The pain of animals used in research

In the service of our curiosity or our self-interest, we imprison, cut, burn, blind, or poison millions of animals in experiments. In the United States, the suffering of a small fraction of these animals is regulated by the Animal Welfare Act (AWA), passed in 1966. Later amendments established additional standards meant to reduce pain and distress suffered by the animals covered by AWA. As part of the process set up for the enforcement of these amendments, research facilities are required to report the number and the species of animals used in their experiments, whether the animals suffered pain and distress and whether pain-relieving drugs were administered. The most recent year for which USDA has made its data available is 2009.

As self-reported by the research facilities, a total of 979,772 animals covered by AWA were used in experiments in fiscal year 2009 (this number does not include animals held in the facilities but not yet used in experiments). The following pie chart shows the distribution of these animals by species/category. Rabbits, guinea pigs, and hamsters make up most of these animals (rats and mice used in research are not covered by the AWA).

Animals covered by the Animal Welfare Act and used in experiments in 2009
Raw data source: APHIS (USDA), Fiscal year 2009 Annual Report Annual Usage (pdf)

Now, what about their pain? The following bar graph depicts the percentage of these animals that were self-reported by the facilities as having been used in experiments that involved pain and distress. For reasons I do not know, pigs and sheep are most likely to be used in experiments that involve pain (over 57% of farm animals used in experiments are pigs, and over 13% are sheep). Over 75% of pigs and over 65% of sheep are used in experiments that involve pain. Guinea pigs and hamsters fare worse; they are most likely to be used in experiments in which the pain and distress caused to them are not alleviated by anesthetic or pain-relieving drugs.

Percentage used in experiments involving pain and distress
among animals used in 2009
Sources cited
  1. Transportation, Sale and Handling of Certain Animals (Animal Welfare Act). United States Code, 2009 edition, Title 7, Chapter 54. (link, accessed January 1, 2013)
  2. USDA, Animal and Plant Health Inspection Service. Annual Report: Animal Usage by Fiscal Year (2009). February 2011. (link, accessed January 1, 2013)

The fact that these are self-reported figures makes these the lower bounds rather than the actual numbers. For example, we can say that at least 40.4% of the primates used in experiments were used in those that caused pain and distress. But we cannot be sure if it was only 40.4%. After all, an obesity researcher who imprisons monkeys for decades in caloric restriction experiments is not likely to report that he is causing pain and distress. The agony of lifelong loneliness and confinement in a steel cage, unfortunately, does not quite count as pain and suffering in our minds prejudiced against other species.

Further, no grain of salt is large enough to take with the claim that most pain caused by experiments is actually relieved by drugs. How many of us would be willing to trade places with this monkey in this video if we were promised pain-relieving drugs? And, how about the monkey mentioned in this video who wakes up but a second dose of anesthesia is not given? Would a research facility report this monkey’s case under “with pain, with drugs” or “with pain, no drugs?” The self-reported numbers in this blog post are useful to know, but, sadly, it is doubtful that they tell us the full story.



It is very disturbing to see that such a large percentage of animal experimentation involves pain. What's worse is that, as you said, this is a self-reported number, which is most likely lower than the actual number. And even worse is that most animals used in experiments aren't even required to be reported. I am horrified to think of the suffering shown in the video happening to so many animals.

Have Gone Vegan

I too am horrified. And while I know that quantitatively most animal suffering and death occurs with animals used for food, there's something about animal research and experimentation that makes my blood boil just as much.

Barbara Rintrona

This is horrible what they are doing to animal's, they feel pain and it is not right and it has to stop !!!

karin van voorst

animals and humans are not the same! we react different to everything, so why do this tests on animals find volunteers in child abusers rapists etc...
maybe when they pay enough people they come out of themselves


It's so sad that pigs are the most tortured when they are the fourth most intelligent animal in the world. They are such a sensitive, intelligent species and yet people for some reason fail to recognize their worth :( I love pigs. It's also horrible to see that guinea pigs and hamsters are tortured so frequently without drugs. Why can people not realize that pain is pain regardless of species?

jeevraj jangid


Aryenish Birdie

Thanks for this post :)

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