The Book of Animal Ignorance

Aardvark

Ancient, odd, and out on its own

Aardvarks are the last survivors of a primitive group of mammals that have lived in Africa since the dinosaurs. They were originally classified alongside anteaters and armadillos in the order Edentata ("no teeth"), but they are not remotely related, having evolved on different landmasses.

In fact, aardvarks don't have any close relatives: they are the only mammal species that boasts an entire order to itself. Tubulidentata means "tube-toothed" and aardvark teeth are completely different from those of any other animal. They are twenty flat-topped pegs, made up of hexagonal tubes, right at the back of their mouths. Instead of enamel, they are covered with cementum, the stuff that is normally inside teeth. Like rodents' teeth, they never stop growing.

The aardvark has a primitive, "designed by committee" look to it: the nose of an anteater, the ears of a donkey, the feet of a rabbit, and the tail of a giant rat. But don't be fooled: it has outlasted many other species because it does one thing supremely well. It is a termite-eating machine.

As soon as darkness falls it leaves its burrow and applies its snout to the ground, snuffling in huge zigzags across the savannah in search of mounds to crack open and lick clean. It can cover thirty miles and vacuum up more than ten pints of termites in a single evening. The aardvark nose contains more bones and scent receptors than that of any other mammal. Its ears can pick up the tiniest of underground movements and its powerful claws tear open mounds that would blunt a pickax. Aardvarks are strong: they can grow to the size of a defensive tackle and dig a burrow faster than six men using shovels. Their thick skin protects them from termite bites, and as the long, sticky tongue reels in supper, they can close their nostrils at will, to stop the insects running up inside.

They have also built up a remarkably beneficial relationship with a plant known as the aardvark cucumber, which grows its fruits underground. Aardvarks dig them up and eat them when water is scarce, then bury their seed-laden droppings, ensuring the plants' survival. The San (bushmen) of the Kalahari call the fruit "aardvark dung."

Humans and hyenas are the only predators that will attack a fighting-fit aardvark. Despite its solitary, reclusive nature, a cornered aardvark is a formidable foe, slashing with its claws, kicking its legs, and executing high-speed forward somersaults.

Aardvarks are hunted for meat and leather: aardvark is Afrikaans for "earth pig" and they are said to taste like gamey pork. They are also called ant bears, but their Latin name, Orycteropus afer, means "African digger-foot." The bushmen believe that aardvarks have supernatural powers because they are literally in touch with the underworld.

This elusive nocturnal animal probably only became known in the English-speaking world because it is so close to the start of the dictionary. It very nearly didn't make it. Aardvark, the fourth noun listed in the 1928 Oxford English Dictionary, owes its inclusion to the editor James Murray, who overrode his assistant's opinion that the word was too technical.

Albatross

Flying nonstop for a decade

There are twenty species of albatross from the gull-sized sooty to the vast wandering albatross (Diomedes exulans, or "albatross in exile"), with its record eleven-foot wingspan. They fly farther and for longer than any other family of birds. Satellite tracking reveals that some albatrosses fly around the entire planet in less than two months and can soar for six days without flapping their wings. Rather than soaring high up in the thermals like birds of prey, they keep close to the surface of the sea, using the lift generated by wind from waves. The most energetic part of any albatross flight is takeoff: it is the only time the bird needs to flap its wings vigorously.

As soon as a young wandering albatross gets airborne it won't land again until it is ready to breed, which can be ten years later. Albatrosses feed on fish, squid, and krill, either diving into the sea or picking it off the surface, and sleep on the wing, with each half of the brain taking turns to shut down.

Albatrosses belong to the order Procellariiformes, originally Tubinares, which means "tube-nosed." These tubes run the length of their large, hooked beaks and lead to very well developed scent organs, allowing them to detect their food and nesting sites from many miles away. In some species the tubes have a dual function, allowing them to breathe from one part while sneezing excess sea salt from another.

Young albatrosses spend several years watching their elders to learn the elaborate beak-clacking courtship dances. When they find a partner, they mate for life, developing a unique body language, which they use to greet each other after long separations. They raise only one egg every two years, with the parents taking turns to sit on the nest or go off in search of food. An albatross will regularly fly one thousand miles for a single mouthful for its chick. Solid food is regurgitated, but for longer journeys it can also be broken down into a concentrated protein-rich oil, kept in their stomachs. This can be used in place of water to quench their thirst, or regurgitated as a nutritious fish smoothie for the chick.

Albatrosses can live for sixty years but breed so slowly that they are at risk of extinction within the next century. The main threat is long-line fishing. More than one hundred thousand die each year, caught in the millions of baited hooks that are used to catch tuna.

Samuel Taylor Coleridge's poem The Rime of the Ancient Mariner (1798) practically invented the myth that killing an albatross brought bad luck. In fact, British sailors regularly killed and ate them, making pipes from their bones and purses from their feet. A more widespread belief was that the albatross was the reincarnated spirit of a drowned sailor. Some Scottish fishermen still don't like using Swan Vesta matches because the bird on the box looks like an albatross.

When Portuguese explorers first saw them they called them alcatraz, their name for any large seabird. The word originally came from the Arabic al-gatta¸s, the leather bucket on a waterwheel, which resembled a pelican's bill. So, in Portuguese, the Birdman of Alcatraz literally means the "Birdman of the Large Seabird."

Anglerfish

Worse things happen at sea

Surely a life doesn't get any bleaker than that of the deep-sea anglerfish? Two miles down in the endless darkness, a gloomy motionless lump of brittle bone, atrophied muscle, and paper-thin black skin with only luminous bacteria for company. A life spent doing nothing except waiting, often for months at a time, turning your light on and off in the hope that it will attract some other creature out of the inky gloom long enough for them to stray too close to your cavernous mouth. . . .

The name "anglerfish" is used for about three hundred species--including sea toads, frogfish, batfish, and monkfish--that attract their prey with a long, flexible appendage like a fishing rod, typically growing out of the middle of their heads. At the end of it, in place of a dangling maggot, there is the esca (Latin for "food"), which can be wiggled to mimic live bait. On the deep-sea anglers, the esca lights up, thanks to a chemical process controlled by the bacteria that live on it. In return for light, the anglerfish supplies them with food. Different anglerfish have differently shaped escas. It was once thought this was to attract different prey, but it's now believed that they all have a similar diet. Perhaps having a big, bendy, glowing rod sticking out of your head is a form of sexual display.

The deep-sea anglers are some of the most ugly and outlandish creatures on the planet. They have an elastic stomach that can swallow prey twice as large as themselves (it even has a lightproof lining in case they swallow luminous fish). To prevent their prey escaping they have backward-facing teeth in their mouths and another set of teeth in their throats. The female illuminated netdevil (Linophryne arborifer) looks like a fluorescent root vegetable, with a black bulbous body and two shimmering lures streaming off like psychedelic foliage. Her Latin name means "tree-shaped toad that fishes with a net." The hairy seadevil's (Caulophryne polynema) huge spiny fins have a decayed look, its body is covered in unpleasant pale hairs, and its lure looks like a frayed stick of licorice. It has one of the most sensitive lateral lines of any fish--the tiniest movement triggers the opening and closing of its jaws. Elsman's whipnose (Gigantactis elsmani) swims along upside down, trailing its lure along the seabed. The wolftrap seadevil (Lasiognathus saccostoma, or "hairy-jawed sack-mouth") has a lure with three shining hooks on the end that it casts forward like a fly fisherman. Prince Axel's wonderfish (Thaumatichthys axeli) has its lures hanging down from the roof of its mouth like a pair of fluorescent tonsils.

The male deep-sea anglerfish is much smaller than the female and doesn't have a lure. He's interested in mating, not fishing. He uses his giant eyes to look for a suitable female, and his enormous nostrils to sniff out her pheromones. Having found her, he latches on to 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 sperm. Females have been found with eight testes attached to their sides.

In some species, if the male fails to find a female, then he will eventually turn into one himself and grow massively in size. As the anglerfish themselves are wont to remark: there's only one thing worse than being an anglerfish and that's being a male anglerfish.

Ant

Chemical-dependent

Ants boggle the mind. In the jungles where three-quarters of them live, they teem 800 to the square yard, 2.4 billion to the square mile, and collectively weigh four times more than all the neighboring mammals, birds, reptiles, and amphibians put together. The 12,000 named ant species come in all shapes and sizes: a colony of the smallest could live happily inside the braincase of the largest. As with bees and termites, their success flows from their social organization, but there is nothing remotely cuddly about ants: they are the storm troopers of the insect world, their ruthlessly efficient colonies operating like a single superorganism.

Every process within an ant colony is regulated by chemicals. In some species, this can be refreshingly direct: the queen will climb to a high point when she is ready to mate, then stick her backside in the air and release a love pheromone that inflames the ardor of all males in range. Ant species mate in a variety of ways: in midair, on the ground, or in a mating ball, where the queen is completely surrounded by a swarm of love-addled males.

As well as love charms, pheromones also act as air-raid sirens. If the colony is threatened, many species emit a pheromone from a gland in their mouths. This causes some workers to grab the larvae and run underground while others prance around with their mandibles open, ready to bite and sting. Brunei ants even have guards that explode their own heads when threatened, leaving a sticky mess that slows down the intruders.

Interspecies warfare is common and ant raiders will take hostages back to their own colony, where they make them slaves. Other species use this to their advantage: the queen of Bothriomyrmex decapitans allows herself to be dragged to the nest of rival species, where, like a mini-Trojan horse, she bites off the head of the host queen and begins laying her own eggs. Being ants, the host workers switch loyalty without batting an antenna.

Some ants raise livestock. They collect the honeydew made by aphids and in return protect them from other predators. The ants "milk" the honeydew by gently stroking the aphid's abdomen with their antennae. Meanwhile, more than two hundred species of ant are arable farmers, farming fungi for food. They gather compost for it to grow on, fertilize it with their dung, prune it, and even fumigate it with powerful bacteria to keep it parasite-free.

But for all their awe-inspiring industry and adaptive Þlan, ants don't get it all their own way. The South American bullet ant (Paraponera clavata) is one of several species that finds out too late that fungi can sometimes farm them. Spores from a Cordyceps fungus work their way inside the ant's body and release an override pheromone that scrambles its orderly world. Confused and reeling, the ant 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.

Armadillo

The best-endowed of all mammals

If the male nine-banded armadillo (Dasypus novemcinctus) were human, its penis would be four feet long. When you're making love to something that resembles an upturned fishing dinghy, size matters.

Describing armadillos has always been a challenge: the Aztecs called them azotochtli, "turtle rabbits."

All twenty species live in the Americas. The smallest is the pink fairy armadillo (Chlamyphorus truncatus), which is no longer than a sausage and looks like a furry prawn. The screaming hairy (Chaetophractus vellerosus) armadillo squeals like a pig when disturbed, though this seldom happens: it spends seventeen hours a day asleep and often won't wake even if you pick it up or hit it with a broom.

The giant armadillo (Priodontes maximus) weighs up to 135 pounds (heavier than most Texan cheerleaders), sports lethal 9-inch claws, and has the largest number of teeth of any mammal: a hundred tubular pegs that never stop growing. The three-banded armadillo (Tolypeutes tricinctus) is the only one that can roll into a ball.

Nine-banded armadillos (despite the handicap of having wedding tackle big enough to scratch their own chin with) are strong swimmers. They swam the Rio Grande in 1850 and spread to most of the southern United States where there are now between thirty and fifty million of them.

They have two ways of getting across rivers. Their bony armor means they naturally sink, so they can just stroll along the bottom, holding their breath for up to six minutes. If they need a longer swim, they gulp down air and inflate their stomachs into life jackets.

Males mark their territory with urine and their smell has been likened to that of an elderly blue cheese. To avoid giving birth in the winter, females can hang on to a fertilized egg for up to two years.

Other than humans and mice, nine-banded armadillos are the only animals seriously afflicted by leprosy: most armadillos in Louisiana are lepers.