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Wood Frog(''Lithobates sylvaticus or Rana sylvatica'') is a terrestrial frog found throughout North America. It can be found in the up into the north most boreal forests of Canada down to the Appalachian Mountains of the United States. They belong to the Order Anura, Family being Ranidae.  
The Wood Frog, otherwise known as ''Lithobates sylvaticus'', is a terrestrial frog found throughout North America [5]. In Greek '' Litho'' translates to "a stone", ''bates'' translates to "one that walks", and ''sylvaticus'' meaning "amidst the trees" [6]. They belong to the Order ''Anura'' and the Family ''Ranidae'' [2]. This species of frog is common and is not currently under any threat of extinction [5].
== Description ==
== Description ==
[[File:wood-frog.jpg]]


[[File:wood-frog.jpg|260px|thumb|left|This is a photo of an adult Wood frog.]]


The Wood frog is a comparatively small frog. Fully grown adults are 1.5 to 3.25 inches in length [5]. Females are typically larger and more brightly colored than their male counterparts [5]. They can differ in color, but bodies typically range from a light tan to a dark brown [4]. Their most distinct feature is the coloration around their eyes. The Wood frog has two black markings that extend back from their eyes, resembling a mask [6]. The underbelly is white and sometimes has small grey marks [4]. This frog has two distinct ridges that run down their back. These ridges are known as Dorsolateral folds [6].


The wood frog is a small frog ranging in size from an inch to three and a half inches in length as an adult. Females are typically larger than males and tend to be more brightly colored. It can be brown, tan to rust colored with distinct black patches over it's eyes that resemble a mask.The underbelly a greenish yellow Coloration may vary with individual depending on conditions.  Two distinct ridges run down it's back on each side.
[[File:WFTAnatomyBW.jpg|260px|thumb|left|Anatomical diagram of an adult Wood frog.]]


== Range and Habitat  ==


== Distribution and Habitat  ==
[[File:woodfrogmap.gif|200px|thumb|left|This map shows the geographical range for ''Lithobates sylvaticus''.]]


[[File:woodfrogmap.gif]]
Wood frogs have a very large range. They are found in Canada and North America [5]. Their range goes as far south as the Appalachian mountains and as far north as Alaska [6]. They can also be found in smaller populations in Alabama and Idaho [5]. The Wood frog is the only frog that lives in the Artic Circle, this is due to their ability to freeze [5].


Wood frogs typically like both deciduous and coniferous forests [6]. They gravitate towards forests with a closed canopy to keep out sunlight and keep in moisture [2]. This species likes lots of leaf litter and wood debris on the forest floor for shelter [4]. Especially in the winter, Wood frogs can go upland and seek refuge in the leaf litter while they hibernate [3]. When they are not breeding, they can be found in an moist forested areas, ravines, bogs or forested swamps. When spring comes they migrate into forested wetlands or other protected bodies of water to breed [2].


During mating season, these frogs find temporary pools of water of [[Vernal Pools|vernal pools]] [6]. These can be any cut off water sources like streams or ponds, and can even be in ditches. These are preferably free of fish to increase survivability of the offspring [6]. Wood frogs are diurnal and are rarely seen at night but often heard in loud choruses during mating season [5].
== Cold Tolerance ==
Wood frogs are one of the only species of frog to live in the Artic Circle, this is due to their ability to freeze [4]. These frogs "freeze over" in the winter, this serves as hibernation [5]. The freezing process works by releasing large amounts of glucose into their bloodstream, this keeps their body cells from freezing, but not their other bodily fluids [4]. The distribution of liver glycogen enhances the survival of cells, tissues, and organs. This was seen by experimentally adding additional glucose to the Wood frog which increased its tolerance to freezing [1]. This glucose distribution raises the osmotic pressure of the body fluids, which in turn reduces the amount of ice that forms at any given temperature [1]. The Wood frog also creates and antifreeze using their urea [5]. These cryoprotectants keep the water within their cells from freezing because this would indeed kill them [5]. As winter ends the frogs will begin to thaw and begin the breeding process [5].


Wood Frogs can be found through most of Canada and Alaska and as far south as northern Georgia. In the United States they are mostly found in the Northeastern states.
Wood frogs are forest dwelling amphibians. During the summer months they can be found in an moist forested areas, ravines,bogs or forested swamps During the winter months the seek refuge in leaf litter in the uplands. When spring comes they will migrate into forested wetlands or other protected bodies of water to breed. This migration can be somewhat explosive with large numbers migrating.
For breeding these frogs find temporary pools of water of [[Vernal Pools|vernal pools]]. This can be any cut off water sources like in a stream or ponds, even in ditches. These are usually fish free to increase survivability of the offspring. Wood frogs are diurnal and are rarely seen at night but often heard in loud chores during mating seasons.


== Cold Tolerance ==
Wood frogs one of the only amphibians to inhabit the Arctic Circle. The wood frog has a freeze tolerance. This freeze tolerance is capable due to the rapid synthesis of glucose from liver glycogen and the distribution of this cryoprotective agent to cells throughout the body. This distribution enhances the survival of cells, tissues, and organs. This was seen by experimentally adding additional glucose to the frog which increases its tolerance to freezing (Costanzo et al. 1993). This glucose distribution will raise the osmotic pressure of the body fluids, which in turn reduces the amount of ice that forms at any given temperature. The extra gluclose will casue a decrease in the degree of cell shrinkage during freezing, and also works as a fermentable fuel that can be metabolized in the absence of oxygen.  The wood frog also uses urea as a cryoprotectant.  Unlike glucose, urea is accumulated during autumn and early winter, and is already localized within cells when freezing begins.  Some evidence suggests that urea is more efficacious than glucose in preventing cryoinjury (Costanzo and Lee 2005).
== Diet ==
== Diet ==
Wood Frogs are omnivores. While inhabiting the forests as adults they feed on a variety of small invertebrates that they find on the forest floor. As tadpoles they will feed on algae or detritus and even larvae of amphibians. Cannibalism has often been observed in tadpoles when starvation is the alternative.
 
As tadpoles, Wood frogs only eat algae and other frog larvae, but as they grown into their adult stages they become omnivores [4]. While inhabiting the forests, they feed on a variety of small [[invertebrates]] that they find on the forest floor. With their long tongue they can catch [[insects]] including, arachnids, worms, [[slugs]], and snails [5]. The Wood frog is not particular about its diet and will eat just about anything that's the size of its mouth [3]. These frogs are often seen as easy prey, and are eaten by snapping turtles, raccoons, skunks, coyotes, foxes, and birds [5].


== Reproduction ==
== Reproduction ==
The Wood frogs emerge from the leaf litter in late winter or early spring, usually March. The head to a nearby body of water and begin looking for a mate. The male wood frog has a short quack like mating call. Once the frogs pair the female will lay egg clutches of 300-1000 eggs. The eggs will hatch between 9 to 30 days after they are laid. Males will mature between 1 and 2 years and Females after about 3 years. Some individuals will only reproduce once in there lives, others two or three times as their life span is on average 4 years.


Wood frogs will leave their leaf litter refugee after "freezing off" to find a vernal pool for breeding [6]. This process typically begins as early as March and as late as April [4]. The male frogs will make a crocking noise to attract a mate when they are ready, this is typically at night [3]. While the male is on the back of the female they will both simultaneously release their gametes, sperm and egg, into the water [3]. The eggs are now fertilized, and can continue to grow in the water [3]. Each female can lay 1,000 to 3,000 eggs per season [5]. To prevent the eggs from drifting downstream the egg mass attaches itself to nearby vegetation [3]. It takes the eggs about one week until they hatch, once hatched they are in their tadpole stage [3]. This stage can last at least two months, and is likely to be longer if nutrient availability is low [3]. After the two months, the tadpoles have transformed into froglets [3]. These froglets are only about ten centimeters long and it takes two more years until they before adult Wood frogs [3]. After two years, the Wood frog is fully matured it may began to mate, and the process begins again [3]. Wood frogs have a life span of about 3 years [5].




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== References ==
== References ==
Berven, Keith A., and Thaddeus A. Grudzien. “Dispersal in the Wood Frog (Rana Sylvatica): Implications for Genetic Population Structure.” Evolution, vol. 44, no. 8, 1990, pp. 2047–56. JSTOR, doi:10.2307/2409614.


Conlon, J. M., et al. “Freeze Tolerance in the Wood Frog Rana Sylvatica Is Associated with Unusual Structural Features in Insulin but Not in Glucagon.” Journal of Molecular Endocrinology, vol. 21, no. 2, Oct. 1998, pp. 153–59. PubMed, doi:10.1677/jme.0.0210153.
[1] Costanzo, Jon P., et al. “Cryoprotectants and Extreme Freeze Tolerance in a Subarctic Population of the Wood Frog.” PLOS ONE, vol. 10, no. 2, Feb. 2015, p. e0117234. PLoS Journals, doi:10.1371/journal.pone.0117234.
 
[2] Integrated Taxonomic Information System - Report. (n.d.). . https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=775197.  


Costanzo, Jon P., et al. “Cryoprotectants and Extreme Freeze Tolerance in a Subarctic Population of the Wood Frog.” PLOS ONE, vol. 10, no. 2, Feb. 2015, p. e0117234. PLoS Journals, doi:10.1371/journal.pone.0117234.
[3] Preston, B. (n.d.). The Biology of the Wood Frog. Nature North. http://www.naturenorth.com/spring/creature/woodfrog/wf2.html.  


“Explosive Breeding Reduces Egg and Tadpole Cannibalism in the Wood Frog, Rana Sylvatica.” Animal Behaviour, vol. 50, no. 3, Jan. 1995, pp. 731–39. www.sciencedirect.com, doi:10.1016/0003-3472(95)80133-2.
[4] Wild things in your woods. (n.d.). . Cornell University. https://cpb-us-e1.wpmucdn.com/blogs.cornell.edu/dist/a/7804/files/2018/05/Wood-Frog-23xt0xr-11v8dab.pdf.  


Virginia Herpetological Society. http://www.virginiaherpetologicalsociety.com. Accessed 4 May 2021.
[5] Wood frog. (n.d.). . National Wildlife Federation. https://www.nwf.org/educational-resources/wildlife-guide/amphibians/wood-frog#:~:text=Wood%20frogs%20are%20found%20in,lay%20eggs%20in%20vernal%20pools.  


“Wood Frog | Vermont Center for Ecostudies.” Vermont Center for Ecostudies | Uniting People & Science for Conservation, 5 June 2014, https://vtecostudies.org/wildlife/amphibians/wood-frog/.
[6] Wood Frog. (n.d.). . Virginia Herpetological Society. https://www.virginiaherpetologicalsociety.com/amphibians/frogsandtoads/wood-frog/wood_frog.php.

Latest revision as of 09:01, 29 April 2022

The Wood Frog, otherwise known as Lithobates sylvaticus, is a terrestrial frog found throughout North America [5]. In Greek Litho translates to "a stone", bates translates to "one that walks", and sylvaticus meaning "amidst the trees" [6]. They belong to the Order Anura and the Family Ranidae [2]. This species of frog is common and is not currently under any threat of extinction [5].

Description

This is a photo of an adult Wood frog.

The Wood frog is a comparatively small frog. Fully grown adults are 1.5 to 3.25 inches in length [5]. Females are typically larger and more brightly colored than their male counterparts [5]. They can differ in color, but bodies typically range from a light tan to a dark brown [4]. Their most distinct feature is the coloration around their eyes. The Wood frog has two black markings that extend back from their eyes, resembling a mask [6]. The underbelly is white and sometimes has small grey marks [4]. This frog has two distinct ridges that run down their back. These ridges are known as Dorsolateral folds [6].

Anatomical diagram of an adult Wood frog.

Range and Habitat

This map shows the geographical range for Lithobates sylvaticus.

Wood frogs have a very large range. They are found in Canada and North America [5]. Their range goes as far south as the Appalachian mountains and as far north as Alaska [6]. They can also be found in smaller populations in Alabama and Idaho [5]. The Wood frog is the only frog that lives in the Artic Circle, this is due to their ability to freeze [5].

Wood frogs typically like both deciduous and coniferous forests [6]. They gravitate towards forests with a closed canopy to keep out sunlight and keep in moisture [2]. This species likes lots of leaf litter and wood debris on the forest floor for shelter [4]. Especially in the winter, Wood frogs can go upland and seek refuge in the leaf litter while they hibernate [3]. When they are not breeding, they can be found in an moist forested areas, ravines, bogs or forested swamps. When spring comes they migrate into forested wetlands or other protected bodies of water to breed [2].

During mating season, these frogs find temporary pools of water of vernal pools [6]. These can be any cut off water sources like streams or ponds, and can even be in ditches. These are preferably free of fish to increase survivability of the offspring [6]. Wood frogs are diurnal and are rarely seen at night but often heard in loud choruses during mating season [5].

Cold Tolerance

Wood frogs are one of the only species of frog to live in the Artic Circle, this is due to their ability to freeze [4]. These frogs "freeze over" in the winter, this serves as hibernation [5]. The freezing process works by releasing large amounts of glucose into their bloodstream, this keeps their body cells from freezing, but not their other bodily fluids [4]. The distribution of liver glycogen enhances the survival of cells, tissues, and organs. This was seen by experimentally adding additional glucose to the Wood frog which increased its tolerance to freezing [1]. This glucose distribution raises the osmotic pressure of the body fluids, which in turn reduces the amount of ice that forms at any given temperature [1]. The Wood frog also creates and antifreeze using their urea [5]. These cryoprotectants keep the water within their cells from freezing because this would indeed kill them [5]. As winter ends the frogs will begin to thaw and begin the breeding process [5].


Diet

As tadpoles, Wood frogs only eat algae and other frog larvae, but as they grown into their adult stages they become omnivores [4]. While inhabiting the forests, they feed on a variety of small invertebrates that they find on the forest floor. With their long tongue they can catch insects including, arachnids, worms, slugs, and snails [5]. The Wood frog is not particular about its diet and will eat just about anything that's the size of its mouth [3]. These frogs are often seen as easy prey, and are eaten by snapping turtles, raccoons, skunks, coyotes, foxes, and birds [5].

Reproduction

Wood frogs will leave their leaf litter refugee after "freezing off" to find a vernal pool for breeding [6]. This process typically begins as early as March and as late as April [4]. The male frogs will make a crocking noise to attract a mate when they are ready, this is typically at night [3]. While the male is on the back of the female they will both simultaneously release their gametes, sperm and egg, into the water [3]. The eggs are now fertilized, and can continue to grow in the water [3]. Each female can lay 1,000 to 3,000 eggs per season [5]. To prevent the eggs from drifting downstream the egg mass attaches itself to nearby vegetation [3]. It takes the eggs about one week until they hatch, once hatched they are in their tadpole stage [3]. This stage can last at least two months, and is likely to be longer if nutrient availability is low [3]. After the two months, the tadpoles have transformed into froglets [3]. These froglets are only about ten centimeters long and it takes two more years until they before adult Wood frogs [3]. After two years, the Wood frog is fully matured it may began to mate, and the process begins again [3]. Wood frogs have a life span of about 3 years [5].



References

[1] Costanzo, Jon P., et al. “Cryoprotectants and Extreme Freeze Tolerance in a Subarctic Population of the Wood Frog.” PLOS ONE, vol. 10, no. 2, Feb. 2015, p. e0117234. PLoS Journals, doi:10.1371/journal.pone.0117234.

[2] Integrated Taxonomic Information System - Report. (n.d.). . https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=775197.

[3] Preston, B. (n.d.). The Biology of the Wood Frog. Nature North. http://www.naturenorth.com/spring/creature/woodfrog/wf2.html.

[4] Wild things in your woods. (n.d.). . Cornell University. https://cpb-us-e1.wpmucdn.com/blogs.cornell.edu/dist/a/7804/files/2018/05/Wood-Frog-23xt0xr-11v8dab.pdf.

[5] Wood frog. (n.d.). . National Wildlife Federation. https://www.nwf.org/educational-resources/wildlife-guide/amphibians/wood-frog#:~:text=Wood%20frogs%20are%20found%20in,lay%20eggs%20in%20vernal%20pools.

[6] Wood Frog. (n.d.). . Virginia Herpetological Society. https://www.virginiaherpetologicalsociety.com/amphibians/frogsandtoads/wood-frog/wood_frog.php.