Mark Carwardine - Extreme Nature

Like its close toad relatives, the holy-cross also has unique glands in its skin. If it is disturbed or distressed, these release a special secretion that turns into glue. The glue hardens in seconds and has a tensile strength five times that of other natural glues. This is particularly useful should ants attack, as even the biggest immediately get stuck to the toad’s skin. And since, like all frogs and toads, it sheds its skin and eats it about once a week, the holy-cross toad has the pleasure of swallowing the ants that attack it.

Scientists in Australia are now trying to produce an artificial glue as good as the toad’s. Holy-cross toad glue will stick plastic, glass, cardboard and even metal together. More importantly, it can repair splits in cartilage and other body tissues and therefore might prove to be a miracle adhesive that will help surgeons repair the most difficult of injuries.

© Haroldo Palo Jr/NHPA

The castor bean plant produces possibly the most deadly plant toxin, 6,000 times more deadly than cyanide, but it has also been known for thousands of years as a wonder plant. The secret and the poison both lie in the seed. More than 50 per cent of it comprises a rich oil, but to protect it from being eaten is ricin, a protein toxic to almost all animals (lesser quantities of ricin occur in the leaves). The poison, once ingested, inactivates the key protein-making elements of a cell without which it can’t maintain itself and dies.

For humans, death is prolonged, ending in convulsions and failure of the liver and other organs. There is no known antidote. The most usual cause of poisoning comes from accidentally eating seeds, but ricin can be administered in aerosol form, in food or water, or injected, as in the famous case of a dissident Bulgarian journalist. While waiting at a bus stop at Waterloo station in London, in 1978, Georgi Markov was murdered by being stabbed with an umbrella that injected a pellet containing ricin. Widely available and easily produced, ricin could be used for biological warfare.

It is equally easy to extract the seed’s valuable oil, however, which has been used for at least 4,000 years as a lamp oil and soap and also as medicine for a huge array of ailments. Today its uses include high-grade lubricants, textile dyes, printing ink, waxes, polishes, candles and crayons. In the future, its array of protective chemicals may even provide a cure for tumours.

© Werner A Wuttke

No, the biggest blood-sucker isn’t a vampire bat. Vampires, which are native to the tropical Americas, don’t actually suck blood – they lap it up. They find large mammals – most noticeably cows, pigs or horses – make a cut in their skin and then drink the blood. Not being very big (average body length is 6.5–9cm/2.5–3.5in), a single bat only actually consumes a few tablespoons of blood a night, though because of the anticoagulant in its saliva, the prey keeps bleeding for some time after the bat has flown away.

The world’s largest leech, measuring up to 46cm (18ins) does suck blood, however, and a very hungry one can take in four times its body weight before it becomes satiated. Since a large Amazon leech weighs about 50g (1.8oz) – the record is 80g (2.8oz) – that’s a lot more than a few teaspoons of blood. Like the vampire, the Amazon leech feeds on large mammals, which it attacks when they enter water, and it also uses an anticoagulant to keep the animal’s blood flowing. But the leech injects an anaesthetic, too, so that the temporary host is unaware of what’s happening to it.

All leeches are segmented worms – their nearest relatives are earthworms – and all, regardless of size, have precisely 32 segments. A few segments at each end of the Amazon leech are modified into suckers for attaching to prey, and every segment has its own independent nerve centre – hence a leech has 32 brains.

© Jeff Lepore/Science Photo Library

Many animals rely on their sense of smell to find food or a mate and even to find their way around. Some live in places where other senses are of little use – eyes don’t help much if you spend most of your life in the dark, and ears would be hopeless in a particularly noisy environment – so they rely on smell more than most.

Some animals, such as sharks, are selective in their smelling abilities and are super-sensitive to significant smells that are relevant to activities such as feeding or breeding. In fact, smell is so important to sharks that they have been dubbed ‘swimming noses’. Their smell receptors are fine-tuned to picking up small concentrations of fish extract, blood and other chemicals – but so are the receptors of many other animals. Some catfish have such super-receptors that they can smell compounds at 1 part to 10 billion parts of water.

The likelihood is, though, that moths are the record-holders, especially the males. They use their antennae to home in on the sex pheromones, or chemical allures, released by females and can even detect if these females are on plants suitable for egg-laying. Some females release deviously small amounts of pheromone, to make sure that only those males with the most highly tuned antennae can follow the trails. The likely record-holder for the best known sense of smell is the polyphemus moth: just one pheromone molecule landing on a male’s antennae will trigger a response in his brain.

© Flip Nicklin/Minden Pictures/FLPA

Drop a hydrophone into the water in an area where humpback whales are breeding and you may hear a baffling medley of moans, groans, roars, snores, squeaks and whistles. These are the hauntingly beautiful sounds made by male humpbacks, which are famous for singing the longest and most complex of animal songs. Since most singing takes place at the breeding grounds, it is probably used to woo females and to warn away rival males – but the songs may also have more subtle meanings and nuances that we do not yet understand.