This isn't just a cane toad. It's a Queensland cane toad, which means that it's likely to be more well-endowed than toads in the states of Western Australia and New South Wales. Those toads, according to a recent study of the subject, tend to have testicles about 30% smaller than their neighbors.
That may be a good thing. ABC News explains that there may be an evolutionary advantage to smaller testicles:
Researchers have previously found these frontline toads are generally bigger, stronger, and able to travel greater distances.
But it seems that the superior physical prowess comes at a cost, and that cost is the size of their testicles.
"There seems to be a trade-off between having long legs and being very mobile, and potentially your testes size," Dr Friesen said.
These frontier toads in Western Australia and New South Wales have less competition for potential mates, so they can do perfectly well with smaller testicles:
But the other reason is that being amphibians, cane toads have external fertilisation and that introduces the potential for "sperm wars".
"We have seen cases of this where there are multiple males on top of a particular female," Dr Friesen said.
But sperm wars are less likely for the big toads that are good at travelling to new territory where there is less chance of competition to fertilise eggs.
"When you get out to the frontline, it might be harder to find a mating partner, so there's less likelihood for that sperm competition," Dr Friesen said.
In general, a species that has greater sexual promiscuity tends to have larger testicles, which is why evolutionary biologists find them so fascinating:
"A bush cricket has the largest testes on the planet for their body size, and their testicles are 14 per cent of their body mass, where ours are well below 1 per cent," he said.
"There's great variation, and that variation we correlate with mating systems or how promiscuous the sexes are and how much sex they have with other individuals."
-via Dave Barry
Image: Jon Connell/Flickr