London, Feb 17 (ANI): Scientists based in Japan have revealed that chimpanzees produce 200 times more sperm than gorillas, the world's largest primates, and 14 times more than orangutans.
Promiscuous ape species have bigger testicles, and the new finding provides evidence that they also produce more sperm.
Earlier, scientists proposed that chimps have large testicles because several males mate with a single female, and so have to produce more sperm in order to compete.
For the latest study, scientists studied chimpanzees, orangutans and gorillas from zoos in Japan and Indonesia.
Analysing samples of testicular tissues at a microscopic level, researchers found remarkable variation between the apes.
They found that the sperm-producing tissue lining gorillas' testes was much thinner than that of orangutans and chimpanzees.
Chimpanzees were found to produce 14 times more sperm than orangutans and even more than the world's largest primates.
"Our data indicated that a chimpanzee usually produces about two hundred times more sperm than a gorilla," the BBC quoted explained researcher Hideko Fujii-Hanamoto as saying.
For these three species of ape, the scientists have now proven that testes size is proportionate to sperm production.
The researchers claim that these findings also support theories that sperm production relates directly to reproductive competition and mating behaviour.
The study has been published in the American Journal of Primatology. (ANI)