Almost 17,000 animals were used in medical experiments conducted by the University of Leeds last year – and most of them were killed.
A Freedom of Information request submitted by the Yorkshire Evening Post revealed the university has carried out experiments on 55,235 mice and 5,155 rats over the past five years.
Other animals subjected to scientific tests between 2007 and 2011 were pigs, sheep, bats, gerbils, rabbits, guinea pigs, toads, frogs, and birds.
A university spokesperson said the “overwhelming majority” of laboratory animals were killed at the end of procedures so their tissues could be examined.
However, animals studied in the wild – such as birds – or those in farm settings, were usually returned “unharmed” to their environment.
Last year, the charity Animal Aid held a demonstration in Leeds city centre over the university’s lethal experiments on dogs.
Its heart surgery research is thought to have claimed the lives of around 100 beagles.
However, no dogs have been used in medical research at the university for the past six years.
University veterinary officer Dr Khawar Abbas said: “In Leeds the last dog we used was in 2006.
“We are not using dogs for medical research at the moment and we currently have no plans to do so.”
Although thousands of primates are killed in the name of research every year, Dr Abbas, who has worked at the university since 2001 as well between 1982 and 1990, said to his knowledge they had never been used in Leeds.
He defended the number of animals used in Leeds, saying it would be comparable to that used by similar universities.
He added: “It all depends on the type of research they are doing.”
And he said the animals’ welfare was taken very seriously, with vets on hand 24 hours.
All prescription medicines available today have involved the use of animals in their development.
British law states that any new drug used for medicine must be tested on at least two different types of live mammal.
Many award-winning scientists claim they couldn’t have made their discoveries without animal testing.
Penicillin was tested on mice, as were vaccines for meningitis and polio.
A university spokesperson said its experiments on animals had led to better understanding of diseases and health problems including cancer, childhood leukaemia and heart failure, as well as obesity, drug addiction and pain management.
Alternatives include medical imaging, computer modelling, human volunteer studies and statistical studies.
But Dr Abbas said if their objectives couldn’t be achieved using the alternatives they would apply to use living creatures.
Research using animals is regulated by the Animals (Scientific Procedures) Act and carried out under licences granted by the Home Secretary, who is expected to balance the benefits of a project against likely cost to the animals’ wellbeing.
But in a move to integrate EU and UK laws, the Government plans to remove protection granted to stray domestic animals like cats and dogs.
Under the new rules, lost or abandoned pets could end up in a lab, being experimented on.
In 2011, 97 per cent of the creatures the University of Leeds conducted experiments on were mice.
Scientists rely on mice for many reasons, including size, rapid reproduction and the fact their genetic and biological characteristics closely resemble those of humans.
The number of larger animals used has dropped due to increasing use of genetically-modified mice.