The RSPCA has called for a ban on primates as pets.
The animal welfare organisation said the recent quarantine of Justin Bieber's capuchin monkey highlighted the problems of keeping these "highly social, intelligent animals" as pets.
Dr Ros Clubb, senior scientist for the RSPCA, said: "Many people see monkeys like capuchins and marmosets as small and easy to keep but this is far from the truth – they are very hard to look after and totally unsuitable as pets. They can also be dangerous."
Dr Clubb said it would be "totally unacceptable" if media reports alleging the monkey was taken from its mother a very young age and kept on its own were true.
However he added that this was "not an unusual occurrence".
The charity reports increasing numbers of cases involving the suffering and neglect of primates. It blames this on poor regulation and the online trading in primates making it difficult to monitor how they are being looked after by their owners.
Dr Clubb continued: "When deprived of their mother and kept alone rather than in the family groups they belong in, many self-harm, become aggressive and suffer many problems later in life. Primates kept as pets can develop crippling cases of metabolic bone disease due to a lack of vitamin D they would normally get from a healthy diet and the sun.
"We must stop this practice. Breeders and dealers charge large sums of money, and it has become far too easy to pick up a monkey over the internet, especially since many of the most commonly kept species, like marmosets, don't need a licence to be kept."
Between 2001 and 2010 there were 472 calls about pet primates to the charity's cruelty complaints line mostly concerning marmosets and capuchins.
- Last July Peter Powell, from Plymouth admitted to neglecting two pet marmosets which he kept in dark and filthy conditions and put in his pocket as he drove around town on his mobility scooter. The animals had been found living in appalling conditions. A razor blade, cigarette butts and faeces was scattered across the floor and there was no evidence of the specialised food or perching room necessary for their care.
- In January 2012 Lee Powell and Julie Ann Jones from Stourbridge were found guilty of causing suffering to Mikey the marmoset. Mikey had seven fractures in his legs due to metabolic bone disease, the result of lack of vitamins in his diet and lack of exposure to sunlight. This meant he could only shuffle along the floor and sadly, he had to be put to sleep.
- In February 2011 Patricia Wilson and Duncan Johnson, from Gateshead, pleaded guilty to not providing adequate care to their marmoset, Marley, which they kept in a parrot cage on his own and gave him rides on the family dog's back. The couple claimed to love their pet, but be unaware of his needs.