Shovel-Nosed Frogs (Hemisotidae)
Small frogs with powerful forelimbs and a hard, sharp snout for burrowing
1–3 in (25–80 mm)
Number of genera, species
1 genus; 8 species
Evolution and systematics
No fossils of this family are known. There is some evidence suggesting that this family is related closely to the rain frogs in the genus Breviceps, family Microhylidae. Another point of view is that these similarities follow from a common burrowing way of life and may not reflect a true relationship. No subfamilies are recognized.
These heavily built frogs have particularly robust skeletons associated with their burrowing habits. The species have a globular body, with short, muscular limbs. The well-muscled limbs end in short fingers and toes. The snout is sharp and has a hardened tip for digging, and a groove runs transversely behind the eyes. The frogs are smooth-skinned, with very small eyes. A large, flattened tubercle on the inner heel assists them in pushing headfirst into the soil. Adults are as small as 1 in (25 mm) and range in size to the largest, the spotted snout-burrower, at 3 in (80 mm). The back and sides are generally brown or purple with yellow spots or blotches.
Shovel-nosed frogs are native to open and wooded savanna where soils are sandy. The larvae are found in deep temporary pools with muddy substrates, and they occur together with tadpoles of many other species, such as Xenopus and Kassina.
The frogs are active during the wet season, emerging from burrows after dark to feed. They are found in habitats that become very arid before the rains start. In the dry season they burrow deep into banks and the mud of hollows, where they estivate. Adults emerge after rain to feed on the surface, although they may tunnel like moles and catch underground prey, such as earthworms.
Feeding ecology and diet
Shovel-nosed frogs eat nocturnal termites. In captivity they readily eat earthworms. They can be found after rain, feeding on the surface. They hunt earthworms by digging tunnels just below the surface. The hardened, sharp snout enables these frogs to move rapidly through loose soil.
Breeding is initiated by the first rains of the season. The male calls from a concealed site under vegetation at the edge of pools, usually on wet mud. The calls are prolonged buzzes. The male clasps the female and is dragged into the burrow by the larger female, who digs. The male then fertilizes the eggs in the nest. Females mate with only one male. Females remain with the developing eggs, which are laid in a burrow or under a log or stone. About 150–200 eggs are laid in a compact mass, each egg 0.08–0.10 in (2–2.5 mm) in diameter within a capsule 0.12–0.16 in (3–4 mm) in size. Clutch sizes may be as small as 30–35. At the top of the clutch are numerous empty egg capsules, which help protect the clutch. The nest is situated a little back from the water. Continuing rains cause the ponds to fill, and the water rises to the level of the tadpoles and liberates them.
Most species are widespread, and all are common. In areas where lowlands are drained and converted to housing schemes, much of the frogs' habitat is lost. This is especially true of species that are found in prime tourist areas along the east coast of Mozambique and South Africa.
Significance to humans
List of SpeciesMarbled snout-burrower
Hemisus sudanensis Steindachner, 1863, sub-Saharan Africa.
other common names
English: Marbled shovel-nosed frog, mottled shovel-nosed frog, pig-nosed frog, mottled burrowing frog.
Large females reach 2.2 in (55 mm). The eyes are small, the forearms are massive, and the toes are slightly webbed. Coloration varies, with dark gray or brown marbling or spots on a paler brown background. A light vertebral line is often present.
Found in most of sub-Saharan Africa, excluding rainforests, from Senegal to Eritrea, western Ethiopia, and Somalia and south into southern Kenya and the northern and northeastern parts of South Africa.
The frogs feed on the surface or hunt prey underground by digging tunnels.
feeding ecology and diet
These frogs eat a range of small insects and feast on winged termites when they emerge. They also readily eat earthworms.
Females are attracted to calling males. The male clasps the female, and she digs headfirst into the soft mud near a temporary pool. The eggs are laid and fertilized in an underground burrow. The female may remain near the eggs, which develop into tadpoles in the nest. Rain causes the pool to fill, and the tadpoles swim out of the nest as it floods. In extreme cases the tadpoles swarm onto the back of the female, who carries them to water.
significance to humans
Hemisus guttatus Rapp, 1842, northeastern South Africa.
other common names
English: Spotted shovel-nosed frog, spotted burrowing frog, eastern sharp-snouted frog.
The female may reach 3 in (80 mm); this is the largest species of snout-burrower. The toes are not webbed, and the back pattern is quite distinct, with a number of yellow dots on a dark purple or brown background. The head is pointed and small, with very small eyes. The snout tip is hard and used for burrowing. The arms are muscular, and the fingers are thick and strong.
Recorded from the KwaZulu Natal lowlands between Hluhluwe and Durban through the interior of South Africa.
Areas of flat, sandy soil that flood during the rains.
Active after dark, when they feed and breed.
feeding ecology and diet
Eats burrowing prey, such as earthworms, also takes insects that are active on the surface at night.
The advertisement call is a long, high-pitched buzz. Eggs are laid in chambers that are 5.9 in (15 cm) below the surface. Each clutch consists of some 200 eggs. Each egg is 0.10 in (2.5 mm) in diameter within a 0.16-in (4-mm) jelly capsule. The eggs are protected by a few top layers of empty jelly capsules.
The species is not directly threatened, although parts of the coastal habitat are threatened by development.
significance to humans
Channing, A. Amphibians of Central and Southern Africa. Ithaca, NY: Cornell University Press, 2001.
Kaminsky, S. K., K. E. Linsenmair, and T. U. Grafe. "Reproductive Timing, Nest Construction and Tadpole Guidance in the African Pig-nosed Frog, Hemisus marmoratus." Journal of Herpetology 33 (1999): 118–123.
Alan Channing, PhD
"Shovel-Nosed Frogs (Hemisotidae)." Grzimek's Animal Life Encyclopedia. . Encyclopedia.com. (August 19, 2019). https://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/shovel-nosed-frogs-hemisotidae
"Shovel-Nosed Frogs (Hemisotidae)." Grzimek's Animal Life Encyclopedia. . Retrieved August 19, 2019 from Encyclopedia.com: https://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/shovel-nosed-frogs-hemisotidae
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