The American bullfrog ( Lithobates catesbeianus or Rana catesbeiana ), often known only as bullfrog in Canada and United States, is an amphibian frog, a member of the Ranidae family, or a "true frog". This frog has a green olive back and sides of brownish spots with brownish and whitish streaks in yellow or gray. The upper lip is often bright green and the male has a yellow neck. It inhabits a large and permanent water body, such as swamps, ponds, and lakes, where it is usually found along the water's edge. Bullfrog males defend the territory during the breeding season. His call was reminiscent of the roar of a bull, which gave the frog its common name. These frogs come from the southern and eastern parts of the United States and Canada, but have been widely introduced in other parts of North America, Central and South, Western Europe, and parts of Asia, and in some areas are considered invasive species..
Bullfrog is harvested for use as a food in North America and in some countries where it has been introduced. It is also cultivated in a controlled environment, although this is a difficult job and is not always successful. Some international trade in frog legs occurs for human consumption. Bullfrog is used in biology classes at school for dissection and is sometimes kept as a pet.
Video American bullfrog
Taxonomy
Some scholars use the scientific name, Lithobates catesbeiana , though others prefer Rana catesbeiana . The systematic review of Holaractic's true frog in 2016 uses Rana catesbeiana , as does AmphibiaWeb, an online summary of the name and amphibious information available at http://amphibiaweb.org/.
Maps American bullfrog
Etymology
The special name, catesbeiana (feminine) or catesbeianus (masculine), is to honor the English naturalist Mark Catesby.
Description
The upper (dorsal) surface of the cow frog has an olive-green basalt color, either plain or with grayish-brown spots and lines. The ventral surface (below) is white with faded yellow or gray. Often, a clear contrast in color is seen between the upper lip of the green and the pale lower lip. The teeth are small and useful only in grasping. The eyes stand out with brown slices and horizontally almond-shaped pupils. Tympani (eardrum) is easily seen just behind the eyes and dorsolateral folds of skin tips close to them. Limbs branched or clad in gray. The front legs are short and sturdy and the hind legs are long. The toes are not webbed, but the rear toes have webbing between the numbers with the exception of the fourth, unattached toe.
Bullfrog is sexually dimorphic, with males smaller than females and has a yellow neck. Males have larger tympani than their eyes, whereas tympani in females have almost the same size as the eyes. Bullfrog measures about 3.6 to 6 in (9 to 15 cm) from muzzle to vent. They grow rapidly in the first eight months of life, typically gaining weight from 5 to 175 g (0.18 to 6.17 oz), and large adult individuals can weigh up to 500 g (1.1 lb). In some cases, the bullfrog has been recorded as reaching 800 g (1.8 Â £ lb) and measuring up to 8 in (20 cm) in length.
Distribution
Frogs are native to eastern North America. Its natural range extends from the Atlantic Coast to the west as far as Oklahoma and Kansas. It is not found on the offshore islands near Cape Cod and is largely absent from Florida, Colorado, Nebraska, South Dakota, and Minnesota. It has been introduced to the islands of Nantucket, Arizona, Utah, other parts of Colorado and Nebraska, Nevada, California, Oregon, Washington, and Hawaii. In these countries, the species is considered an invasive species and there is concern that this species may exceed the native species of amphibians and disrupt the ecological balance. This is very common in California, where it is believed to pose a threat to California's red-legged frog, and is considered a factor in the decline of these vulnerable species.
Other countries where frogs have been introduced include Mexico, western parts of Canada, Cuba, Jamaica, Italy, the Netherlands and France. It is also found in Argentina, Brazil, Uruguay, Venezuela, Colombia, China, South Korea and Japan. The reasons for introducing frogs to these countries include deliberate disengagement, either to provide food sources or as biological control agents, frog flees from breeding grounds, and fugitives or frog releases kept as pets. Conservationists are concerned that frogs are relatively immune to chytridiomycosis fungal infections and when it invades new territory, it can help spread the deadly disease to more vulnerable native frog species.
Breeding behavior
The bullfrog mating season usually lasts two to three months. A study of frogs in Michigan shows the males arrive at breeding grounds in late May or early June, and remain in the area until July. The territorial men who occupy the site are usually about 3 to 6 m (9.8 to 19.7 feet) and call out loud. There are at least three different types of calls have been recorded in male frogs in different situations. These special calls include territorial calls that are made as a threat to other men, advertising calls are made to attract women, and find a call that precedes the battle.
Frogs have a long mating season, with males continuing to engage in sexual activity. Men present in the nursery pool for longer periods than females during the entire season, increasing their chances of some marriage. Gender ratios are usually leaning towards men. Instead, women have a brief period of sexual acceptance during the season. In one study, women's sexual activity usually lasts for one night and mating does not occur unless the females initiate physical contact. Men only hold women after they show their willingness to marry. This finding refutes previous claims that the male frog will hold the nearest female regardless of whether the female has approved.
This male and female behavior causes competition between men and men to be high in frog populations and sexual selection for women to be an intense process. Kentwood Wells postulates lex, territorial polygyny, and the harem is the most likely classification for frog mating systems. Leks will be a valid description because men gather to attract women, and women arrive to the site for the purpose of intercourse. In a 1980 study of frogs in New Jersey, marriage systems were classified as resource-defense polygyny. Men defend the territory within the group and show a typical form of physical defense.
Choruses
Bullfrog men are joined into groups called choruses. The male choir behavior is analogous to the formation of bird lions, mammals, and other vertebrates. Choruses are dynamic, shaping and staying in contact for a few days, pausing, and then reshaping in new areas with different groups of men. The male movement experimentally has been recorded to be dynamic. In the Michigan study, choruses are described as "attraction centers" where their larger numbers increase the overall male acoustic appearance. This is more attractive to women and also attractive to other sexually active men. Choruses in this study are dynamic, constantly shaping and breaking up. New choruses are formed in other areas of this site. Men move and are very mobile in choruses.
A review of various studies of frogs and other dams noted the male behavior in the group changed according to the population density of the lex. At higher population densities, lek is preferred because of the difficulty in defending individual territories among large male populations. This difference leads to differences in the way women choose their partners. As the male population density is low and men maintain clearer and clearer areas, women's choices are largely determined by the quality of the region. When male population density is higher, women rely on other cues to choose their partners. These cues include the position of the male in the choir and the differences in male display behavior among other determinants. Social dominance in choruses is shaped through challenges, threats, and other physical appearance. Older men tend to get more central locations while younger men are confined to the periphery.
Choral ownership is the number of nights when a man participates in a breeding choir. One study distinguished between dominant chorus and tenure ownership. Stronger dominant ownership is defined as the amount of time a man maintains a dominant status. Choir ownership is limited due to increased risk of predation, loss of opportunity for foraging, and higher energy consumption. Calling postulated becomes very expensive for common people. Energy is also spent through the aggressive movement and interaction of male frogs in the choir.
Aggressive Behavior
To build social dominance in choruses, frogs exhibit various forms of aggression, primarily through visual display. Posture is a key factor in building a social position and challenging challengers. Territorial men pump postures while non-territorial males remain in the water by simply showing their heads. For dominant men (teritorial), their high posture shows their yellow neck. When two dominant men meet each other, they are involved in a wrestling battle. Men have their laps clasped, each individual in an upright position rising above the surface of the water. The New Jersey study notes that men will approach each other in a few centimeters and then tilt their heads, displaying their brightly colored gular sacs. These sugars are carnivorous in bullfrogs, with dominant and fitter males displaying yellow gulars. The New Jersey study also reported low posture with only heads exposed on the water surface typical of subordinates, or noncritical men, and women. High posture is shown by territorial males, which float on the surface of the water with their lungs increased, displaying their yellow gular. Men optimize their reproductive fitness in various ways. Early arrival at breeding sites, prolonged breeding of continuous sexual activity throughout the seasons, possession of the region located in the center of the choir, and the successful movement of dynamically changed choruses are a common way for men to maintain dominant, or territorial status , in the choir. Older men have greater success in all these areas than younger men. Some men exhibit a more inferior role, termed by many researchers as the silent status of men. This stealth man adopts a submissive posture, sitting near the resident male and not trying to drive them away. The silent man does not try to intercept the woman but waits for the territory to be empty. This is also called alternative male or satellite strategies.
Growth and development
After selecting males, females keep their eggs in their territory. During the mating rod, or amplexus, the male is above the female, holding it directly behind the front limbs. Women choose locations in shallow waters between vegetation, and put batches up to 20,000 eggs, and men simultaneously release sperm, producing external fertilization. The eggs form a thin floating sheet that can cover an area of ​​0.5 to 1.0 m 2 (5.4 to 10.8 sqÃ, ft). Embryos develop best at water temperatures between 24 and 30 Â ° C (75 and 86 Â ° F) and hatch in three to five days. If the water temperature rises above 32 Ã, Â ° C (90Ã, Â ° F), developmental abnormalities occur, and if it drops below 15Ã, Â ° C (59Ã, Â ° F), normal development stops. Newly hatched tadpoles indicate a preference for living in shallow water at the base of fine pebbles. This may reflect fewer number of predators in these locations. As they grow, they tend to move into deeper water. Tadpoles initially have three external gill pairs and several rows of labial teeth. They pump water through their gills with the movement of their mouth floor, trapping bacteria, single celled algae, protozoa, pollen, and other small particles in the mucus in the filtration organs in their pharanges. As they grow, they begin to swallow larger particles and use their teeth to chew. They have a downward-facing mouth, a deep body, and a tail with broad dorsal fins and abdomen.
The time for metamorphosis ranges from a few months in the southern part of the range up to 3 years in the north, where the cooler water slows the development. Maximum age in the wild is estimated 8 to 10 years, but one frog lives for nearly 16 years in captivity.
Giving Feeding
Bullfrogs are greedy, opportunistic, and ambush predators that prey on any small animal they can master and cram their necks. Bullfrog's stomach has been found to contain rodents, small reptiles, amphibians, crayfish, birds and bats, as well as many invertebrates, such as insects, which are common fodder from rancid frogs. These studies reveal a bullfrog diet to be unique among North Americans with the inclusion of large percentages of aquatic animals, such as fish, tadpoles, horn wolves, and dytiscid beetles. Bullfrog can capture large and powerful prey because of the powerful grip of their jaws after the first tongue attack. Bullfrog is able to create allowance for light refraction in the air-air interface by striking it in the posterior position to the target's perceived location. The comparative ability of frog toads to capture submerged prey, compared with green frogs, leopard frogs, and wooden frogs ( L. clamitans, L. pipiens , and L. sylvaticus , respectively ) was also shown in laboratory experiments.
Gesture of movement raises eating behavior. First, if necessary, the frog does a single rotation, the body-oriented ends with a frog aimed at the prey, followed by an approaching leap, if necessary. Once within range, the frog begins feeding, which consists of a ballistic attack (closed eyes as in all jumps) ending with mouth opening. At this stage, the slimy, slimy tongue extends toward its prey, often swallowing it, while the jaw continues its journey forward to close (bite) just as the tongue is pulled. The large prey that does not entirely enter the mouth is filled with hands. In laboratory observations, frogs take rats that usually swim underwater with prey in the mouth, apparently with favorable results transforming the mice's defenses from counter-attacks to fight for air. Asphyxia is the most likely cause of death of bloody prey.
Biomechanical background of tongue projection
The projection of the ballistic tongue of the associated leopard frog is possible because of the elastic structure that allows storage and release of the next elastic recoil energy. This account is for projected tongues with higher output power than those developed by muscle action alone. Also, the mechanisms reduce the tongue muscles from physiological constraints such as peak power output is limited - mechanical efficiency and thermal dependence by releasing activation of the mandibular depressor contractile unit from actual muscle movement. In other words, kinematic parameters developed by the contribution of elastic structures are different from those developed by muscle projections, accounting for differences in speed, power output, and thermal dependence.
Jumping -" catch mechanism "
Definition
Bullfrog is able to jump a distance of 10 times their body length because of the ability to activate muscle contractile units before plantaris muscle expansion. In this process, sarcoma contractions produce strains in elastic structures such as tendons, which in turn "capture" the energy produced by the strain. These are then released because the active plantaris stretches during the jump, adding to the energy generated by muscle action alone, resulting in a supramaximal force that allows the frog to jump a great distance. Thus, the capture mechanism relies on an elastic structure that acts as a muscle strengthener and its ability to absorb elastic strain energy and retain it for release and then explosive during jumping.
Benefits
The fact that the capture mechanism depends on the elastic structure used as a power amplifier shows a much more convenient set of conditions for frogs. The recording of sonomemometry and electromyography of the plantaris muscles reinforces the relationship between the presence of the muscle-tendon unit and the decrease, the gearing variable. By providing additional work output through the elastic strain energy coupling, elastic structures lighten the muscle from the shortening requirements at a velocity that would otherwise inhibit the amount of power produced, resulting in the magnitude of the power output. This is also aided by the decrease in gearing, which allows the bullfrog to produce the desired speed of movement by reducing the plantaris from a heavy shortening speed, achieving the desired speed by a slower and stronger contraction. As in the case of the projection of the ballistic tongue, the elastic structure in the plantaris muscle also gives it thermal independence. Jump peak power output and mechanical efficiency of high elevation frogs of the genera Hyla , Eleutherodactylus , Colostethus , and Atelopus Bufo at 35 ° C, Â ° C.
Ecology
Bullfrog is an important item of prey for many birds (especially large heron), North American river otters (Lontra canadensis ), predatory fish, and sometimes other amphibians. Predators from American bullfrogs once in the adult stage can range from 150 g (5.3 oz) kingfishers belted ( Megaceryle alcyon ) to 1,100 pounds of alligator America ( Alligator mississippiensis ). Eggs and larvae are uncomfortable for many salamanders and fish, but the high levels of tadpoles activity can make them more visible to predators unhindered by their discomfort. Humans hunt bullfogs as a game and consume their feet. The adult frogs try to escape by splashing and jumping into the deep water. A trapped individual may grumble or radiate a piercing scream, which may surprise the attacker enough to have the frog escape. Attack on a frog is likely to warn others around it of danger and they will all retreat into deeper water security. Bullfrog may be at least partially resistant to copperhead toxins ( Agkistrodon contortrix ) and cottonmouth snake ( Agkistrodon piscivorus ), although this species is known to be a natural predator of frogs as well as in the north. water snake ( Nerodia sipedon ).
Human use
American Frogs provide a source of food, especially in the South and some parts of the United States of the Middle West. The traditional way of hunting them is by rowing or swaying silently by boat or boat in a pool or swamp at night; when the frog calls are heard, the light shines on the frog that temporarily blocks its movement. Frogs will not jump into deeper water as long as it is approached slowly and steadily. When close enough, the frog was stabbed with multiple spears and taken to the boat. Bullfrog can also be stalked on land, with one more caution so as not to surprise them. In some states, breaking the skin while capturing them is illegal, and either grasping gigs or hand captures are used. The only part that is usually eaten is the hind legs, which resemble small chicken drumsticks and can be cooked in the same way.
Commercial bullfrog culture in closed pools near nature has been tried, but filled with difficulties. Although pellet feed is available, frogs do not want to eat artificial food, and provide a fairly challenging live prey. Illness also tends to be a problem even when great attention is taken to provide sanitary conditions. Other challenges to be overcome may be low predation, cannibalism, and water quality. The frogs are big, have a strong leap, and inevitably run away after that they can wreak havoc among the native frog populations. Countries that export bullfrog foot include the Netherlands, Belgium, Mexico, Bangladesh, Japan, China, Taiwan, and Indonesia. Most of these frogs are caught from the wild, but some are preserved. The United States is a frog foot importer.
American bullfrog is used as a specimen for dissection in many schools around the world. These are the amphibians of the states of Missouri, Ohio, and Oklahoma.
References
External links
- Herps of Texas: Rana catesbeiana
- The British Columbia Frog Watch Program: Fact Sheet of the Buffalo Frog
- Bullfrog at allaboutfrogs.com
- Bullfrog in the Global Specific Species Database
- Bullfrog recordings
Source of the article : Wikipedia
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