Exhibitionist echidna reveals bizarre penis

[ZenGum]

With a thread title like that, how could you not look?

The full story is at new scientist, but here are some highlights.

Echidnas (aka spiny anteaters) are notoriously shy and studying them was difficult. A few things were known though:

...the male ejaculates using only one half of its penis ....

The researchers have also observed that hundreds of sperm team up to form bundles that swim much faster than individual sperm in the spiny anteater’s semen

... up to 11 males may form a queue behind one female to copulate with her....

Like when Labrat goes running, from what I read.

However, scientists finally found an echinda less shy than most.

The creature had been ‘retired’ from a zoo as it produced an erection when being handled at public viewing sessions

"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.

And if you're still curious (or getting aroused) there's even a video, either on Youtube or with the original story.
The video is most notable for the proportionally large (to body size) four-headed monster, and the fact that the handler is not wearing gloves of any kind.