Echidnas Have Four-Tipped Penises, And Scientists Want to Understand Why



As if Australia’s great menagerie of unusual beasties wasn’t already distinctive sufficient – with biofluorescing mammals that lay eggs and sweat milk – the pleasant weirdness extends even to their nether areas. Take an echidna’s junk, as an illustration.


I imply, simply take a look at that magnificent four-tipped monstrosity!

“They need to be fairly nicely endowed to get across the spines,” Currumbin Wildlife Sanctuary supervisor Sarah Eccleston instructed the ABC again in 2016.

“Every of the rosettes (heads) don’t all produce sperm directly; they use two of the heads at a time to ejaculate sperm.”

An echidna's penis. (Jane Fenelon)An echidna’s penis. (Jane Fenelon)

Previous analysis prompt echidnas alternate which of the quartet of penis ends they use every time – odd habits for a mammal.

“We discovered internally they act like they’ve two penises merged collectively and may use them independently,” College of Melbourne developmental biologist Jane Fenelon instructed ScienceAlert.

Learning injured short-beaked echidnas (Tachyglossus aculeatus) that sadly did not make it on the Currumbin Wildlife Sanctuary hospital, in addition to some tame sanctuary residents, Fenelon and colleagues discovered that blood stream may be directed in direction of one facet of their penis or the opposite. This might be how they management which half turns into erect. 

Why the animals solely use two ends of their penis at a time remains to be unclear, however the researchers suspect it happened by way of male competitors for females.


“By alternating the usage of both sides our tame echidna can ejaculate 10 instances with out vital pause, probably permitting him to out-mate much less environment friendly males,” they wrote in an announcement.

As if the animal was attempting to be as stubbornly distinctive as attainable, as soon as ejaculated, bundles of as much as 100 echidna sperms work collectively to attempt to attain an egg and grow to be an lovable little puggle.

“In most different species, sperm swim individually and it is each sperm for themselves,” the crew mentioned.

Marsupials like koalas even have multi-pronged penises – however theirs are solely forked in two. That is thought to turn out to be useful when attempting to get their sperm into the feminine’s twin uteruses

However such a objective does not appear to clarify the echidna’s weird penis. With regards to accessing the feminine’s uterus, echidnas are extra just like birds and reptiles than different mammals.


“All echidnas have a cloaca which is the one gap by way of which urine, poo and egg-laying happens. They’ve separate tubes for all of those however they merge near the exit,” defined Fenelon.


“We expect the echidna penis is lengthy sufficient to succeed in the place the uterus branches off although.”

The researchers have truly discovered one precedent for the echidna’s strange-shaped penis elsewhere within the animal kingdom.

“The one different animals I might discover that is just like this are some species of turtles,” mentioned Fenelon.

“There’s some proof that the penis in all amniotes (birds, reptiles and mammals) has the identical evolutionary origin and the monotremes are a lacking a part of that puzzle.”

This is smart on condition that echidnas and the one different monotremes that also survive at present (platypus) share an odd mixture of mammalian, fowl, and reptilian genetics. Monotremes parted methods with the remainder of us mammals 187 million years in the past. 

“We do know that they solely use their penis for mating, not urine,” Fenelon instructed Australian Geographic. “As a result of they do not want it for urine, they’d the liberty to make it way more elaborate and that is one thing you see in different species that solely use it for mating.”

Echidnas store their penises internally when not in use. (Jane Fenelon)Echidnas retailer their penises internally when not in use. (Jane Fenelon)

More often than not, male echidnas maintain their flamboyant bulge tucked neatly away inside their our bodies. This enables their reproductive appendage to remain secure and clear whereas they’re busy shoveling large quantities of filth with blade-clawed paws, foraging for ants and termites. 

Like too a lot of Australia’s wildlife, these distinctive animals are underneath risk largely from habitat destruction, which is regarding given the large ecosystem service they supply with their soil mixing habits – bettering soil well being, selling plant progress, and trapping carbon.

Fortunately, for now Australia’s echidnas are nonetheless widespread; however Papua New Guinea’s three long-beaked echidna species are endangered, so additional insights into their reproductive system might assist with their conservation.

This analysis was printed in Sexual Improvement.



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