A new study has found that 35 per cent of men from rural Brazil have had sex with an animal.
A total of 492 men took part in the study ranging in age from 18 to 80 years old.
A team of urologists from centres around Brazil were involved in the research project, which looked at risk factors for penile cancer in men.
And it found that men who had sex with animals during their lifetimes were twice as likely to develop cancer of the penis as others.
Those who had engaged in bestiality also reported a higher incidence of sexually transmitted diseases.
Of the 492 men who took part in the study, 118 were penile cancer patients.
A total of 45 per cent of those suffering from cancer told how they had had sex with an animal.
This was compared to 32 per cent of healthy men.
A total of 59 per cent of men who had sex with animals did so for one to five years, while 21 per cent continued the behaviour, also known as zoophilia, for more than five years.
The subjects reported a variety of frequencies for their sex acts, ranging from monthly to daily.
The researchers found no association between penile cancer and the number of animals the men used over time.
The species included mares, cows, pigs and chickens, among other animals.
Lead author was Stjnio de Cassio Zequi, a urologist in Sao Paulo, and he said his study is the first to link the practice to male genital cancers.
He told LiveScience that if a man has sex with an animal it could produce micro-traumas in the human penile tissue.
‘The genital mucus membranes of animals could have different characteristics from human genitalia, and the animals’ secretions are probably different from human fluids.
‘Perhaps animal tissues are less soft than ours, and non-human secretions would be toxic for us.’