African bullfrog

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African bullfrog
Pyxicephalus adspersus, Boston Aquarium.jpg

African bullfrog ( Pyxicephalus adspersus )

Systematics
Order : Frog (anura)
Subordination : Neobatrachia
Family : African bullfrogs (Pyxicephalidae)
Subfamily : Pyxicephalinae
Genre : Pyxicephalus
Type : African bullfrog
Scientific name
Pyxicephalus adspersus
Tschudi , 1838

The African bullfrog ( Pyxicephalus adspersus , outdated syn .: Rana adspersa ) is also called the speckled grave frog or African grave frog . It is a very large, massive frog that is native to southern and southeastern Africa. The species used to be part of the family of real frogs , but at the beginning of the 21st century this family was divided into several families and the African bullfrogs form a separate family under the scientific name Pyxicephalidae .

features

Pyxicephalus adspersus has a maximum head-trunk length of 24.5 cm and can then weigh 1.4 kg. Only the males reach such dimensions; the female specimens remain significantly smaller. The body looks very compact and has a short, broad head with a huge mouth. There are three large, pointed, tooth-like bone structures in the lower jaw. The front and rear legs are very muscular, with the rear extremities sitting in the skin of the trunk up to the knee joints. On the upper side, several folds of skin run lengthways, and the skin has a warty-grainy structure. The color on the top ranges from greenish to gray to brownish. Occasionally dark spots appear, especially in young animals, also a light vertical stripe on the middle of the back. The underside and armpits are whitish to yellow in color. The pupils of the eyes are aligned horizontally. Webbed toes are only hinted at. The frogs use hardened heel bumps on the soles of their feet that have been shaped into shovels to dig quickly into the ground.

Occurrence, way of life

The African bullfrog is common in parts of Angola , Botswana , Kenya , Malawi , Mozambique , Namibia , Zambia , Somalia , South Africa , Tanzania, and Zimbabwe . It occurs in savannah areas where pools form during the rainy season. This is what the species needs for the reproduction and development of the tadpoles . For most of the year Pyxicephalus adspersus lives terrestrially and digs burrows to protect itself from drought. He can also survive longer periods of time in this (dry sleep). African bullfrogs carnivorously feed on living things that can overwhelm them; these are sometimes hardly smaller than themselves. In addition to invertebrates, small snakes, rats and mice, other frogs also belong to the food spectrum - intraspecific cannibalism is common, even among juveniles. The animals can allegedly live to be 45 years old, but probably only in captivity.

Predators, defensive behavior

The predators mainly include pelicans and Nile monitors . But humans also catch and eat these frogs. In the event of interference or danger, they defend themselves energetically by jumping and biting the opponent. As they do so, they utter a scream that is reminiscent of the roar of cattle.

Reproductive behavior

The spawning season is triggered by heavy rainfall. The males immigrate en masse into shallow pools of water and utter loud, barking mating calls. Younger animals tend to stay in the peripheral areas, while large, dominant males occupy the center. They show very aggressive territorial behavior and try to drive away rivals. It can also lead to injuries and death. The females that appear swim and dive in a targeted manner in the middle to mate with the strongest males . The eggs are then released in a concentrated manner on a flat spot, with the spawning being inseminated above the water level. The eggs of most of the females in a spawning community are fertilized by the same, dominant male. This later also guards the hatching tadpoles that develop within a few weeks.

Danger

The entire population of the African bullfrog is currently classified by the IUCN as "LC" ( least concern = not endangered). In western industrialized countries the species is occasionally kept as a terrarium animal. These individuals come from offspring.

Individual evidence

  1. ↑ African grave frog (Pyxicephalus adspersus) .
  2. ^ Darrel R. Frost: Pyxicephalus adspersus Tschudi, 1838 , Amphibian Species of the World: an Online Reference. Version 6.0. Electronic Database accessible at American Museum of Natural History, New York 1998-2017, accessed February 5, 2018

literature

  • Günther Nietzke: The terrarium animals. Vol. 1. Ulmer, Stuttgart 1977, ISBN 3-8001-7003-5 .

Web links

Commons : African bullfrog ( Pyxicephalus adspersus )  - Collection of images, videos and audio files