Bullfrog
| American Bullfrog | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 |
|||||||||||||||
| adult male | |||||||||||||||
| Conservation status | |||||||||||||||
| Biological classification | |||||||||||||||
|
|||||||||||||||
| Binomial name | |||||||||||||||
| Rana catesbeiana (Shaw, 1802) |
|||||||||||||||
 Bullfrog range
|
|||||||||||||||
The American Bullfrog (Rana catesbeiana[2][3] or Lithobates catesbeianus)[1][4][5] is an aquatic frog.[6] It belongs to the family Ranidae, or 'true frogs'.
Bullfrogs are native to most of North America. The ones that live in northern America hibernate during winter. However, bullfrogs in southern US states are active all the time. There has been sightings of bullfrogs in other countries. These include, Eastern Europe, China, Australia, South Korea, Cuba, and South America. These bullfrogs were imported on ships.
Bullfrogs, which eat almost anything that fits in their mouths, live in large, permanent bodies of water: swamps, lakes, and ponds. They like to stay near the edge of the water. During a rain storm, they may travel on land, and numbers may be seen on roads. They travel in search of a new habitat. Bullfrogs can live up to eight years. They may live longer if they are in captivity in warm weather.[7]
Bullfrogs can be kept as pets. Captive bullfrogs are given rodents, small fish, crickets, worms, and fruit flies as food and treats. Pet owners may add supplements on the frogs food for health. Bullfrogs can decrease the mosquito population. They do this by eating most of the mosquito's larvae. They do not move during the day, except if there is food nearby or when threatened. Bullfrog legs are a favorite food for the Chinese and in Southern and Midwestern United States. The IUCN rates the bullfrog as "Least Concern", which means that they are not an endangered species. However, their population is dying because of habitat loss, water pollution, pesticides and over harvesting.
Contents |
[change] Taxonomy
The American bullfrog (Rana catesbeiana) is one of 90 species of the genus Rana.[8][9] The parent family for Rana is Ranidae, or "true frogs".[10] Ranidae is split into nine sub families. Ceratobatrachinae (southeast Asia), Conrauinae (Africa), Dicroglossinae, Micrixalinae (India), Nyctibatrachinae (India), Petropedetinae (Africa), Ptychadeninae (Africa), Raninae (Australia, South America), and Ranixalinae (India).[10] The American bullfrog's genus name comes from the Latin word rana, which means frog. Catesbeiana came from Mark Catesby, an English naturalist, who first discovered the bullfrog.[11]
[change] Adults
The American bullfrog is the largest of the "true frogs" family.[12][13] They can weigh almost a pound (227 g).[9] Females can reach up to 8 inches (20 cm) when they are adults.[14] Males can reach up to 6 inches (16cm).[15] Bullfrogs are either brown or green. They can also have darker spots on their back.[13][16] Bullfrogs have webbed feet for swimming.[12][17] They can leap up to 6 feet. Male bullfrogs are much bigger and can be heard roaring when mating with a female. Males also have bigger tympanic membranes which cover their ears.[13] Bullfrogs have brown or gold eyes. They also have broad, flat heads and bodies.[12][13] Females are longer than males.[16] The mouth of a bullfrog are small and have tiny teeth inside.[17] Bullfrogs have toxic skin, though not harmful to humans. The toxins make it less likely that other animals will eat them.[15][18]
[change] Habitat and distribution
Bullfrogs are semi-aquatic frogs. They are known to be near lakes, swamps, rivers, and ponds. They spend most of their time swimming. Bullfrogs can be found in North and South America, Canada, Australia, Brazil, South Korea, Colombia, Cuba, Eastern Europe, and China.[14][15][19] Bullfrogs are native to North America. They were imported by ships to other parts of the world.[19] Bullfrogs in northern United States hibernate during the winter time. They hibernate in mud at the bottom of ponds and rivers.[19] They can breathe under water as long as they can get oxygen through their skin. While hibernating, bullfrogs can slow their heart rate and metabolism down.[19] Bullfrogs are more active at night. During the day, bullfrogs may rest under vegetation.[20]
[change] Feeding
Stomach content studies going back to 1913 suggest that the bullfrog preys on any animal it can overpower and stuff down its throat.[14][15] Bullfrog stomachs have been found to contain rodents, baby muskrats, small turtles, snakes, frogs (including bullfrogs), birds, and a bat, as well as the many invertebrates, such as insects.[14][21][22] These studies show the bullfrog's diet is unique among North American Rana.[21]
In captivity, pet frogs will be given crickets, worms, small fish, rodents and fruit flies.[22]
[change] Reproduction
Adult female bullfrogs can grow up to 8 inches (20 cm) and weigh up to ½ a pound (227 g). Male bullfrogs can be as tall as 6 inches (16 cm). Males have bigger tympanic membranes which covers their ears. Males also have a yellow-ish color mottle. When mating, a male bullfrog grabs the female and begins roaring. The female lays her eggs in shallow waters. The male releases sperm on the eggs as fertilizer. A female can lay up to 20,000 eggs. The eggs hatches after four days. They are called "tadpoles" and live in the water eating algae. They become frogs in more than a year. In captivity, they can become frogs in twelve weeks. There are many predators such as larger fish, crustaceans, and some birds that eat most of the eggs and tadpoles. When they become adult frogs, the predators become food for the bullfrogs. Bullfrogs have toxic skin to scare away their prey, but it is not harmful to humans.
[change] Development of tadpoles
Once the tadpoles become "froglets", they begin hopping out of the water and into land.[23] They loose their tails once they are at this stage.[24] The froglets will stop using their gills and use them as lungs.[25] They begin eating small insects. The froglets will remain near the water where they were laid. If there is a drought, they will search for a new habitat.[26] At the time, froglets become easy prey to larger frogs, reptiles, raccoons, foxes, and birds.[27]
Froglets become adult bullfrogs after four months they began hopping on land. Adult bullfrogs begin eating larger prey such as smaller frogs, snakes, birds, fish, insects, and rodents.[28] Adults can help decease the mosquito population by eating most of their larvae.[29] Males become territorial.[30] This means that they will battle with other males if they get close to their habitat.[31] The males battle so they can mate with other females. If there is a drought, bullfrogs will leave their habitat.[32] During a rain storm, they move quicker. They are seen in large groups.[33]
[change] Behavior
Bullfrogs in southern US states are active all the time. Bullfrogs in northern US states hibernate during the winter time.[34] Mating season begins in spring and ends in early summer.[35] In northern US states, bullfrogs will begin coming out of hibernation.[36] They will begin eating and swimming. During the summer, bullfrogs will spend most of their time in the water. They will feed on mosquito larvae. During the fall, northern US states bullfrogs will begin hibernating. Southern US states bullfrogs will become semi-aquatic. During the winter time, they will continue to be semi-aquatic. If the weather outside is cold, they will hibernate for a few days. Bullfrogs are active at night.[37] They can be seen hopping around gardens and streets. During the day, they will be near the edge of the water. During the daytime, they become motionless (not moving). They will begin moving if prey is nearby or if they feel threatened.
[change] Conservation status
The IUCN rates the bullfrog as "Least Concern".[1] This is because they are found almost in every continent.[38] "Least Concern" means that the bullfrog is not an endangered species. There are more bullfrogs in southern United States than there is in the north. However, bullfrogs populations are decreasing because of habitat loss, water pollution, pesticide and over harvesting.[39] Bullfrogs have been blamed for the extinctions of the California Red-legged Frog. They have also been blamed for many other amphibian extinctions in California.[40]
[change] Human use
Bullfrogs are a source of food for Southern United States and the Midwestern United States.[41] People hunt bullfrogs at night near rivers. The bullfrogs' legs are cooked, while their backs are fried.[42] In China, bullfrogs are sold alive for eating. However, they are later cooked dead with vegetables. In the state of California, people must have a license to catch bullfrogs for food.[40] In schools, bullfrogs are dissected in biology classes. Usually, this is done in grammar school.[43] The dissecting is a method for teaching students the anatomy of a bullfrog.[43] Bullfrogs are also kept as pets.[44] They are kept in aquariums or a terrarium.[41] A terrarium is a tank that is decorated with plants and soil on one side. On the other side, there is water.[41] A bullfrog would need one place for land and another for water.[41] Bullfrogs can live up to 8 years. They can live longer if they are in captivity in warm weather.[14]
[change] References
- ↑ 1.0 1.1 1.2 Lithobates catesbeianus, IUCN
- ↑ Hillis 2007, pp. 331-338.
- ↑ Wilcox 2005, pp. 299-314.
- ↑ "American Bullfrog (Lithobates catesbeianus)". Ontario Nature.
- ↑ "Lithobates catesbeianus". USDA. http://www.invasivespeciesinfo.gov/aquatics/bullfrog.shtml. Retrieved May 24, 2012.
- ↑ "bullfrog (amphibian) -- Britannica Online Encyclopedia". britannica.com. 2012 [last update]. http://www.britannica.com/EBchecked/topic/84456/bullfrog. Retrieved 29 May 2012.
- ↑ Casper G.S. and Hendricks R. 2005. Amphibian declines: the conservation status of United States species. University of California Press.
- ↑ Wilcox 2005, pp. 331-338.
- ↑ 9.0 9.1 Wechsler 2002, p. 5.
- ↑ 10.0 10.1 Pauly 2009, pp. 115-128.
- ↑ "Where did it come from?!". BioWeb.com. Natural blues. http://bioweb.uwlax.edu/bio203/2010/schams_kell/classification.htm. Retrieved May 27, 2012.
- ↑ 12.0 12.1 12.2 Hall, Madeleine. "The Characteristics of a Bullfrog". eHow. Demand Media. http://www.ehow.com/info_8224072_characteristics-bullfrog.html. Retrieved May 27, 2012.
- ↑ 13.0 13.1 13.2 13.3 "American Bull Frogs". Essortment. Demand Media. http://www.essortment.com/american-bull-frogs-23440.html. Retrieved May 27, 2012.
- ↑ 14.0 14.1 14.2 14.3 14.4 "American Bullfrog". National Geographic. National Geographic Society. http://animals.nationalgeographic.com/animals/amphibians/american-bullfrog/. Retrieved May 24, 2012.
- ↑ 15.0 15.1 15.2 15.3 Peabody, N.E.. "Bullfrog habitat". eHow. Demand Media. http://www.ehow.com/facts_5194695_bullfrog-habitat.html. Retrieved May 27, 2012.
- ↑ 16.0 16.1 Elizabeth, R. (November 29, 2010). "Species Spotlight: North American Bullfrog". BrightHub. BrightHub. http://www.brighthub.com/environment/science-environmental/articles/21309.aspx. Retrieved May 27, 2012.
- ↑ 17.0 17.1 Dickerson 2009, p. 235.
- ↑ Wechsler 2002, p. 7.
- ↑ 19.0 19.1 19.2 19.3 Papagiorgio, Nicole. "Bull Frogs Habitat". eHow. Demand Media. http://www.ehow.com/info_8578055_bull-frogs-habitat.html. Retrieved May 27, 2012.
- ↑ Scott, Daniel. "Bullfrog's Environment". eHow. Demand Media. http://www.ehow.com/info_8604727_environment-bullfrog.html. Retrieved May 27, 2012.
- ↑ 21.0 21.1 Cardini F. 1974. Specializations of the feeding response of the bullfrog, Rana catesbeiana, for the capture of prey submerged in water. M.S. Thesis, U. of Massachusetts, Amherst, MA
- ↑ 22.0 22.1 Bartlett 2007, p. 81.
- ↑ Lawrence 2012, p. 13.
- ↑ Purser 2006, p. 16.
- ↑ Lawrence 2012, p. 11.
- ↑ Purser 2006, p. 18.
- ↑ Lawrence 2012, p. 14.
- ↑ Purser 2006, p. 30.
- ↑ Purser 2006, p. 34.
- ↑ Murphy 1984, p. 14.
- ↑ Murphy 1984, p. 5.
- ↑ Purser 2006, p. 36.
- ↑ Purser 2006, p. 41.
- ↑ Gray 2009, p. 22.
- ↑ Gray 2009, p. 25.
- ↑ Gray 2009, p. 28.
- ↑ Gray 2009, p. 17.
- ↑ Gray 2009, p. 29.
- ↑ Lannoo 2005, p. 546.
- ↑ 40.0 40.1 Storer 2004, p. 256.
- ↑ 41.0 41.1 41.2 41.3 Danielson 2011, p. 70.
- ↑ Gray 2009, p. 9.
- ↑ 43.0 43.1 Glotzhaber 2007, p. 85.
- ↑ Gray 2009, p. 7.
[change] Books
- Davidson, Charles; Elliott, Lang; Gerhardt, Carl (2009), The Frog Book: North American Frogs and Toads, Houghton Mifflin Harcourt, pp. 344, ISBN 0618663991
- Wells, Kentwood (2007), Rosen Publishing Group, pp. 1400, ISBN 0226893340
- Murphy, Patricia (2003), A Frog's Life: Learning Sequential Order Using a Timeline, University Of Chicago Press, pp. 16, ISBN 0823989054
- Lannoo, Michael (2005), Amphibian Declines: The Conservation Status Of United States Species, University of California Press, pp. 1115, ISBN 0520235924
- Storer, Tracy; Usinger, Robert; Lukas, David (2005), Sierra Nevada Natural History, University of California Press, pp. 592, ISBN 0520240960
- Glotzhaber, Robert (2000), Biology Laboratory Set Student Manual, Hayden Mcneil Publisher, pp. 100, ISBN 0520240960
- Glotzhaber, Robert (1973), The Life Cycle of a Bullfrog, Children Press, pp. 31, ISBN 0871912333
- Wechsler, Dough (2002), Bullfrogs (Really Wild Life of Frogs), Powerkids Press, pp. 24, ISBN 0823958558
- Purser, Phillip (2006), Tadpole Care, TFH Publications, pp. 64, ISBN 0793810353
- Gray, Susan (2009), Bullfrog (Animal Invaders), Cherry Lake Publications, pp. 32, ISBN 1602793271
[change] Other websites
 |
Wikimedia Commons has media related to: Rana catesbeiana |
 |
Wikispecies has information on: Rana catesbeiana. |
