Sex: A Monotreme's Four-Headed Monster

This latest news item courtesy of New Scientist a.k.a. the London tabloid of science journalism (1), is worthy of Bora's (Blog Around the Clock) Friday Weird Sex Blogging but what the heck - there's nothing more uplifting that a four-headed phallus on a Monday afternoon.

As noted in the article, Exhibitionist spiny anteater reveals bizarre penis, spiny anteaters (Tachyglossus aculeatus) ejaculate through only one half of their penis. This mechanism is similar to that of reptiles. Zoologists have wondered if monotremes might ejaculate via the same technique. Since the fine details of spiny anteaters' sex lives are difficult to observe in the wild and captive animals are none too keen on breeding, the whole- vs. hemi-ejaculate question was hitherto unresolved.

That is, until Steve Johnston and colleagues at the University of Queensland acquired the equivalent of a monotreme flasher. This particular spiny anteater that had been summarily booted from a touchy-feely look at the critter up-close exhibition because it became erect while being handled for public viewing. So Johnston et al. had a prime opportunity to study its penis.

Excerpted from the New Scientist article:

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.

This spunky evolutionary adaptation appears to be related to sperm competition. Multiple male spiny anteaters line up to copulate with a single fertile female.

One wonders if Johnston's spiny anteater still sports public erections now that its nether regions have been shocked into yielding a four-headed monster.

(1) Just some gentle snark. I am a longtime subscriber to the print version of this rag.