<P> Bullfrogs are able to jump distances 10 times their body length due to the ability of activating muscular contractile units prior to extension of the plantaris muscle . In this process, sarcomeric contraction generates strain in elastic structures such as tendons, which in turn "catch" the energy generated by the strain . Such is subsequently released as the plantaris actively stretched during jumping, adding to the energy generated by muscular action alone, thus generating supramaximal powers that allow the bullfrog to jump great distances . Thus, the catch mechanism relies on elastic structures acting as muscle power amplifiers and their ability to absorb elastic strain energy and retain it for later explosive release during jumping . </P> <P> The fact that the catch mechanism relies on elastic structures used as power amplifiers implies a series of conditions much convenient for the bullfrog . Sonomicrometry and electromyographic recordings of the plantaris muscle corroborate a relationship between presence of muscle - tendon units and decreasing, variable gearing . By supplying additional work output through the coupling of elastic strain energy, elastic structures relieve the musculature from the need of shortening at velocities that would otherwise hinder the amount of force generated, thus the magnitude of power output . This is also aided by a decreasing gearing, which makes it possible for the bullfrog to generate the desired velocity of movement by relieving the plantaris from strenuous shortening velocities, achieving the velocity desired by slower, forceful contractions . As in the case of its ballistic tongue projection, elastic structures in the plantaris muscle also confer it thermal independence . Jumping peak power output and mechanical efficiency of high - elevation frogs of the genera Hyla, Eleutherodactylus, Colostethus, and Atelopus, which achieve these at temperatures as low as 5 ° C, are not statistically different from those achieved by tropical Bufo frogs at 35 ° C . </P> <P> Bullfrogs are an important item of prey to many birds (especially large herons), North American river otters (Lontra canadensis), predatory fish, and occasionally other amphibians . Predators of American bullfrogs once in their adult stages can range from 150 g (5.3 oz) belted kingfishers (Megaceryle alcyon) to 1,100 pound American alligators (Alligator mississippiensis). The eggs and larvae are unpalatable to many salamanders and fish, but the high levels of activity of the tadpoles may make them more noticeable to a predator not deterred by their unpleasant taste . Humans hunt bullfogs as game and consume their legs . Adult frogs try to escape by splashing and leaping into deep water . A trapped individual may squawk or emit a piercing scream, which may surprise the attacker sufficiently for the frog to escape . An attack on one bullfrog is likely to alert others in the vicinity to danger and they will all retreat into the safety of deeper water . Bullfrogs may be at least partially resistant to the venom of copperhead (Agkistrodon contortrix) and cottonmouth (Agkistrodon piscivorus) snakes, though these species are known natural predators of bullfrogs as are northern water snakes (Nerodia sipedon). </P> <P> The American bullfrog provides a food source, especially in the Southern and some areas of the Midwestern United States . The traditional way of hunting them is to paddle or pole silently by canoe or flatboat in ponds or swamps at night; when the frog's call is heard, a light is shone at the frog which temporarily inhibits its movement . The frog will not jump into deeper water as long as it is approached slowly and steadily . When close enough, the frog is gigged with a multiple - tined spear and brought into the boat . Bullfrogs can also be stalked on land, by again taking great care not to startle them . In some states, breaking the skin while catching them is illegal, and either grasping gigs or hand captures are used . The only parts normally eaten are the rear legs, which resemble small chicken drumsticks and can be cooked in similar ways . </P>

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