw as hornet sashimi and deep-fry the adults, which are reputed to taste like sweet prawns.
