Foam-nest treefrogs choosing the waterfront

The foam-nest frog or foam-nest treefrog, scientifically known as Chiromantis xerampelina, is an arboreal or tree-living frog with discs on the toes and feet adapted for climbing. Their outer two fingers are widely spaced from and nearly at a right angle to their inner two fingers on each hand. The frog reaches 9 cm in length.

The skin of a foam-nest treefrog is slightly bumpy and dry, coloured white and brown but changing colour in response to temperature. Whiter when hot for reflecting unwanted heat, it is also white when dead, although probably cold if not lying in the sun. These frogs do not often swim or necessarily live near water. They are also found in arid areas, any place frequented by insects, their food.

Procreation starts with a female releasing eggs onto a branch or the ground as in the photo. All males in the vicinity with sperm available join in by clustering around her and fertilising the eggs as they appear. They do this by releasing sperm which they whip into a foamy “nest” using hind leg movement.

The female will leave temporarily to rehydrate before returning to the nest and please the males. This bizarre event may last for several hours. Offspring of these polyandrous encounters are said to be more likely to survive than from eggs fertilised by a single male.

The species distribution is in southern and central Africa; in South Africa only in northern KwaZulu-Natal and north of the Vaal River.

The habitat is diverse, including subtropical or tropical dry forest, savanna, shrubland, grassland, intermittent freshwater marshes, arable land, pastureland, rural gardens, urban areas, heavily degraded former forests, ponds, canals and ditches; look under your bed.

The Chiromantis genus comprises 18 frog species found in Africa and Asia. The species described here is not considered to be threatened in its habitat early in the twenty first century (Wikipedia; www.iucnredlist.org).