by Ted Dewan
Research has proved what every cat owner knows: apart from human beings, cats have a wider range of personalities than any other creature on the planet. And yes, they are intelligent. Very. When they can be bothered. There are numerous well-documented stories of cats abandoned by their owners tracing them to locations hundreds of miles from home. Can cats map-read? Maybe. They can certainly tell the time, as recent experiments have shown. The ancient Egyptians worshipped cats as gods: killing a cat, whether deliberately or not, was a capital offence. When a cat died, its owner was expected to shave off his eyebrows. Whose idea was that? A cat’s, of course. Cats don’t have eyebrows.
ONE BLIND CAT
Catfish
Swimming tongue
There are over 2,200 species of catfish and they are found on every continent except Antarctica. They live in the frozen rivers of Siberia and the steamy swamps of Borneo. Species have been found in the Himalayas and the Andes at altitudes of over 14,000 feet, while others bask in the warm coral reefs of the South Pacific. They range in size from some of the smallest known fishes to the largest. Scoloplax dicra is fully grown at half an inch while the European wels (Silurus glanis) grows to 16 feet and can weigh 650 lb.
Catfish account for about 8 per cent of all fish and are among the most remarkable creatures on earth. There is a talking catfish, a walking catfish, an electric catfish, an upside-down catfish and a catfish that looks like a banjo, but what really makes them stand out is their senses – the most finely tuned in nature. They have more taste buds than any other creature. Their entire bodies are covered with them. A 6-inch catfish may have over 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, able to detect less than a hundredth of a teaspoonful of a substance in an Olympic swimming pool full of water.
Food historian and diplomat Alan Davidson once cancelled an official reception so he could travel north to taste and record a rare catch of the world’s largest freshwater fish, the pa beuk or Giant Mekong catfish. He considered its flavour ‘unmatched … comparable to veal’.
Catfish also have extraordinary senses of smell, touch and hearing. They can smell some compounds at a dilution of 1 part in 10 billion. They have no visible external ears, but because they are the same density as water, their whole body acts as a giant ear. In addition, ultra-low-frequency sound is picked up by the lateral line, small pores along the fish’s side containing tiny hair-like projections that are supersensitive to vibrations. These are used to find prey and avoid predators. The Chinese have exploited this talent for centuries, using catfish to warn of earthquakes: they are said to be able to detect them days in advance.
Catfish do not have scales – their smooth skin gives them a heightened sense of touch – and some also have excellent eyesight, especially the channel catfish (Ictalurus punctatus, Latin for ‘spotted fish-cat’) whose eyes are used for medical research into vision. Other parts are used to study herpes, their gonads are removed for research into reproduction and, if that were not enough, this unfortunate creature (variously known as the willow cat, forked-tail cat, spotted cat or lady cat) is also delicious. It ranks third after bass and crappie as the most popular fish to catch in Texas. As well as all the familiar senses, catfish – like sharks – have an extra one called electroreception that detects the electrical fields of worms and larvae buried in mud. Most catfish are harmless to humans (though some can give you a nasty jab with their toxic spines) but beware the candiru, a tiny catfish that lives in the Amazon. If you swim in its murky waters and urinate, the fish will find its way into your urethra. Once inside, it erects its spines, causing inflammation, haemorrhage and death.
THE MOUTHBROOD DIET
Cheetah
The savannah strangler
Cheetahs used to range across the whole of Africa and most of southern Asia. Over the past century, their population has shrunk dramatically as a result of hunting for fur and to protect livestock. Of the 12,000 surviving animals, only a hundred survive in Asia, in a tiny wildlife park in the Iranian mountains.
Cheetahs have almost disappeared before. The modern 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.
Cheetahs are fast because they have to be: unlike most big cats, they hunt during the day, climbing termite mounds to spot stray antelope or gazelle. The black ‘tears’ under their eyes are thought to cut down glare and they have a wide, super-sensitive stripe on their retinas that gives sharp focus across the entire width of their vision, allowing them to chase and turn with near perfect accuracy. Anything within a 2-mile radius is in trouble.
Ancient Egyptian tombs show paintings of the cheetah, which was revered as a god. Cheetah heads are even carved into Tutankhamun’s funerary bed.
Only a handful of cars can reach 60 mph faster than a cheetah and none can do it on grass. But they have to be quick. Unless the antelope is caught within thirty seconds, the cheetah will overheat. They kill by strangulation. Their teeth aren’t as long or as sharp as a lion’s or a leopard’s but their bite is more powerful, crushing the windpipe and blocking the airflow. If successful, it then has to bolt its food, leaving behind the skin, bones and intestines. An adult can take on board up to 30 lb of flesh in a sitting (equivalent to an adult human polishing off six legs of lamb) and survive on it for five days. Lions, vultures and hyenas steal half of all kills but cheetahs don’t argue.
BUILT TO SPRINT
They know a single injury to their ‘fit-for-purpose’ body will doom them to starvation.
A female cheetah will sometimes bring back a live antelope calf to train her offspring. Cubs start hunting at eighteen months and, untrained, will often chase after completely inappropriate prey like buffalo.
‘Cheetah’ is originally a Hindi word, chita, which comes from the Sanskrit, chitraka, meaning ‘speckled’. There was confusion for a long time between cheetahs and leopards. When a medieval writer uses ‘leopard’ he usually means a cheetah. They were believed to be the illegitimate offspring of lions (which have manes) and ‘pards’ (which were spotted). Cheetah cubs do have manes (it helps camouflage them in grass). Their Latin name, Acinonyx jubatus, means ‘fixed-claw with a mane’.
Cheetahs can purr, chirp and yelp, but they can’t roar.
In ancient Egypt, India and Persia, cheetahs were trained to hunt by humans. Rewarded with butter and taught to recognise fifteen vocal commands, they were taken out on horseback, wearing hoods like falcons, and then set after antelope.
They are notoriously difficult to breed in captivity because the female needs to be chased by several males before she can ovulate. The sixteenth-century Mughal emperor, Akbar the Great, kept over a thousand cheetahs but managed only one litter. The next cheetah born in captivity wasn’t until 1956.
Chimpanzee
The thinking man’s ape
It is almost impossible to discuss the history of our nearest living animal relative without talking about ourselves. In 2002, a series of British TV adverts featuring chimpanzees dressed as a family of humans ended after forty-six years – the longest-running advertising campaign of all time. Their undeniable charm was based on a fallacy: that chimpanzees are like cheerful, uncoordinated human children. The irony is that the opposite is probably closer to the truth: that humans are chimps who didn’t grow up. We got smart instead.
‘Chimpanzee’ is from the Bantu kivili-chimpenze, meaning ‘mockman’. It was first used by Europeans in 1738, although sixteenth-century Portuguese explorers called them ‘pygmies’.
Adult chimps (Pan troglodytes) may not be much taller than a ten-year-old but they weigh twice as much and have five times the upper body strength of an adult human. Chimps can recognise themselves in a mirror, vocalise and use sophisticated gestures to communicate. Young chimps laugh when playful or being tickle
d. They appear to express emotions. They don’t have the physiology for speech, but they can learn some human sign language – though without grammar or syntax. They can use a variety of tools – some ‘fish’ for termites with twigs; others crack nuts with rocks or sharpen spears with their teeth. They learn from one another. To this extent, different groups of chimps have their own ‘cultures’.
In particular, their sister species the bonobos (Pan paniscus), only identified in 1929, seem to approach the common problems of food distribution and reproduction from a much jauntier angle. Whereas chimp groups are run by a team of dominant males, bonobos are like a feminist hippy collective, with sexual contact – male-female, female-female, adult-child – used as the universal social solvent. Anything that arouses the interest of more than one bonobo results in sex. Unlike common chimps, bonobos often have sex face to face; like them, the males have huge testicles, because the females of both species are serially promiscuous. It’s a sperm war: the more sex, the more partners, the better chance of raising your own offspring.
All of this fascinates us, and why shouldn’t it? Here are two species, closer to us than they are to the gorillas and with whom we share all but 1.5 per cent of our genetic material, whose behaviour is both like and completely unlike our own. But chimps and bonobos are no mere pit stops on the way to becoming human. Since our paths split from a common ancestor 5 million years ago, the genomes reveal that chimps have ‘evolved’ more than we have (meaning that more of their genes have changed as a result of selective pressure than ours). Also, they are much more genetically diverse than humans, suggesting that they were once common and we were rare. Whatever small genetic shifts allowed us to stand on our hind legs, freeing our hands to pinch and grip, and our brains to grow, it isn’t a lack in the other species, just a difference. And, as Darwin once expressed it, a difference of degree, not of kind.
There are fewer than 200,000 chimps and bonobos left in the wild. The start of their decline predates human intervention, but we haven’t helped: more are eaten as bushmeat each year than are kept in all the world’s zoos. Imagine a world without chimpanzees. It’s precisely because we can, and they can’t, that we should save them.
Cicada
An insect that counts
Nobody really understands how they do it, but some species of cicada match their yearly life-cycles to large prime numbers, that is, numbers that can only be divided by themselves and one: 2, 3, 5, 7, 11, 13, 17, etc.
‘Prime-number cicadas’, or magicicadas, from the Greek magos meaning ‘magician’, are only found in the eastern United States and their nymphs spend years below ground feeding on tree roots. They only reappear to mate every thirteen or seventeen years.
The reason for this mathematical precision is to avoid even-numbered (and therefore predictable) breeding cycles, which their predators could match. By ensuring that trillions hatch on a single evening, but at unpredictable times, they literally swamp their predators, who gorge themselves until they can’t face any more, without damaging the cicada population. There are thirty different broods, each of which is timed to hatch at a different time. The thirteen- and seventeen-year cycles only coincide once every 221 years.
In their long underground imprisonment, the larvae use their droppings to create waterproof cells, to help protect them from flooding. Even so, an estimated 98 per cent perish before they feel the urge to hatch. Those that do survive slough off their childhood form and mate furiously. Most are dead within a fortnight, providing a huge nitrogen boost for the forest floor.
CICADA HI-FI
Australian cicadas include the Green Grocer, the Floury Baker, the Double Drummer, the Cherry Nose and the Bladder.
Cicadas are easily the loudest insects, but it is only the males who ‘sing’ and usually only on warm summer days. Some species hit 120 decibels, equivalent to standing in the front row of an AC/DC concert. They can be heard nearly a mile away. Cicadas don’t rub their legs like grasshoppers, but make a series of clicks by buckling a pair of membranes, called tymbals, in their abdomens, in the same way we play a wobble board. Their bodies amplify the vibrations.
They often sing in large groups, which makes it impossible for birds to locate individuals, but the main function of the song is to attract a mate (although some have a ‘protest song’ which they use if you prod them). Each species has its own distinctive set of calls, which the females’ ears tune into.
The nineteenth-century French entomologist Jean-Henri Fabre tried to demonstrate that cicadas were deaf by firing a cannon towards a tree full of them. Their song didn’t change, but not because they were deaf. The sound of the cannon was meaningless to them: you can’t mate with heavy artillery.
Because of their apparent ability to be ‘reborn from the ground’ cicadas have come to represent resurrection and immortality in many cultures. In Taoism, they are symbols of tsien, the soul which leaves the body at death.
In ancient Greece, they were kept as pets. Plato tells a story of how they were once men whose devotion to music was so great that they wasted away, leaving only their music behind. Aristotle, on the other hand, was fond of eating them fried. Cicadas are still eaten across Asia and Africa and in Australia. Native Americans deep fry them and eat them like popcorn. They are surprisingly meaty and taste like asparagus.
Comb Jelly
Gooseberries with lovely eyelashes
Around 550 million years ago, animal life came in just four varieties: worms, sponges, jellyfish and comb jellies. The worms splintered into many different branches but the sponges and the jellies have changed little.
Early naturalists couldn’t decide if they were animals or not, so Linnaeus compromised by grouping them together as zoophytes or ‘animal plants’. Comb jellies are particularly plant-like to look at and their common names – sea gooseberry, sea walnut, melon jelly – have a distinct fruit & veg flavour. But they are unquestionably animals, and carnivores at that – gobbling up crustaceans, small fish and one another with what looks like single-minded dedication. Yet they have no brain – and no heart, eyes, ears, blood or bones, either. They are just a lot of mouth.
Most comb jellies are spherical or bell-shaped, ranging in size from no wider than a matchstick to longer than a man’s arm. 95 per cent of a comb jelly is water; the rest is made of mesoglea (‘middle glue’), a fibrous collagen gel that acts as muscle and skeleton rolled into one. To the casual observer, they look a lot like jellyfish: in fact the two are from completely different phyla and about as closely related to each other as human beings are to starfish.
Comb jellies are one of the ocean’s most ethereal sights. The beating of the cilia diffracts the light, making the combs look like eight shimmering rainbows.
The comb jelly phylum is called Ctenophora (pronounced ‘teen-o-fora’) from the Greek ktenos, comb, and phora, carry. Unlike jellyfish, which propel themselves by contracting their bodies, ctenophores move by rhythmically beating their eight ‘combs’ – rows of many thousands of hair-like cilia (Greek for ‘eyelashes’). Also unlike jellyfish, comb jellies don’t sting. Instead, they have long, retractable tentacles covered in colloblasts, special cells that exude sticky mucus to trap their prey. They also have anal pores (real jellyfish use their mouths as bottoms) which nestle next to a gravity-sensing organ called a statocyst that tells them which way is up. While jellyfish can regenerate a missing tentacle, half a comb jelly regenerates into a whole animal. Comb jellies also have a simpler reproductive system. Most are hermaphrodites, capable of producing eggs and sperm at the same time (up from the gonads, out through the mouth) and – theoretically – of fertilising themselves. They generally just release thousands of eggs and sperm into the water. Their young can breed as soon as they hatch.
Comb jellies are thought to be more numerous than any other creature of their size or larger. They aren’t great swimmers and are frequently swept into great, dramatic swarms, which pose a devastating threat to fishermen.
BEROE’S BLIND DATE
The collapse of commercial fishing in the Black Sea in the 1990s has been blamed on an American comb jelly, Mnemiopsis leidyi, that arrived as a stowaway in a US ship’s ballast tank. Now known as ‘the Monster’, it can produce 8,000 offspring a day. The Black Sea population weighs over a billion tons, hoovering up all the plankton that once fed the local anchovies. ‘The Monster’ has also invaded the Caspian, threatening the caviar sturgeon. In 2001, a cannibalistic comb jelly, Beroë ovata, was introduced to hunt down and slaughter its beautiful but remorseless relative.
Coral
Sea skeleton
Corals share their closest family ties with jellyfish. It’s hard to imagine two more different-looking animals, but they are both members of the Cnidaria phylum (from knide, Greek for ‘stinging nettle’). Coral looks far more like a colourful, baroque relative of the seaweeds, but close examination reveals it as an animal, or rather a host of animals, as each frond is composed of thousands of tiny individual ‘polyps’, rather like miniature sea anemones (another relative). Each polyp has a fringe of stinging tentacles, a bottom-cum-mouth, and a stomach, just like their cousins. But they do something that the others don’t: they build reefs, the rainforests of the ocean.
Coral doesn’t age as we do; most of its cells are the equivalent of stem cells in a developing human embryo, allowing even a small fragment to regenerate into a whole polyp. Some polyps may be over a century old.