The vastly varying ways in which animals copulate is always extremely fascinating. Male damselflies, for instance, have little microscopic spines on their phalluses which they use to scrub out pre-existing ejaculations of former mates of a particular female, to ensure their own sperms (DNA's) success. Then there is also the strange cork-screw shaped male duck phallus that was written about in a NyTimes article a few months back, found here.
But just today an even stranger animal, the spiny anteater, has had its reproductive methods and in particular phallic structure exposed by the intrusive eyes of scientific inquiry for the greater good of the public's mirth. Courtesy of NewScientist:
By filming this animal, the researchers have been able to describe the unique spiny anteater erection and ejaculation behaviour for the first time.
The spiny anteater's four-headed phallus had been puzzling scientists. "When we tried to collect semen by [electrically-stimulated ejaculation] before, not only did we not get a single drop, but the whole penis swelled up to a four-headed monster that wouldn't fit the female reproductive tract, which has only two branches," says Johnston.
“Now we know that during a normal erection, two heads get shut down and the other two fit," he told New Scientist. The heads used are swapped each time the mammal has sex.