Asian female elephants go into heat once every four months for about two to three days. The females don't regularly mingle with males, so they let out a call when they're ready to mate. While she's fertile, the male and female will mate about five times a day, but the male won't penetrate the female. Rather, it will spray a quarter of a liter of semen at the female's vagina, an amount more than 100 times that produced by a healthy human man. Among other hurdles, the male sperm must swim 6.5 feet to meet the elephant egg. Human sperm, in contrast, swims 3 inches.
In the fetus, the elephant develops a unique mammalian feature called nephrostomes, or funnel-like ducts in the kidneys. These ducts can be found in freshwater fish and frogs, leading scientists to believe that elephants may have evolved from aquatic beginnings, when they used their trunks as snorkels. To wit: elephants can swim more than 15 miles without stopping by using their trunks to breathe.
Photo by Pioneer Productions
