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In experiments

The most common monkey species found in animal research are the grivet, the rhesus macaque, and the crab-eating macaque, which are either wild-caught or purpose-bred. They are used primarily because of their relative ease of handling, their fast reproductive cycle (compared to apes) and their psychological and physical similarity to humans. Worldwide, it is thought that between 100,000 and 200,000 non-human primates are used in research each year, 64.7% of which are Old World monkeys,and 5.5% New World monkeys. This number makes a very small fraction of all animals used in research. Between 1994 and 2004 the United States has used an average of 54,000 non-human primates, while around 10,000 non-human primates were used in the European Union in 2002.