#More than 100 million rats, mice used in US labs: report

Humans owe a huge debt of gratitude to lab rodents, but only now are we discovering just how many thanks are in order.

In a first for laboratory science, a new report has attempted to quantify how many rats and mice are sacrificed for the sake of research annually — and it’s staggering.

In terms of biomedical research alone, US labs rely on over 111 million mice and rats annually, according to the study by veterinary researcher and author Larry Carbone, now appearing in Scientific Reports. The two vermin make up 99% of the whole of common lab mammals.

Animal activists and science advocates are at odds over the new statistic, Science Mag reported Friday.

“If the numbers are anywhere near correct, the amount of pain and suffering that’s occurring in these animals is completely unacceptable,” said Sue Leary, president of Alternatives Research & Development Foundation (ARDF), who works toward reducing the number of animals in labs. Their own estimate was much less: about 23 million.

Rats and mice are not explicitly covered by the Animal Welfare Act (1966), Leary pointed out, which is enforced by the US Department of Agriculture (USDA). Prior to 2002, when Congress formally excluded certain animals from protection, the USDA declined to track most birds, rats and mice — meaning there has never been a US agency in charge of tracking lab rats and mice.

Meanwhile, critics are calling out Carbone’s bias. Nadia Rosenthal, director of Jackson Laboratory, called the analysis “fundamentally flawed” and “inaccurate and vastly overstated.” Jackson Labs has a stake in the lab rodent business as they provide such specimens for universities and other scientific institutions. Between Rosenthal’s lab and Charles River Laboratories, who run a similar operation, only about 20 million mice and rats are bred and sold in the US for research.

Allyson Bennett, a senior editor at Speaking of Research, are challenging the new study with their own assessment — somewhere between 10 million and 25 million. “It’s a really disappointing analysis,” said Bennett, whose organization supports the use of lab animals. Similarly, the National Association for Biomedical Research’s best guess is just under 15 million.

Carbone’s previous research supports his new report. While writing a book on the history of animal welfare policy in the early 2000s, he based his guess of 80 million to 100 million on his working experience at Cornell University and the University of California, San Francisco. He told Science Magazine his current study is the most comprehensive yet.

This time around, Carbone relied on public records from large scientific institutions — specifically lab inspection reports, which are required to count animal inventory. For private institutions, he leveraged his network of scientists from over four decades of research in the field, he told Science Magazine.

His findings also revealed that some 39,000 animals that are covered by the AWA, such as monkeys, dogs and rabbits, are used in research.

If Carbone’s estimates are accurate, it would mean the USDA is tracking just 0.7% of all animals used in labs.

“If we’re serious about reducing the number of lab animals we use and curbing the number of painful experiments, somebody has to be keeping track of these animals,” he concluded. “You can’t track progress if you can’t measure progress.”