Amphibians
Black Rain Frog
Breviceps fuscus · also called black rain frog, Tsitsikamma rain frog, plain rain frog
The black rain frog is a small, round, dark burrowing frog from the mountains of South Africa’s southern Cape, and it looks permanently, magnificently furious. It cannot hop or swim, so when something threatens it, it simply puffs up into a hard, immovable ball.
Overview
Black rain frogs live on the southern slopes of the Cape Fold Mountains, in moist fynbos, forest edges, and montane grassland with soft soil. They are burrowers, digging backwards with their hind feet and spending most of their lives underground, emerging to feed on small insects during and after rain. They are almost spherical, 4–5 cm, and dark brown to near-black.
The grumpy ball
The scowl is just anatomy — a low head, a downturned mouth, small eyes under a heavy brow. The frog has no toxins and no speed, so when threatened it inflates with air into a taut, hard sphere that is too big for a snake to swallow and wedges tight in its burrow.
Glued together
The male is much smaller than the female and cannot keep hold in the usual frog grip, so the female secretes a glue that cements him to her back until she has laid her eggs.
No pond needed
Eggs are laid in an underground chamber, and the young develop entirely inside the egg, hatching as tiny froglets. There is no tadpole and no need for standing water.
Status
The black rain frog is Least Concern — restricted to a small area of the southern Cape but common within it, secure as long as its habitat stands.
Black Rain Frog: common questions
Why does the black rain frog look so angry?
The permanently furious expression is an accident of anatomy, not a mood. The black rain frog has a very round, inflated-looking body, a small head set low on it, a broad mouth with strongly downturned corners, and small eyes under a low brow — a combination that reads to human eyes as a deep scowl. It became an internet celebrity for exactly this reason, usually photographed puffed up and glaring. The frog is not especially aggressive; the puffed posture people find so funny is a defensive bluff, and the "grumpy" face is just how this burrowing lineage of frogs is shaped.
What does the black rain frog do when it is threatened?
It inflates. Lacking the toxic skin of a toad, the leaping escape of a tree frog, or any real speed, the black rain frog gulps air and swells its already round body into a tight, rigid balloon. If it is in its burrow, this wedges it in place so a predator cannot pull it out; in the open, it makes the frog too large for a small snake's jaws and presents a smooth, hard surface with nothing to grip. Some rain frogs also give a high-pitched squeak or chirp when handled, and press themselves down and hold still. The whole strategy is passive resistance rather than fighting or fleeing.
How do black rain frogs reproduce without water?
They have cut the pond out of the frog life cycle entirely. The male calls from a burrow, the much larger female is cemented to him by a sticky skin secretion so the mismatched pair stays together, and she lays a clutch of large, yolk-rich eggs in an underground chamber. The developing frogs use the yolk as their food supply and pass through the tadpole stage inside the egg capsule, emerging as fully formed miniature frogs. Some rain frog species' unfertilised eggs form a nutritive plug that keeps the nest moist. This "direct development" lets the frogs live in habitats with no permanent standing water, relying only on damp soil.
Is the black rain frog endangered?
No. It is listed as Least Concern. Its range is fairly small — the southern side of the Cape Fold Mountains in South Africa — but within that area it is common, and much of its habitat lies in mountainous terrain and protected fynbos that is not easily farmed or built on. The main potential threats are habitat loss from agriculture, commercial forestry plantations, and expanding development along the Garden Route, plus the general risk that a species with a restricted range faces from fire regime changes and climate shifts. It is not currently collected in significant numbers for the pet trade.