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Green Frog

Lithobates clamitans (Latreille ex Sonnini de Manoncourt & Latreille 1801)

Description

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Rana clamitans is a medium to large bodied frog. Adults in Georgia attain a body length of 86 mm in males and 87 mm in females while those in the north reach 103 mm in males and 105 mm in females. There is a similar clinal increase in body size from low to high altitudes. Dorsal coloration varies extensively, from brown, bronze, or olive to green, bicolor or bluish. The dorsum may have spots, blotches, or vermiculations of dark pigment, but such markings are not present on all individuals. The dorsolateral folds are distinct. Venter is white, sometimes with gray mottling on the throat, jaw margin and hind limbs. The outer surface of the limbs is barred or nearly so. The side of the face is colored bronze or green. There is no light line present on the upper jaw. Toes are webbed extensively, but not to the tips of digits III,IV,V. In males the tympanum is larger than the eye, the thumb and forelimb are enlarged, and the lateral vocal sacs are not externally visible. The skin of northern males is slightly rough and the throat is yellow. R. c. clamitans and R. c. melanota are subspecies.(image, http://amphibiaweb.org/images/sound3.gif) Hear calls at the Western Sound Archive (http://content.lib.utah.edu/cdm4/item_viewer.php?CISOROOT=/wss&CISOPTR=959&CISOBOX=1&REC=1).

Reference

Stewart, M. M. (1963). ''Rana clamitans.'' Catalogue of American Amphibians and Reptiles. American Society of Ichthyologists and Herpetologists, 337.1-337.4.

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Distribution and Habitat

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Found from the northern shore of the Gulf of St. Lawrence to central Florida, and from the Atlantic Coast to eastern Texas and southeastern Manitoba. Notably absent from the central Illinois Prairie. Found from the coastal lowlands to elevations of more than 1950m. Introduced populations have been established in Newfoundland, Utah, Washington and British Columbia.
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Habitat

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Green frogs are found in a wide variety of habitats that surround most inland waters, such as: swamps, wooded swamps, ponds, lakes, marshes, bogs, banks of slow moving rivers and streams, oxbow lakes, sloughs, and impoundments. Juveniles may disperse into wooded areas or meadows during times of rain. Green frogs overwinter in the water usually buried in the substrate.

Habitat Regions: temperate ; terrestrial ; freshwater

Terrestrial Biomes: taiga ; savanna or grassland ; forest

Aquatic Biomes: lakes and ponds; rivers and streams

Wetlands: marsh ; swamp ; bog

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Merritt Gillilland, Michigan State University
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Associations

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Green frogs are preyed upon by a variety of animals. Tadpoles and eggs are eaten by leeches, dragonfly larvae, other aquatic insects, fish, turtles, and herons. Adult frogs are eaten by larger frogs, turtles, snakes, herons, other wading birds, raccoons, otters, mink, and humans.

Green frogs often look much like mink frogs where the two species occur together. This may be a form of mimicry because mink frogs have a musky skin secretion that makes them foul tasting to many predators. Green frogs do not have a foul taste, so may be taking advantage of their resemblance to mink frogs to avoid being preyed upon.

Known Predators:

  • leeches (Hirudinea)
  • dragonfly larvae (Odonata)
  • other aquatic insects (Insecta)
  • fish (Actinopterygii)
  • turtles (Testudines)
  • herons (Ardeidae)
  • snakes (Serpentes)
  • larger frogs (Anura)
  • other wading birds (Ciconiiformes)
  • raccoons (Procyon lotor)
  • norther river otters (Lontra canadensis)
  • American minks (Neovison vison)
  • humans (Homo sapiens)

Anti-predator Adaptations: mimic

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Morphology

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Green frogs are green, greenish brown, brownish, yellowish green and olive, with some rare individuals being blue. They are generally brighter in front with small irregular black spots. Their legs have dark transverse bands. They are yellowish or white below, and males usually have a bright yellow throat. The tympanum (eardrum) is large; in males the tympanum is much larger than the eye and females tend to have a tympanum the same size as the eye. The dorso-lateral ridge is well defined and extends from the back of the eye posteriorly down the body. The toes are well webbed and the first fingers do not extend beyond the second. The tibia and femur are equal to ½ of the body length, which is 7.5 to 12.5 cm for adults.

Range length: 7.5 to 12.5 cm.

Other Physical Features: ectothermic ; bilateral symmetry

Sexual Dimorphism: sexes shaped differently

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Life Expectancy

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Average lifespan in the wild is unknown, but captive animals can live to 10 years.

Range lifespan
Status: captivity:
10 (high) years.

Range lifespan
Status: wild:
6 (high) years.

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Untitled

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One population of green frogs is known as 'bronze frogs.' They are usually bronze or brownish in color and have fairly plain markings. They also tend to be smaller than other green frogs. Bronze frogs are found in the southeastern United States.

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Merritt Gillilland, Michigan State University
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Distribution

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Green frogs (Lithobates clamitans clamitans) are native only to the Nearctic region. They are found in the United States and Canada from Maine and the Maritime provinces of Canada through the Great Lakes region and into western Ontario and Oklahoma, south to eastern Texas, east into northern Florida and extending up the entire east coast of the United States.

Biogeographic Regions: nearctic (Native )

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Trophic Strategy

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Green frogs are primarily carnivores and eat a wide variety of insects and other invertebrates from both land and water, such as slugs, snails, crayfish, spiders, flies, caterpillars, butterflies, and moths. They also eat other vertebrates, such as small snakes and frogs. Green frogs practice "sit and wait" hunting and therefore eat whatever comes within reach. Tadpoles mainly eat diatoms, algae, and tiny amounts of small animals such as zooplankton (copepods and cladocerans).

Animal Foods: amphibians; reptiles; insects; terrestrial non-insect arthropods; mollusks; terrestrial worms; aquatic crustaceans; zooplankton

Plant Foods: algae

Primary Diet: carnivore (Eats non-insect arthropods); herbivore (Algivore)

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Associations

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Green frogs are common and abundant and serve as a food source for many other animals. They also eat large quantities of insects and other animals, thus impacting their populations.

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Benefits

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Green frogs on occasion are harvested for food consumption, generally known as "frog legs". They are used by the scientific community in research and for educational purposes in biology classrooms from both high schools and colleges.

Positive Impacts: food ; research and education

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Benefits

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There are no known negative effects of green frogs.

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Life Cycle

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Eggs hatch in 3 to 7 days. After hatching, green frog tadpoles are usually green with small black dots and often have yellow bellies. It can take them anywhere from 3 to 22 months to begin metamorphosis into full grown frogs. Some undergo this transition before the winter, but many tadpoles go into hibernation and wait until the spring to transform. Green frogs reach their maximum size when they are 4 to 5 years old.

Development - Life Cycle: metamorphosis

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Conservation Status

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Green frogs are abundant throughout all of their range. Although limb deformities and other abnomalities have been reported in green frog populations, possibly as a result of water contamination, they are still numerous and widespread.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Behavior

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Green frogs produce as many as six different calls. Males attracting a mate give an advertisement call and a high-intensity advertisement call. Their advertisement call has been compared to the pluck of a loose banjo string. Male frogs defending a territory from an intruding male usually give aggressive calls and growls. The release call is given by non-receptive females and by males accidentally grabbed by another male. Finally, the alert call is given by males and females when startled or attacked by a predator.

Green frogs have an excellent sense of vision and use this to detect and capture prey.

Communication Channels: acoustic

Perception Channels: visual ; acoustic

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Reproduction

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Female green frogs choose their mates based on the desirability of their territories for egg laying. Satellite males may also be present during the breeding period of green frogs. A satellite male is described as a smaller male, unable to acquire and defend territories, and it is often found in areas protected by a larger male. The satellite male will wait for the opportunity to mate with a female that is responding to the larger more dominant male frog's vocalizations.

Mating System: polygynous

Breeding takes place in late spring; variations in temperature and region can influence actual breeding times. The breeding season is 1 to 3 months long and occurs in a variety of habitats, such as swamps, ponds, marshes, bogs, and slow moving streams. Once a female has chosen a male, amplexus will begin. During amplexus, 1000 to 7000 eggs may be laid. The egg masses float on the water surface or hang from emergent aquatic vegetation. Wells (1976) has shown that multiple egg clutches are possible, the second egg clutch is on average smaller, with 1000 to 1500 eggs. Eggs hatch in 3 to 7 days and will complete the tadpole stage of development in 3 to 22 months.

Breeding interval: Green frogs can have two or more clutches per season, with the second clutch producing significantly fewer eggs.

Breeding season: Green frogs breed in late spring.

Range number of offspring: 1000 to 5000.

Range time to hatching: 3 to 5 days.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous

Average age at sexual or reproductive maturity (male)
Sex: male:
730 days.

Average age at sexual or reproductive maturity (female)
Sex: female:
730 days.

Female green frogs nurture their eggs inside their bodies before they are laid and fertilized. Once the eggs are laid, there is no further parental involvement in their development.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female)

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Gillilland, M. 2000. "Lithobates clamitans clamitans" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Lithobates_clamitans_clamitans.html
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Lithobates clamitans

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Lithobates clamitans[5] or Rana clamitans,[2][6][7] 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.

These frogs, as described by their name, typically have varying degrees of green heads. These frogs display significant acts of territoriality, with males being the primary actors. Male green frogs use this technique against other male frogs in addition to other intruders that might have interest in nearing their territory. Territoriality also plays a role in mating, as females favor males who are strong in this field and exhibit strong mating calls. Male green frogs use four different types of breeding calls to attract potential female mates. Predators that attack green frog's eggs include bugs such as beetles, water bugs, and water scorpions. Adult frogs are typically threatened by several types of birds.

Taxonomy

Lithobates clamitans is a member of the true frog family Ranidae and genus Lithobates. Litho- meaning stone, a rock climber. Originally from genus Rana until systematic revision, features of the genus are true frogs with slim waist and wrinkled skin, found across much of Eurasia and North America.

Subspecies

The two recognized subspecies of L. clamitans are:

Description

This species is a mid-sized true frog. Adult green frogs range from 5–10 cm (2.0–3.9 in) in body length (snout to vent, excluding the hind legs). The typical body weight of this species is from 28 to 85 g (0.99 to 3.00 oz).[8][9] The sexes are sexually dimorphic in a few ways: mature females are typically larger than males, the male tympanum is twice the diameter of the eye, whereas in females, the tympanum diameter is about the same as that of the eye, and males have bright yellow throats. The dorsolateral ridges, prominent, seam-like skin folds that run down the sides of the back, distinguish the green frog from the bullfrog, which entirely lacks them.

Green frogs usually have green heads while the body is brown, gray, or dark green. The green head can be more or less prominent on certain individuals, with some frogs only having green on the side of their heads while other frogs are green all the way down their back. The belly is white with black mottling. Male green frogs in breeding condition have yellow throats. Green frogs are darker colored on colder days to help absorb heat. Green frogs can sometimes be blue due to a genetic mutation known as axanthism that prevents the frog from producing yellow pigments (yellow and blue pigments together make the color green).

Green frog tadpoles are olive green and iridescent creamy-white below. Metamorphosis can occur within the same breeding season or tadpoles may overwinter to metamorphose the next summer.[9]

Habitat and Distribution

Green frogs are associated with bodies of water and have been found in a variety of habitats, living at the margins of shallow freshwater ponds, road-side ditches, lakes, swamps, and streams, and of vernal pools and other temporary bodies of water though less so than other frogs.[1][8][9][10][11] They maintain small home ranges around these water sources and spend about a third of their time foraging for resources (especially in regions of abundant leaf litter and dense vegetation), returning to the water for refuge.[8][10] Their habitat has also been impacted by human interaction via the development of roads, buildings, and other infrastructure and agriculture which involves the destruction of their habitat. However, if there is abundant and quality habitat nearby, green frogs have the capability to flee from deforestation and are also somewhat tolerant of said destruction. When attempting to flee from the destruction of their habitat, Green frogs tend to move primarily among three distinct types of aquatic habitats: ephemeral wetland, stream, and swamp. Additionally, green frogs select for increased soil moisture, fine woody debris, and fewer trees with water cover being the most important factor emphasizing the fact that they tend to inhabit areas near water and with open environments in order to survive.[10]

The green frog is a widespread species native to North America, mainly occurring throughout eastern North America from the St. Lawrence River Valley in southeastern Canada to Northern Florida and Eastern Texas.

Habitat Loss

Due to increasing destruction of their habitat, deforestation, climate change, diseases, and chemical contaminants, amphibian population decline and extinctions may be as high as 211 times the background extinction rate.[12] Both water and air temperatures play a major role in timing and rates of breeding, larval development, time-to-time metamorphosis, size-at-metamorphosis, growth, and physiological parameters. There is experimental data present that details how organisms are more sensitive to contaminants when there is variation in temperature, which explains how chemical contamination can greatly impact the development of these frogs. Chloride in particular affects the development of the Green Frog. Vast exposure to chloride can result in many larvae having broken tails, swollen body cavities, a loss of pigment, and behavioral abnormalities. As the temperature increased in the environment, the frogs had lower time-to-mortality and significantly higher hazard when compared to the controls. This shows how temperature directly affects sensitivity to chemicals and thereby the development of the Green Frog by making their habitat more dangerous. According to the Maryland Biological Stream Survey, stormwater ponds which are a main example of a breeding habitat in Maryland can experience chloride concentrations of up to 3250 mg/L, which shows how there are several factors within their habitat affecting the survival rate of these frogs.

Diet

Green frogs will attempt to eat any mouth-sized animal they can capture, including insects, spiders, fish, crayfish, shrimp, other frogs, tadpoles, small snakes, slugs,[11] and snails. Green frogs practice "sit and wait" hunting and therefore eat whatever comes within reach.[11] Tadpoles will eat nearly anything organic, including diatoms, algae, and tiny amounts of small animals such as zooplankton (copepods and cladocerans).[11]

Reproduction

Green frog pair in amplexus: Note large tympanum of male, on top, and small tympanum of the female

Males become sexually mature at one year, females may mature in either two or three years.[9] Males will establish breeding territories and maintain them throughout the entirety of the breeding period,[11] with the season occurring from spring through summer,[8] with variations depending on location and temperature.[11] There is a strong positive correlation between temperature and detection. [13] During this breeding period, an egg clutch consisting of 1000 to 7000 eggs[11] is laid in surface films about 15–30 cm in diameter and are attached to vegetation in shallow water[14] in order to protect the eggs from predators. Females may sometimes lay two clutches of eggs in a single season, with their size reaching a maximum of 98–105 mm. Females who were ready to mate typically came into male territories and assumed a low posture to demonstrate the clear power difference between the two (the lower posture emphasizes their subordination as does the fact that they come to the males once ready to mate). However, females did still exhibit selection when choosing a male as the process of choosing a mate typically took 2 to 3 days. In this case, females tend to favor males who exhibit territoriality and have strong mating calls (the basis for this is selfish as it lies in the female's desire for the greatest reproductive success and the best traits to be passed down to their children). Once a female was a few centimeters in front of the male, she would back her body into his and once physical contact was reached, the males would clasp the females and fertilization would begin. There are several instances where females will not be clasped due to the stimuli which initiate amplexus (when the male clasps the female from the back) not being created. Once fertilization occurred, almost all of the eggs were deposited into the resident male's territory (not the satellite male's, implying that polyandry for the female is not a common practice in this species) which promotes protection for the offspring.

Tadpole

Research show that wild green frogs, both living in contaminated suburban backyard ponds and also in relatively pristine forested ponds, can switch sexes.[15] This sex reversal appears to be a natural condition but it is currently unknown whether these wild sex-reversed green frogs are able to breed.

After the eggs are deposited into the resident's male territory, development begins to occur. The typical larval life of green frogs is between 70 and 360 days depending on the time of year in which the eggs were laid. The season of growth in adult frogs (where snout-to-vent measurements increased the most) is primarily between mid-May and mid-September. This mainly correlates with the mean monthly temperature and the amount of time that the temperature is favorable for feeding. Sexual maturity is reached about a year after metamorphosis. However, frogs do not become sexually active until the year after sexual maturity is attained. There is no sexual dimorphism in size in the fully mature frog.[16]

Home Range and Territoriality

Regarding territoriality, males will often physically wrestle with one another in order to defend their territory.[17] Resident male frogs would also create loud splashing noises by jumping up and down in the water or by sitting in one place and rapidly kicking his hind legs. This act of both jumping up and down and creating a distinct noise serves many different purposes. Firstly, males would leap high out of the water to patrol their territory borders in order to locate intruders, and would then proceed to make a loud splashing noise to both mark their territory and scare off intruders. These splashing displays were also performed in response to intruders entering their territories and by victorious males pursuing their opponents once again emphasizing another form in which these frogs maintain their dominance.[18][17][14]

If both the advertisement calls and acts of splashing did not deter the intruder, then more aggressive acts were performed by the resident male. The resident male would retaliate by jumping at the frog and chasing him away or attacking the intruder and immediately clasping him around the head, waist, or one leg. While most attacks were directed towards males in an act of defending territory, some attacks were directed towards females. This is due to the fact that resident males cannot visually see the difference between females and males and therefore might mistake a female going through his territory as an intruder male. This results in females adopting a similar position to the satellite males when traversing through a resident male's territory.[18][17][14]

Most interactions among the males of this species involve splashing and vocalizations to scare off intruders or satellite males. However, once there were two males who would present equal competition to one another thereby creating real contests for possession of lands, wrestling bouts ensued. In the beginning, two males would approach one another in high posture demonstrating the equal status between the two. Once these frogs were only a few centimeters apart, they would tip their heads at an angle which would expose their bright yellow throat to the opponent. Soon after, the wrestling would begin and each frog would jump, swim, or splash at each other to attempt to secure a strong hold on the opponent. Eventually, once each frog clasped the other around the pectoral region, they would engage in a pushing contest until the other fell on its back. Once the frog fell, the dominant frog would hold his opponent under water and squeeze him until they admit defeat and free themselves from the hold.[18][17][14]

Behavior

Vocalizations

To emphasize their territory during breeding season, males advertise their positions with vocalizations and exhibit aggressive behavior including chases and jump attacks. Males have four main vocalizations used to maintain their territories. The first type of call is the advertisement call, which functions to advertise a male's position to other males and to prospective mates. The distinctive call sounds like a plucked loose banjo string,[11] usually given as a single note, but sometimes repeated.[19] Many studies show that aggressive behavior is evoked from other male frogs in response to this call.

The second type of call is similar to the first but is more urgent. This call is used in response to a disturbance in the territory. It is thought to demonstrate dominance because it is often given by the winners of wrestling bouts when chasing the losers out of their territories.

The third type of call is often directed towards others in an agonistic encounter. It is usually the first call produced when a frog's territory has been invaded and while the male approaches the intruder. Consequently, this call antagonizes more aggressive behavior since there were often physical bouts between the intruder and owner of the territory. This is different from the second type of call, because the second call serves as more of a warning call while this call meant that violence would follow.

Finally, the fourth type of call is produced during wrestling bouts and given by the male that is winning the fight. Additionally, there is also a fifth call type that both males and females use which serves as a release call when an individual is clasped by another frog. For males, it was released when they were losing wrestling bouts, while for females, it was released both when non-gravid females were being clasped by males and when females were ready to be released after completing oviposition. Both the females and losing males releasing the same call emphasizes the fact that males without territory or males who lost to other males are seen as weaker and subordinate in this species.[19]

Movement and Posture

Males often move from territory to territory since they occupy several different territories to increase their mating appeal to females. Males that do not have a territory for the breeding season often move into other males' territory and become satellite males. Satellite males use these new territories to intercept females who are responding to the call of territory owners, demonstrating a type of sexual coercion. In contrast, females did not exhibit any particularly aggressive interactions since they normally spent the day hiding in vegetation while at night they foraged for resources.[20][19][14]

Green Frog

Males demonstrating territorial behavior often presented different postures emphasizing different aspects of their physical appearance when compared to satellite males. Territorial males maintain a high posture, with the lungs inflated and only the lower parts of the limbs under water. These frogs tilt their head at a certain angle to allow their bright yellow throat to be exposed which is an act of presenting dominance and marking their own territory. They maintain this posture throughout the entire day (calling time or not). In contrast, satellite males assume a low posture with only the top of the head and eyes above the water's surface. Since their main focus is to steal the territory from the dominant male when he leaves to go to his other territories, the satellite males assume a more sneaky position since they will often stalk the resident male and move cautiously through the territory. This low position also decreases the chances of the satellite male being attacked by the resident male since they were seen as being subordinate/below the resident male.[20][19][14]

Predation and Enemies

Due to their environment being so dependent on water, pathogens, predators, and other deadly problems often trouble the Green Frog. The fungal pathogen Batrachochytrium dendrobatidis (Bd) has been involved with the decline of several amphibian populations, one being the Lithobates Clamitans. Bd kills amphibians by interfering with external water exchange, which causes an imbalance with ion exchange, thereby leading to heart failure. An important factor in mediating the interaction between amphibians and Bd is temperature. If the temperature is beyond 30 degrees Celsius, then Bd will not survive, while the optimal temperature for Bd is 17-23 degrees Celsius. Furthermore, seasonal temperature variation can cause differences in immunity to this pathogen. For the Green Frog species, the prevalence of Bd was significantly higher in closed canopy streams, while infection intensities were higher in emergent wetlands. This could be due to prevalence being directly related to lower temperature habitats which are present in the canopy streams.[21]

Green Frogs historically have several types of predators. Firstly, their eggs are eaten by turtles, tadpoles are eaten by diving beetles, giant water bugs, and water scorpions. They are also preyed upon by ducks, herons, and crows.[22]

Anti-Predatory Measures

Green Frogs have also developed certain anti-predatory measures in order to survive. One example of an anti-predatory measure developed by several different organisms is the use of chemical cues. Chemicals are released by predators and prey throughout the entire duration of a predation event thereby allowing the prey to detect the presence of predators through chemicals subconsciously released by the predators. Several research studies have demonstrated that aquatic prey tend to avoid chemical cues as their form of an anti-predatory measure. Specifically for the tadpoles of the Green Frog, they reacted with spatial anti-predator behavior (distancing themselves from the chemical cues), when only exposed to both Anax kairomones and conspecific alarm cues together. Experimenters hypothesize that presence of both of these cues are needed because the costs of fleeing their habitat may result in a massive loss of foraging opportunities. If they choose to respond to a certain cue that is not strong or reliable, then they are losing a vast amount of resources. Thus, when they choose to demonstrate spatial avoidance, there must be multiple chemical cues present in order for the benefits to outweigh the risks.[23]

Typically, when encountering predators, animals tend to develop anti-predator traits in order to promote reproductive success. Consequently, these traits will be passed down throughout generations until the predator develops a new trait to counteract this measure thereby creating an arms race between the predator and the prey. Another consequence of this type of evolution is subsets of a species developing new traits due to the different exposure of predators due to their different environments (diverging evolution). Regarding the Bronze Frog (which is a subspecies of the Green Frog), when present in ponds inhabited by invertebrate predators, the tadpoles may develop small bodies and large tail muscles in order to increase fast-start locomotor performance to escape from their predators. Consequently, the presence of fish and invertebrate predators plays a large role in size, shape, and swimming performance of the tadpoles of the Green Frog. As a result, this can lead to some morphological differences between the subspecies within the Green Frog, which highlights divergent natural selection and adaptive phenotypic plasticity.[24]

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Lithobates clamitans: Brief Summary

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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.

These frogs, as described by their name, typically have varying degrees of green heads. These frogs display significant acts of territoriality, with males being the primary actors. Male green frogs use this technique against other male frogs in addition to other intruders that might have interest in nearing their territory. Territoriality also plays a role in mating, as females favor males who are strong in this field and exhibit strong mating calls. Male green frogs use four different types of breeding calls to attract potential female mates. Predators that attack green frog's eggs include bugs such as beetles, water bugs, and water scorpions. Adult frogs are typically threatened by several types of birds.

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