Pickerel frog | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Amphibia |
Order: | Anura |
Family: | Ranidae |
Genus: | Lithobates |
Species: | L. palustris |
Binomial name | |
Lithobates palustris (Le Conte, 1825) | |
Pickerel frog range | |
Synonyms | |
Rana palustrisLeConte, 1825 Contents |
The pickerel frog (Lithobates palustris, formerly Rana palustris) is a small North American frog, [1] [2] characterized by the appearance of seemingly "hand-drawn" squares on its dorsal surface.
The pickerel frog is a medium sized gray or tan frog marked with seven to twenty-one irregular rectangular dark brown spots which are oriented in two columns down its back. [3] The distinctive rectangular spots of the pickerel frog may blend together to form a long rectangle along the back. All leopard frogs have circular spots. In addition, pickerel frogs have prominent dorsolateral ridges that are unbroken. Another important distinguishing mark is the orange or yellow flash pattern found on the inner surface of the hind legs of pickerel frogs. The frog must be picked up to examine this, as the legs cover the coloration otherwise. The plains leopard frog (Lithobates blairi) exhibits this coloration as well, but the dorsolateral ridges are interrupted and inset medially in that species. The front toes of pickerel frogs are not webbed, a morphological characteristic for some frogs of the genus Rana and some frogs of the genus Lithobates . This allows pickerel frogs to be fit for terrestrial life.
Pickerel frogs display sexual dimorphism; the females are typically larger and darker in color than the males. [4] During the summer and breeding season males can be recognized by their swollen thumbs. Males also have internal vocal sacs located between the tympanum and the foreleg. In general, secondary sexual characteristic are not typically evident outside of the breeding season; therefore, pickerel frogs can be rather difficult to sex. [5]
The pickerel frog ranges in the west from much they are of Wisconsin, southeast Minnesota, eastern Iowa, through Missouri and down to eastern Texas. To the east they extend through northern Louisiana, most of Mississippi, northern Alabama, Georgia, and South Carolina to the coast. Their northern range extends into Canada in the southern reaches of Ontario, Quebec, New Brunswick, and Nova Scotia. The range is spotty through the midwestern states and a field guide should be obtained for the specifics on ranges in a particular area. This frog has also been spotted in Newfoundland and Labrador, Canada.
Pickerel frogs have varied habitats, the northern populations prefer to live near cold, clear water. They prefer rocky ravines, bogs and meadow streams, but can be found around lakes and rivers that are heavily wooded. In a study on amphibians in Canada, pickerel frogs were negatively associated with young forest stands. [6] Pickerel frogs in the southern portion of their range prefer warmer waters, like those of the Coastal Plain and floodplain swamps. They are seen most often along the edges of streams, lakes, rivers, and even flooded ditches. During the winter months they will hibernate under the silt and debris in their aquatic environments; they are usually only active from April to October. [7] When feasible, this species utilizes caves for thermal refugia during the coldest months of the year. [8] The pickerel frog is a trogloxene species, meaning they occur in caves, but are unable to complete their life cycles there. Though they are most abundant in caves during the winter, they are active deep within caves at almost any time of year. [9] When temperatures get too cold, this species will inhabit hibernacula. These hibernacula are commonly found nearby one another in the center of the cave. [10] Pickerel frogs will sometimes inhabit those same caves during hot summers. [11]
Pickerel frogs prefer cool, clear water. They breed in both temporary ponds and permanent ponds, but appear to favor ponds with long to permanent hydroperiods. In Rhode Island specifically, pickerel frog tadpoles and egg masses were found in permanent manmade rural ponds, farm ponds, and urban ponds surrounded by roads; all of the mentioned habitats were well-vegetated. [12]
Pickerel frogs typically emerge from hibernation around mid April with the majority of the frogs arriving at breeding ponds by early May. No fall reproduction has been reported for this species. [13] At the ponds, pickerel frogs are usually observed in large groups in the water. [14] Mating behavior is not much different from other ranids. The males initiate breeding by emitting their low pitched call; this call is usually so low pitched that it is often not heard during calling surveys. [15] Males are known to call while submerged. Frogs reproduce by external fertilization while engaging in a behavior called amplexus; sometimes amplexus will last more than a day or two, even after the female has deposited the eggs. [4]
Egg masses are typically laid in well-vegetated areas and are often difficult to locate. The masses superficially resemble those of wood frogs but at close inspection one can usually distinguish between the two. Pickerel frog egg masses are spherical and about the same size of a wood frog egg mass—roughly 5–10 cm in diameter—although pickerel frog egg masses contain more eggs, about 2000–3000. [4] Pickerel frog eggs are multicolored: they are dark brown on top and cream colored on the bottom. The egg masses adhere to woody or herbaceous vegetation, varying in depth from a few centimeters below the surface to four feet (1.2 m) deep. [5] Like in most amphibians egg development is temperature dependent, but pickerel frog eggs usually hatch in 11–21 days. [16]
The tadpole stage lasts roughly three months. Small pickerel tadpoles are yellowish to yellowish brown in color; as they grow their color changes to an olive green, which eventually changes to gray brown on top and cream colored underneath. Larger tadpole are often mistaken as green frogs. There are a few characteristics to aid in distinguishing between pickerel and green tadpoles. The nose of the pickerel frog tadpole is more pointed, the eyes are closer together, and the nostrils are closer to the edge of the nose. [17]
This is the stage where frogs have all four limbs and are able to walk on land, but still have their tails. They are not quite juvenile frogs. Metamorphs are roughly 2.6 cm long, but they are nearly as agile as the adult and juvenile when they emerge from the ponds. They are often mistaken for the closely related leopard frog. Larger tadpoles complete metamorphosis more efficiently because they used less energy total for the process than smaller tadpoles but energy costs are actually positively correlated with tadpole mass and duration of metamorphosis. [18]
The pickerel frog's diet consists of ants, spiders, various bugs, beetles, sawfly larvae, and other invertebrates. In order to catch their prey pickerel frogs will often search grassy areas next to bodies of water. [3]
In case of attack, pickerel frogs have an excellent defense mechanism: they emit skin secretions which are irritating to people and toxic to some predators; making the pickerel frog the only poisonous frog native to the United States. [19] A peptidomic analysis of the defensive skin secretion have established the presence of canonical bradykinin and multiple bradykinin-related peptides. [20] Due to its poison, most mammals, birds, snakes and other frogs will leave the pickerel frog alone. The skin secretions of a stressed pickerel frog are known to be toxic to other frogs, as many a novice frog catcher has found when he finds only the pickerel frog still alive in his bucket. These secretions can also be moderately irritating if they come in contact with the eyes, mucous membranes, or broken skin.
The tadpole of this species is considered unpalatable to many species that would commonly predate on tadpoles. They also exhibit behaviors to avoid predation. To avoid fish, the tadpoles will move to stream margins in order to make them inaccessible to the fish. The tadpoles will also reduce activity after sensing a fish's chemical cues. [21]
The pickerel frog's poisonous secretions cannot stop all creatures; green frogs, bull frogs, northern water snakes, eastern ribbon snakes, and common garter snakes are their usual predators. [22] When threatened, pickerel frogs will jump into the water and dive to the bottom to escape predators like birds and snakes.
The American bullfrog, often simply known as the bullfrog in Canada and the United States, is a large true frog native to eastern North America. It typically inhabits large permanent water bodies such as swamps, ponds, and lakes. Bullfrogs can also be found in manmade habitats such as pools, koi ponds, canals, ditches and culverts. The bullfrog gets its name from the sound the male makes during the breeding season, which sounds similar to a bull bellowing. The bullfrog is large and is commonly eaten throughout its range, especially in the southern United States where they are plentiful.
Leopard frog is a generic name used to refer to various species in the true frog genus Lithobates. They all have similar coloration: brown or green with spots that form a leopard pattern. They are distinguished by their distribution and behavioral, morphological, and genetic differences. The range of the various species of leopard frogs extends from the Hudson Bay in Canada, throughout the United States, throughout Mexico and other parts of Central America, and possibly the very northern section of South America.
Lithobates pipiens formerly Rana pipiens, commonly known as the northern leopard frog, is a species of leopard frog from the true frog family, native to parts of Canada and the United States. It is the state amphibian of Minnesota and Vermont.
Lithobates sylvaticus or Rana sylvatica, commonly known as the wood frog, is a frog species that has a broad distribution over North America, extending from the boreal forest of the north to the southern Appalachians, with several notable disjunct populations including lowland eastern North Carolina. The wood frog has garnered attention from biologists because of its freeze tolerance, relatively great degree of terrestrialism, interesting habitat associations, and relatively long-range movements.
Rana is a genus of frogs commonly known as the Holarctic true frogs, pond frogs or brown frogs. Members of this genus are found through much of Eurasia and western North America. Many other genera were formerly included here. These true frogs are usually largish species characterized by their slim waists and wrinkled skin; many have thin ridges running along their backs, but they generally lack "warts" as in typical toads. They are excellent jumpers due to their long, slender legs. The typical webbing found on their hind feet allows for easy movement through water. Coloration is mostly greens and browns above, with darker and yellowish spots.
The foothill yellow-legged frog is a small-sized frog from the genus Rana in the family Ranidae. This species was historically found in the Coast Ranges from northern Oregon, through California, and into Baja California, Mexico as well as in the foothills of the Sierra Nevada and southern Cascade Range in California. The foothill yellow-legged frog is a Federal Species of Concern and California State Endangered. A federal rule to list four out of six extant distinct population segments (DPS) under the Endangered Species Act was proposed in December 2021.
The Columbia spotted frog is a North American species of frog. It is green to brown in color with spots on the dorsal surface. The belly and upper lip are white in color. Individuals can be distinguished from other Rana species by their shorter back legs, narrow snout, and upturned eyes. Since they spend most of their time in the water, they also have more webbing in their hind feet than similar species. Although not threatened, this animal has been studied as a model species for the effects of habitat fragmentation.
The mink frog is a small species of frog native to the United States and Canada. They are so named for their scent, which reportedly smells like a mink. The scent is more akin to that of rotting onions to those unfamiliar with mink. It is also sometimes referred to as the north frog.
Lithobates sphenocephalus or Rana sphenocephala, commonly known as the southern leopard frog, is a medium-sized anuran in the family Ranidae. The southern leopard frog is one of the 36 species currently or formerly classified in the Rana genus found in North America. It is native to eastern North America from Kansas to New York to Florida. It is also an introduced species in some areas. This species lives in cool, clear water in the north, whereas in the south it occurs in warmer turbid and murky waters of coastal and floodplain swamps, twilight zones of caves, and abandoned mines.
The Plains leopard frog is a spotted frog found in North America. It is sometimes referred to as Blair's leopard frog, named after the noted zoologist and University of Texas professor, Dr. W. Frank Blair.
The crawfish frog is a medium-sized species of frog native to the prairies and grasslands of the central United States. It gets its name because it inhabits the burrows of crayfish for most of the year. They have defined golden or black circles all over their body.
The Rio Grande leopard frog is a species of aquatic frog native to the southern United States in Texas and New Mexico, and south through Mexico and Central America. It is also sometimes referred to as the Mexican leopard frog. The epithet berlandieri is in honor of the naturalist Jean Louis Berlandier, who worked for the Mexican government on one of the first biological surveys of Texas.
The northern red-legged frog is a species of amphibian whose range is the coastal region stretching from southwest British Columbia to southern Mendocino County in Northern California, and is protected in Oregon and California. As a member of the genus Rana, this species is considered a true frog, with characteristic smooth skin and a narrow waist. This frog requires still waters for breeding, and is rarely found at any great distance from its breeding ponds or marshes.
Lithobates, commonly known as the bullfrogs, is a genus of true frogs, of the family Ranidae. The name is derived from litho- (stone) and the Greek bates, meaning one that treads on rock, or rock climber. As presently defined, it includes many of eastern North America's most familiar aquatic frog species, including the American bullfrog, green frog, and the leopard frogs.
The Cascades frog is a species of frog in the family Ranidae found in the Pacific Northwest, mainly in the Cascade Range and Olympic Mountains.
The river frog is a species of aquatic frog in the family Ranidae. It is endemic to the southeastern United States. Its natural habitats are temperate rivers, swamps, freshwater lakes and freshwater marshes. It is threatened by habitat loss.
The Mississippi gopher frog, also known commonly as the dark gopher frog, the dusky gopher frog, and the St. Tammany gopher frog, is a critically endangered species of frog in the family Ranidae. The species is endemic to the southern United States. Its natural habitats are temperate coastal forests and intermittent freshwater marshes. This secretive frog is on average 3 in (8 cm) long, with a dark brown or black dorsal surface covered in warts. It is a federally listed endangered species of the United States.
The carpenter frog is a species of true frog found on coastal plain of the Atlantic coast of the United States between central New Jersey and northeastern Florida.
Lithobates clamitans or Rana clamitans, commonly known as the green frog, is a species of frog native to eastern North America. The two subspecies are the bronze frog and the northern green frog.
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