Kangaroos – The 100 Days Project: Day 41 [60]

 Roölogy 102

Private Parts

Please excuse my appalling diagram. A draughtsman I am not. But it’s a way around copyright restrictions, and an easy way into Roölogy 102.

Sometimes, when you come across things like ‘Ten Surprising Facts About Kangaroos’, you’ll find one telling you that female kangaroos have three vaginas. Perhaps there’ll be another about kangaroos having long, thin, pointy penises, or about their penises coming out from behind or below, rather than above or in front of their scrotum. There might even be something about kangaroos having fork-tipped penises (they don’t: some other marsupials do, but not kangaroos). It’s time we got it out of the way (the subject, not the scrotum), not only because these things are amongst the very interesting parts of kangaroo anatomy, but because the penis will figure rather significantly in a later post, and the ‘three vaginas’ story has led to a bit of misunderstanding and contributed, via the notion/myth that all kangaroos, in good seasons, will have three joeys on the go at any one time, to exaggerations of their fecundity, and so to their exploitation.

I’m not sure I’d actually call them vaginas, if it were up to me, so much as two separate, lateral passages leading up, from the vagina, carrying sperm to one or another of the two (yes, two) uteruses, and a middle passage serving as the birth canal. This system/configuration (three canals, two uteruses) is not exclusive to kangaroos, but appears, with some variation, in marsupials more generally: i.e. it is a marsupial feature, not a feature of macropods alone. But of course (and thankfully) it’s not up to me.

As to the abovementioned myth, of the three joeys on the go at any one time. It’s true enough that many a kangaroo doe will have – and be nipple-feeding, on different formulae – an in-pouch joey and an out-of-pouch joey at the one time, but, as explained in an earlier post, the embryonic diapause that will enable her to have a further embryo waiting, in suspended animation, for an hormonal signal that one of these feeding regimes has ceased, is a Red kangaroo, Antilopean kangaroo, Wallaroo/Euro feature only, occurring only rarely in Eastern Grey kangaroos and never in Western Greys. 

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