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NC3Rs | 20 Years: Pioneering Better Science

How many animals are used in research?

In Great Britain in 2022, 2.76 million procedures were carried out involving living animals. Mice, fish, birds and rats account for 96% of this figure but other animals, including dogs and monkeys, are also used.

In this context, the term procedures means:

  • Using animals in scientific studies, such as experiments to increase scientific knowledge, medical research and safety testing (see How are animals used in research? for more details).

  • Breeding animals whose genes have mutated or been modified – these animals are used to produce genetically altered offspring that are used in research, rather than being used themselves.

The actual number of animals used is lower than the number of procedures because individual animals may undergo more than one procedure.

A graphic indicating the change in number of procedures performed on animals in Great Britain between 1996 and 2022.
Source: Annual Statistics of Scientific Procedures on Living Animals Great Britain 2022.

How has the number of procedures changed?

The annual number of procedures decreased in the late 1990s, hitting a low of 2.62 million in 2001. After that, the number increased again, then remained around 4 million with some year-on-year fluctuations until 2020, when the COVID-19 pandemic reduced the overall amount of research being performed. The annual figures are also affected by factors such as global research trends, the development of new technologies and the research funding climate.

What about the rest of the world?

It is hard to get an accurate figure for the number of animals used or procedures performed worldwide because other countries collect this data differently and some do not collect it at all. In the European Union (plus Norway), the latest available data is for 2020, when just over 8.6 million animals were used. In the USA, the reported number of animals used in 2021 was just under 1 million, but this figure is a huge underestimate because it does not include mice, rats, fish and birds.