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The African clawed frog or platanna, Xenopus laevis, was first widely used in laboratories in pregnancy assays in the first half of the 20th century.When human chorionic gonadotropin, a hormone found in substantial quantities in the urine of pregnant women, is injected into a female X. laevis, it induces them to lay eggs.
A fully distended vocal sac in an Australian red-eyed tree frog (Litoria chloris) Italian tree frog (Hyla intermedia) with an inflated vocal sac. The vocal sac is the flexible membrane of skin possessed by most male frogs and toads. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call.
Dissection of a frog. Pain is an aversive sensation and feeling associated with actual, or potential, tissue damage. [1] It is widely accepted by a broad spectrum of scientists and philosophers that non-human animals can perceive pain, including pain in amphibians.
Warty frog species tend to be called toads, but the distinction between frogs and toads is informal, not from taxonomy or evolutionary history. An adult frog has a stout body, protruding eyes, anteriorly-attached tongue, limbs folded underneath, and no tail (the tail of tailed frogs is an extension of the male cloaca
First, if necessary, the frog performs a single, orienting bodily rotation ending with the frog aimed towards the prey, followed by approaching leaps, if necessary. Once within striking distance, the bullfrog begins its feeding strike, which consists of a ballistic lunge (eyes closed as during all leaps) that ends with the mouth opening.
The frog is a V-shaped structure that extends forward across about two-thirds of the sole. Its thickness grows from the front to the back and, at the back, it merges with the heel periople . In its midline, it has a central groove ( sulcus ) that extends up between the bulbs.
The first frog egg extract was reported in 1983 by Lohka and Masui. [1] This pioneering work used eggs of the Northern leopard frog Rana pipiens to prepare an extract. Later, the same procedure was applied to eggs of Xenopus laevis, becoming popular for studying cell cycle progression and cell cycle-dependent cellular events. [2]