African clawed frog

The African clawed frog (Xenopus laevis, also known as platanna) is a species of South African aquatic frog of the genus Xenopus. It is up to 12 cm long with a flattened head and body but no tongue. Its name derives from its three short claws on each of its hind feet, which it probably uses to stir up mud to hide it from predators.

Although X. laevis is not blessed with the short generation time and genetic simplicity generally desired in genetic model organisms, it is an important model organism in developmental biology. X. laevis takes 1 to 2 years to reach sexual maturity and, like most of its genus, it is tetraploid. However, it does have a large and easily manipulable embryo. The ease of manipulation in amphibian embryos has given them an important place in both historical and modern developmental biology. A related species, Xenopus tropicalis, is now being promoted as a more viable model for genetics. Roger Wolcott Sperry used X. laevis for his famous experiments describing the development of the visual system. These experiments led to the formulation of the Chemoaffinity hypothesis.

Xenopus oocytes provide an important expression system for molecular biology. By injecting cDNA or cRNA into the developing oocyte, scientists can study the protein products in a controlled system. This allows rapid functional expression of manipulated cDNAs (or cRNA). This is particularly useful in electrophysiology, where the ease of recording from the oocyte makes expression of membrane channels attractive. One challenge of oocyte work is eliminating native proteins that might confound results, such as membrane channels native to the oocyte.

X. laevis is also notable as having been a standard method of pregnancy testing. Human chorionic gonadotropin is a hormone found in substantial quantities in the urine of pregnant women; when injected into the female X. laevis it induces them to lay eggs.


African clawed frogs as pets

An immature pigmented African Clawed Frog.In recent years African Clawed Frogs have become popular pets. It has been found that there is a strong connection between the international trade of X. laevis and a global decline in frog populations due to the spread of chytridiomycosis [1].

Often confused with the much smaller African Dwarf Frog, the clawed frog has webbing on its back feet but has four unwebbed fingers on each front foot. Females grow to an average of 5 inches (130 mm) snout to vent; males are generally smaller, around 3.5 to 4 inches (90 to 100 mm). They are social frogs and should be kept with others of their species. Highly carnivorous, they will attack and eat any fish kept with them. African Clawed Frogs should be kept in 10 US gallons of water per frog, and are completely aquatic. A well fitting lid is required for keeping clawed frogs, as they can leap out of most tank set-ups. As with fish-keeping, it is necessary to closely monitor water quality and change water weekly in order to keep these frogs healthy. If properly cared for, African Clawed Frogs can live over 15 years.

A common mis-labeling in pet shops is the "African Dwarf Clawed Frog". Dwarf Frogs and Clawed Frogs are two independent species.


African dwarf frogs of genus Hymenochirus, also known as dwarf aquatic frogs (ADF or DAF for short), are frogs native to Sub Saharan Africa. They are members of Family Pipidae.

They are entirely aquatic though they do break the water surface as they are air breathers. They are nearly blind at close range being far-sighted, but have keen sight 7 cm or further away. They rely on a sharp sense of smell and touch to find food. They are meat eaters and so eat small insects, worms, fish meat and red mosquito larvae also known as bloodworms (though this food should only be feed once a week in captivity).

They are usually only an inch and a half in body length when fully grown, females are larger than the males. They are cousins to the large African clawed frog but are much smaller. They are often sold in pet shops and can live in captivity for 10-20 years.

It is often the case that the African clawed frog is confused with this frog when very young. But it is easy to tell the two species apart. Look at the hands of the frog. If the fingers are webbed then it is an ADF.

The male makes a quiet mating call when sexually active. The female is silent most of the time.

You can sex the frog quite easily once it is over 6 months old. Behind each armpit, the male develops a gland spot which becomes red when sexually mature.