From Encyclopedia Jr, free information reference for Kids
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For other uses, see Bullfrog (disambiguation).
The American Bull Frog (Rana catesbeiana) is an aquatic frog, a member of the family Ranidae, or "true frogs", native to much of North America.
[edit] Physical description
This is a large species and can grow to a length of 6 inches (15 cm) with a weight of upto 1.5 lb (750 g). Females are typically larger than males. They are generally varying shades of green or brown, with dark brown, dark green, or black blotching and a yellow or white underside.
The skeleton of an adult frog consists of bone, hyaline cartilage, and calcified cartilage. The calcified cartilage can be found throughout the body of the frog, its particularly more noticeable in the epiphyses of the long bones in the limbs and shoulder-gridle, etc. The frog not only has a scapula, but a suprascapula which allows for greater range of motion for long jumps. In the frog the radius and ulna have become fused into a single bone, the radio-ulna, and the tibia and fibula have become fused into a single bone, the tibio-fibula.
A young female with a relatively small tympanic membrane
The vertebrae of the frog comprise ten bones; nine are true vertebrae, and the rod-shaped urostyle that is almost as long as the other nine. The head of the frog is flat but its form depends on the extensive separation of the jaw bones; the orbital cavities and the horizontal direction of their floor also have an effect on the form of the head. The central nervous system of the frog is made up of the spinal cord and the brain, where the spinal cord is a bit smaller than the brain. The peripheral nervous system contains the cranial nerves and spinal nerves.
[edit] Ecology and behaviour
Bullfrog in typical aquatic habitat.
The American Bull Frog uses its skin, Buccal Cavity, and lungs for respiration. Cutaneous ("skin") gas exchange is very important in all amphibians. They are aptly named, as their call is an extremely loud, guttural bellow that carries a long distance, giving the impression that the frog is much larger than it actually is.
[edit] Diet
This species is carnivorous and will consume almost anything that fits into their mouth which they can overpower, including insects, small , fish, snakes, and even other frogs.
[edit] Reproduction
The male reproductive organs are the testes and their duct, and the female have ovaries. In the spring the male calls the female from the water. The female lays up to 25,000 eggs, and these eggs will become tadpoles. Their metamorphosis brings them the organs that are only found in the adult frogs and takes between 12-24 months. There are three major changes that take place during the metamorphosis: 1) Premetamorphisis which is when the embryo genesis and growth and development occur, during this time the thyroid gland is absent. 2) Prometamorphisis is the period in which the concentration of the endogenous thyroid hormone rises 3) Metamorphosis is the period when the tadpole's tail shrinks back into the frog's body. Other organs too undergo changes such as the liver and the intestine and the gills will be gone as well. The adult frog can live up to 13 years.
[edit] Distribution
The American Bull Frog is native to North America. They are found in the United States, Canada and Mexico, east of the Rocky Mountains, but have been introduced to many other localities throughout the world. In Europe and the western U.S. measures are often taken to control its spread because it competes with, and often drives out, native species.
Bull Frog,
R. catesbeiana
[edit] Human use
While occasionally kept as pets, the American Bull Frog provides a minor food source, especially in the southern states of America, and in some areas of the Midwestern United States. In a few locations they are commercially cultured in ponds, but the traditional way of hunting them is to paddle or pole silently by canoe or flatboat in streams or swamps at night; when the frog call is heard, fix a strong light on the frog. The frog will not jump into deeper water as long as movement is slow and steady. When close enough, the frog is gigged and brought into the boat. The only parts eaten are the rear legs, which resemble small chicken drumsticks and, sometimes, the backs, and they are usually fried for consumption. The American Bull Frog is also used as a specimen for dissection in many schools across the world.
[edit] Space flight
Two Bullfrogs were launched into orbit in 1970 on the Orbiting Frog Otolith spacecraft.
[edit] Trivia
The American Bullfrog is the State Amphibian of Missouri and Oklahoma.
[edit] External links
[edit] References
- Santos-Barrera, G. et al. (2004). Rana catesbeiana. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006. Database entry includes a range map and justification for why this species is of least concern
