Wild wisdom

But if we're so delicate, how did we fare long before the 'invention' of medicine? And how come wild animals manage to get by - even thrive - without a health service?

Stories about animals healing themselves with natural remedies have been around since antiquity. The Navajo indians of North America called the lingusticum plant 'bear medicine' after watching sick wild bears dig up the roots, while in Europe herbalists called one particular species of grass 'dog grass' after seeing how sick dogs turned to eating it.

North American pioneers are even thought to have developed folk medicine by studying the plants sick animals made use of.

Until recently, hard-headed scientists dismissed the stories. But now a new book by animal behaviourist Dr Cindy Engel reveals that wild animals make use of an astonishing range of behavioural strategies to stay healthy.

And in Wild Health, she suggests we could learn from some of them ourselves.

Many animals, for example, display an instinctive 'nutritional wisdom' that we seem to have thrown out along with our junk-food wrappers. Rats offered a range of cafeteria-style foods will naturally select a nutritionally-balanced diet. Wildebeest on the Serengeti Plains in Africa migrate south after calving so they can graze on grass growing on ash-rich soils at the foot of volcanoes. The ash contains calcium and phosphorous essential to healthy milk. And African chimpanzees suffering from the runs have been observed breaking off walnut-sized pieces from termite mounds and popping them into their mouths. The mounds, it turns out, are rich in a clay that can absorb poisons and so makes a good natural medicine for diarrhoea.

Clay-eating is actually common in the animal kingdom, Dr Engel says - everything from giraffes, elephants, monkeys and rhinoceroses to birds and rodents eat it when they feel sick. Even more astonishing, they invariably eat the right type of clay, digging below the surface of the soil, which is full of harmful bacteria, to find 'clean' clay beneath.

When it comes to bacterial infection, we humans have one simple response: start popping antibiotics. That's fine in the short-term: but problems with new strains of super-resistant bacteria that have developed in response to our medicines are now common knowledge.

Animals' strategies for dealing with infection may in the long-term be more sensible. First of all, they try to avoid picking up infections in the first place. Many animals' standards of hygiene would put some of us to shame, Dr Engel points out. Worker honey bees toil tirelessly to keep the nursery cells where young are growing clean, for example: while chimpanzees scrupulously clean themselves if they get soiled with excrement, urine or blood.

If they do become infected, meanwhile, animals have a range of strategies to boost their chances of recovery - from fasting to reduce the amount of iron in the blood that bacteria rely on, to eating fruit, bark and seeds that are rich in natural 'antibiotics' known as antimicrobials. Even insects make use of them: Gall wasps, for example, lay their eggs near leaves that are high in tannin, a natural antimicrobial, thus giving them the maximum natural protection against infection - a classic case of prevention rather than cure.

"While we humans focus solely on the destruction of pathogens," writes Dr Engel, "animals combat infectious disease via a holistic approach that involves avoidance, prevention and treatment of symptoms."

Animals may even have strategies for coping with broken bones or deep wounds. Biologist Lyall Watson, Dr Engel reports, once heard of a mountain goat that made itself a poultice of clay and lichen and applied it to the wound. Some kinds of bird may even do the same. The jury on that one is still out, she admits. But people can learn much from animals.

Even in the midst of plenty, she points out, many people manage to be malnourished; largely because the food industry supplies us with what we want, not what our bodies need.

We evolved as hunter-gatherers: a lifestyle that needed lots of high-energy food to give us strength for hunting and gathering.

There were never enough high energy foods around, so we always craved them. We craved sweet foods because they meant lots of short-term energy: fatty foods because they allowed us to store energy against a rainy day. That craving is built into us. Originally, in our search for such foods, we ate a balanced and varied diet - as well as burning off many of the calories we consumed.

The problem is, today's modern food industry is good at satisfying our cravings for sweet, fatty foods without providing the vitamins, minerals and fibres also vital for our long-term health.

We're not the only ones to turn into instant couch potatoes given the chance, Dr Engel concedes. The baboons of the Masai Mara game reserve in Kenya used to live a very healthy lifestyle, foraging for food much like our own ancestors. The growth in tourism, however, has led to a new phenomenon: rubbish dumps full of the junk left behind by tourists.

Baboons quickly cottoned on that they didn't need to spend all day foraging. "They could lie in bed till the waste truck arrived, binge on high-sugar, high-fat, high-protein junk-food leftovers, then relax all afternoon."

The result; a generation of overweight baboons with sky-high cholesterol and insulin levels.

Sound like anyone you know?

- Wild Health is published by Weidenfeld and Nicolson, at £20

Updated: 10:15 Tuesday, February 12, 2002