If you’ve been following this blog for a while, you may know that for the past six months, we’ve been posting Freaky Frog articles every fortnight. During our journey through the weird and wonderful world of these amazing amphibians, we’ve looked at the delightfully named ‘scrotum frog’, we’ve examined the remarkable defensive mechanism of the ‘wolverine frog’, and we’ve marvelled at the cryogenic wood frog. There have been frogs that brood their young in their vocal sacs. Toads that brood their young inside pockets in their own skin. Frogs with moustaches. Frogs that practise ‘reproductive necrophilia’.
From the 1930s through to the 1960s, a small aquatic frog was used as a biological pregnancy test. This may sound suspiciously like one of those medieval folk remedies – in the same vein of shaving the rear end of a live chicken and holding it under your armpit to cure the plague – but this frog really could tell if you were pregnant or not.
Amphibians rely on water for a number of very important reasons. Firstly, although most modern amphibians possess lungs, many of them are extremely simple and are not completely sufficient for their needs. This means that oxygen intake is often supplemented by absorption through their thin, permeable skin – and this can only happen if it is suitably wet.
Over the past couple of months, The Nature Nook has been looking at frogs that exhibit truly bizarre breeding behaviours. From the male that broods his offspring in his vocal sac to the toad whose tadpoles develop within pockets in the skin on their mother’s back, there seems to be no shortage of unusual ways in which anurans reproduce and take care of their young.
Seahorses are well-known for their unconventional approach to breeding. Famously, the males are the ones that become pregnant, carrying the fertilised eggs in a brood pouch on their bellies until the fully developed young are ready to be born. This level of paternal responsibility is extremely rare in the animal kingdom. In fact, other than seahorses and their close relatives, the only vertebrate species in which the male effectively becomes pregnant is a tiny amphibian from South America called Darwin’s frog.