Yesterday, i surf internet to "en.wikipedia.org" I found a interesting about animal's sex intercourse. A pair of lions copulating in the Maasai Mara, Kenya. Sexual intercourse for most non-human animals occurs at the point of estrus (the most fertile period of time in the female's reproductive cycle), which increases the chances of successful impregnation. However, bonobos, dolphins, and chimpanzees are known to engage in sexual intercourse even when the female is not in estrus, and to engage in sex acts with same-sex partners. In most instances, humans have sex primarily for pleasure.This behavior in the above mentioned animals is also presumed to be for pleasure, which in turn strengthens social bonds.