Frogs (Xenopus) in medical research
Frogs are especially useful in animal research because of the large number of eggs they can produce. These can number in the hundreds, or even thousands, each time they mate. Because the eggs grow externally, and are transparent, it is easy for scientists to watch the eggs grow and minitor the stages of early development. The African clawed frog, Xenopus laevis, has been particularly useful for studying very early events, such as the formation of the neural plate, which develops into the nervous system. This video has no sound.
Frogs are counted in the same group as fish, amphibians, reptiles and birds. Collectively, they account for 21 percent of animal research.