Justin Bieber has been urged by a German animal shelter holding his pet monkey to "do the decent thing" and put the pet up for adoption.
The capuchin monkey was seized by German customs earlier this month when the 19-year-old singer failed to produce the necessary customs documents after landing in Munich for his European tour.
Bieber - who left Mally in quarantine at a Munich animal sanctuary and returned to Los Angeles to perform more shows - was given a deadline of four weeks to collect his monkey, or it would be placed in permanent care. But this has now been extended indefinitely while his management completes the paperwork.
But animal shelter boss Karl Heinz Joachim, 64, warned Mally could suffer mental damage if it spent months in quarantine, and it needs the company of other monkeys.
The monkey was given to Justin for his 19th birthday last month from music producer Jamal 'Mally Mal' Rashid. He had been taken away from his mother when he was only nine weeks old. Normally capuchin monkeys remain with their mothers for at least the first year of their life.
Joachim told MailOnline: "The baby monkey needs company and to be with other monkeys at this crucial age in its life.
"We'll appeal to the star to do the decent thing and let the monkey be free for adoption.
"There are a great many suitable places that have offered to take Mally and integrate him with their own capuchin monkeys where he would be much more happy with his own kind.
"A baby monkey is not something suitable to be on a world tour even if he is travelling by private jet. He should be out in the wild climbing trees and learning from other monkeys if he isn't to have serious psychological problems later in life."