Clutching the school guinea-pig or charting the growth of tadpoles in a jar has, for generations, been many children’s first encounter with the natural world.

But the practice of keeping animals in school is endangered and may even become extinct if RSPCA guidance is enforced.

Allowing small children, and even smaller creatures, to interact during lessons can be cruel, according to the animal welfare charity.

It says that the shrieks and grabbing hands of affectionate but boisterous pupils make the classroom a frightening and noisy place for pets. The health and wellbeing of animals can suffer even further if they are entrusted to children for the weekend, or over the holidays.

Soft toys in the shape of animals are a much better introduction to fauna, the charity advises schools. Its guidance has been e-mailed to 16,000 teachers and promoted at education events.

Recent research by the RSPCA found that more than a quarter of schools keep animals. Two thirds have fish, but the rest boast a bewildering array of creatures.

These range from hamsters, rats, rabbits and budgies to the more exotic water dragons, chinchillas and snakes to, in a few cases, cats, dogs, goats and a horse.

Some schools hatch hens’ eggs in an incubator so children can see the chicks grow. Others keep only fish because of fears about staff or children having allergies to furry animals.

A few have small farms or wildlife areas, but a lot of animals are kept in classrooms.

The RSPCA believes, however, that animal welfare can be taught in schools without keeping any creatures captive. Dave Allen, the charity’s head of education, said: “Welfare can be compromised. The school day is short — what happens to the animal the rest of the time? It can go from being loved to death to being left alone for the evening. Holidays and weekends are an even bigger issue. If the animal is going to different children each week the standard of care varies.”

Mr Allen said that schools keen to engage with wildlife should put up bird feeders or turn part of their playing field into meadow.

Even transferring the classroom tadpoles to a school pond is questionable. Mr Allen gave warning that ponds needed continued commitment. “We don’t have a problem with school farms, if they are managed well,” he said. “But the danger is, when keeping animals in the classroom, that the teachers are so busy the animals can become educational tools rather than sentient creatures. It is not giving the right message on animal welfare.”

The RSPCA’s guidance states: “Animal welfare can be taught in schools without keeping animals captive. Studying an animal in its natural environment should aim to cause minimal disturbance whilst maximising educational opportunity.

“Where animals are kept in schools, proper provision should be made for their physical and mental wellbeing.”

If schools are determined to keep animals, a named person must at all times be responsible for their welfare and husbandry, the guidance says.

“Contact between pupils must be supervised and controlled and animals should have adequate ‘rest’ periods away from disturbance,” it adds.

The charity is campaigning for animal welfare to become part of science or citizenship lessons.

Times recommends

• Screen tests are the future of exams
• No more free boarding schools for diplomats
• Popular Jewish School broke race laws