Other males may worry that losing their hair will make them less appealing.
But for Guru the chimpanzee, his baldness has turned him into a star attraction.
The 20-year-old, who is suffering from alopecia, has lost the hair from all over his body.

But the mischievous chimp still brings hundreds of visitors flocking to Mysore Zoo in southern India – despite greeting them by throwing stones.
Dr Suresh Kumar, a zoo vet, said: ‘Everybody wants to see his biceps and triceps.
‘He beats his chest, and claps a lot when children come near his enclosure.’
Guru had lost his hair before being rescued from a circus and moved to Vandalur Zoo in Chennai.
He lived there for almost a decade, but was transferred to Mysore Zoo seven years ago so that specialist vets could monitor his condition.
Dr Kumar said: ‘He came to us with alopecia, so we don’t know how he got it originally.


'However, with chimpanzees being so much like humans, we think it could have been caused by factors in Guru’s life such a stress or trauma, which can induce alopecia in humans. We have tried a number of medicines on him, but to date there have been no positive results, and as a last resort we are planning to consult a human skin doctor.’
Fortunately, Guru’s baldness doesn’t seem to have affected his popularity among his own species. To stop him getting lonely, zoo officials have allowed a female chimpanzee, Manila, to move into his enclosure.
But although Guru plays cheerfully with her, he hasn’t taken things any further – to the surprise of his handlers.
Dr Kumar said: ‘He got separated from his parents at a tender age and most probably this could be a reason that he hasn’t learned to mate.’