Hollywood has been taken to task over the 'unethical' use of apes and monkeys in movies.
A UK conservation expert claims film depictions of the animals, often 'smiling' or dressed in human clothes, are misleading and potentially harmful.
Grinning primates are often baring their teeth to show they are scared or 'suffering' in silence, according to the researcher.
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A UK conservation expert claims film depictions of the animals, often 'smiling' or dressed in human clothes, are misleading and potentially harmful. Pictured is a chimpanzee held by Leonardo DiCaprio in the 2013 blockbuster The Wolf of Wall Street
- The Hangover Part II (2011)
- The Wolf of Wall Street (2013)
- Babe: Pig in the City (1998)
- Night at the Museum (2006)
- George of the Jungle (1997)
- Ace Ventura: Pet Detective (1994)
- Outbreak (1995)
- Every Which Way But Loose (1978)
Brooke Aldrich, from the Peru-based charity Neotropical Primate Conservation, said more needs to be done to educate audiences and filmmakers about the 'unethical nature' of using primates in the movie industry.
She added that using primate actors 'trivialises' their conservation and welfare needs and represents them as suitable pets.
The researcher analysed two decades of English-speaking film trailers from 1993 to 2013 to investigate the roles played by primate 'actors'.
Primate 'actors' have been featured in several Hollywood blockbusters including The Hangover Part II, The Wolf of Wall Street and Babe: Pig in the City.
Ms Aldrich's findings show that more than half the time apes and monkeys were shown among people, frequently performing 'human' actions.
In many cases chimps and other primates were seen to be 'smiling', which indicates fear or submission.
Mr Aldrich said that it is