Imagine an educational institute that has more than 1,000 learning centres spread across the world, and more than 600 million students from every conceivable background. Add to this the most powerful of all teaching aids - living wild animals - and you have the largest provider of environmental education on earth: the global network of zoos.

The modern zoo has four main roles: conservation, education, entertainment and research. The original function of a zoo was as a centre for taxonomic (classifying) research. For the first 20 years of its existence, London Zoo, which opened in 1826, was only open to bona fide scientists. For more than 100 years, zoos have been places of public entertainment and even today, the vast majority of people visit zoos for a “fun day out”.

However, over the past few decades, zoos have matured into centres committed to saving endangered species from extinction, through their captive breeding programmes. It is for this reason that there are still Przewalski’s horses, California condors and P re David’s deer. Captive breeding in zoos is also creating safety-net populations for highly endangered species such as the Siberian tiger. But to be really effective, zoos need to do more than this; they need to educate their visitors.

A good zoo recognises that visitors are a captive audience too and need to be educated in a variety of formal and informal ways. This can take the form of guided tours, public talks, information signs, guidebooks, animal handling classes and lessons.

Teachers contemplating a school visit to a zoo will find that they can book a wide variety of lessons that teach anything from monkey behaviour to sex education. These lessons have been developed by qualified teachers and are linked to national curriculum requirements and tailored to specific age-groups. For instance, primary groups could be involved in activities such as drawing and role playing, whereas more senior groups might perhaps have a more structured debate. All lessons emphasise different learning strands, such as language skills.

Edinburgh Zoo’s most popular lesson (with more than 5,000 pupils annually) is entitled “Cycle of Life”, and links up with the study modules Living and Growing and Sex Education. This is aimed at nine- to 13-year-olds. The lesson starts with a slide show that illustrates courtship, mating, birth and variations in child-rearing in a variety of different species. Each topic area allows pupils to make references to human behaviour. The slide show is followed by a guided tour of the zoo, which gives a complete sensory experience of seeing, hearing and smelling wild animals - something that a video, however vivid, can never do.

The way in which an animal is exhibited affects its educational value. Animal enclosures in modern zoos are designed to allow their inmates the chance to express most of their natural patterns of behaviour. This is vital in ensuring that zoo animals experience a good standard of welfare, as well as being something that people can learn from. Ideally, animal exhibits should be naturalistic - they should look like the environment from which the animal actually comes. This means that a visitor can make the important link between an animal and its natural habitat. Research has shown that animals exhibited in barren enclosures elicit feelings of pity and disgust from visitors, whereas those in naturalistic environments arouse appreciation and respect, a much more positive response in every sense.

Zoos use what is known as environmental enrichment to ensure that the animals they house enjoy a high standard of welfare. This is essentially a method of giving them something to do which is not only biologically relevant but fun for them. For example, wild chimpanzees will spend ages “fishing” for termites by shoving sticks into termite mounds, which the termites bite and hang on to. The chimpanzee then licks the termites off the stick. Edinburgh Zoo has provided its chimpanzees with an artificial mound from which they can “fish” for yoghurt. This type of activity is a powerful educational tool, not only because the animal is doing something it enjoys, but also because the action will attract the attention of passing visitors, who will then spend time watching and learning from it.

One of Edinburgh Zoo’s policies is to recycle as much as possible; a good zoo should strive to be as “green” as it can, in everything it does. This has been extended to the environmental enrichment programme by making puzzle feeders for the primates from packaging material from goods delivered to the zoo shop. This combines conservation with a concern for animal welfare.

Edinburgh Zoo’s education officer, Anne Gallagher-Thaw, takes this a step further in her children’s workshops which make environmental enrichment devices for monkeys and parrots. The children are given a range of household materials (in a room that looks like a giant Blue Peter set) and allowed to make something that they think a monkey or a parrot would like to play with. Once these have been constructed, it’s a case of sit back and watch as the keepers put them in the animals’ enclosures. It is a particular cause for excitement if the animal plays with your toy first. These workshops are great fun for all concerned but most importantly they teach children about animal welfare, conservation and recycling in an extremely powerful way.

Not all zoos undertake all the activities described above but they all have the potential to do so. It is up to individual zoos to realise their educational potential, which is nothing short of a living, breathing, global classroom.

* Dr Rob Young is the research co-ordinator for the Royal Zoological Society of Scotland.

* Edinburgh Zoo Royal Zoological Society of Scotland, Murrayfield, Edinburgh EH12 6TS.Tel: 0131 334 9171

ANIMAL MATTERS AT THE EDUCATION SHOW

* Royal Society for the Protection of Birds stand PV20

* Tusk Force stand PV284

* Worldwide Fund for Nature stand PV184

* The Federation of Zoos stand SJ23

* Animal AidLeague Against Cruel Sports stand J44

* Chessington World of Adventure stand J30