Australian Ground Frogs: Limnodynastidae

Physical characteristics: Sitting as it often does with its short legs tucked against its body, the northern spadefoot toad has a shape like a golf ball. Some people even call this species a golfball frog. A small head with large eyes and a very short snout barely pokes out of its body. Its head, back, legs, and throat are brown to greenish brown or gray with black markings and are covered with warts. The warts may be tipped in white. Its belly is white. This frog has long, pointed toes and tubercles on its feet, similar to those of the painted frog, which give it the spadefoot name. Females usually grow to 1.8 to 1.9 inches (4.5 to 4.9 centimeters) long from snout to rump. The males sometimes are a bit smaller, usually reaching 1.3 to 1.9 inches (3.4 to 4.8 centimeters) in length.

Geographic range: The northern spadefoot toad lives in northern Australia, including parts of Kimberley, Western Australia, and Queensland.

When threatened, the northern spadefoot toad's warts ooze a gluey goop. A predator that unwisely bites at one of these frogs gets a mouth full that quickly hardens, turns bright orange, and becomes difficult to clean off. (Illustration by John Megahan. Reproduced by permission.)

Habitat: The northern spadefoot toad spends much of its life underground, but comes to the surface after heavy rains. It breeds in marshes, swamps, and small pools of water.

Diet: With the flip of a tongue out of the small mouth, the northern spadefoot frog snatches up small insects and other invertebrates to eat. The tadpoles appear to eat by straining tiny organisms out of the water.

Behavior and reproduction: This species uses the spades on its feet to burrow into the soil. In rainy weather, the northern spadefoot toad digs out of its underground home to look for insects, and in the breeding season, to mate. With its short legs and pudgy-looking body, this frog walks rather than hops and is not able to outrun most predators. It does, however, have a way of defending itself. When threatened, its warts ooze a gluey goop. A predator that unwisely bites at one of these frogs gets a mouth full of goop that quickly hardens, turns bright orange, and becomes difficult to clean off.

In the rainy, breeding season, males move to marshes, swamps, and newly filled pools of water and call from shallow spots. Their call is a loud, repeated "whoop." When the male calls, his body fills with air like a balloon. If he feels threatened, he will let the air out and sink out of sight. Males mate with females by climbing onto their backs and hanging on in front of the females' hind legs. Each female lays 500 to 1,400 eggs on the water's surface, and the eggs later sink and tangle in underwater plants as they hatch into tadpoles. The tadpoles turn into froglets when they are about two months old. The young froglets look much like the adults, but are often speckled with bright yellow, red, and black spots.

Northern spadefoot toads and people: People rarely see this frog.

Conservation status: The World Conservation Union (IUCN) does not consider this common species to be at risk. Some of its populations live in protected areas. ∎