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Rana pipiens, Northern leopard frog

Page history last edited by PBworks 11 years, 10 months ago

Rana pipiens

The Northern Leopard Frog


Picture by Gary Nafis http://www.californiaherps.com/frogs/images/rpipiens04.jpg




Kingdom: Animalia

Phylum: Chordata

Superclass: Tetrapoda

Class: Amphibia

Subclass: Lissamphibia

Order: Anura

Suborder: Neobatrachia

Family: Ranidae

Genus: Rana

Species: pipiens


Key Characteristics

A green or brownish frog with oval or round dark spots on its back with a white or cream underside. This true frog has pale and continuous dorsolateral folds from each eye down the back. In the young the spots may be reduced or completely absent. During the breeding season the males have a swollen, darkened thumb base and loose skin between the jaw and shoulder.


The tadpoles are dark brown or olive to gray on top, and often have fine gold spots. The underside of the tadpoles are usually cream to whitish with very weak pigmentation. It is common to be able to see the intestines through the skin on the belly. 1 Tadpole development usually takes about 70 to 110 days, depending on conditions. 2


Tadpole and mouthparts http://fisc.er.usgs.gov/c1258_Dodd/html/tadpoles.html




As the map below shows, the northern leopard frog can be found all across the North American continent. The distribution of this amphibian stretches all the way up into the northern most parts of Canada, and yet extends down to the border of New Mexico and Mexico. The northern leopard frog is also found on the eastern coast of the continent and almost reaches the western coast.

Distribution of rana pipiens across US http://biology.mcgill.ca/undergra/c465a/biodiver/2001/northern-leopard-frog/northern-leopard-frog.htm


Specifically to Idaho, the distribution of the northern leopard frog is primarily along the Snake River Basin. There is a small area at the very top of the state where rana pipiens are located.

Distribution in Idaho http://imnh.isu.edu/digitalatlas/bio/amph/anurans/rapi/Rapi.htm





The northern leopard frog can be found in a variety of places including grassland, brushland, woodland, and forest ranging into high mountains. It can often be found near springs, slow-flowing streams, marshes, bogs, ponds, canals, and reservoirs. Usually when found in these areas there is permanent water with grass, cattails, or other aquatic vegetation. They are well adapted to extreme cold, and can be found at high elevations. 1




Leopard frogs feed on a variety of invertebrates such as crickets, wax worms, fly larvae, and earthworms. These frogs hibernate through the cold winter months. 3 Male leopard frogs make a short snore-like call from the water during the spring and summer months. These snore-like sounds may be interspersed with grunting sounds as well.They are most active during the day when they are foraging, and they migrate to breeding ponds in the spring. Leopard frogs do not usually set up territories, except during the breeding season. 4




During reproduction the male holds the female using his specialized thumbs, then fertilize the eggs as they come out of her body. During this process the female can lay anywhere from 300 to 6,500 eggs. These eggs are usually in two or three envelopes and attached to vegetation in quite waters. 1


Scientific Study


Melvin Spiegel and David L. Frankel. "Role of Enzyme Induction in Embryonic Development." Science Vol. 133 No. 3448. (1961): p 275


Spiegel and Frankel set out to measure tryptophan pyrrolase activity in the embryos of Rana pipiens. Their measurements did not reveal significant amounts of constitutive enzyme, and all their attempts to induce enzyme formation in embryos by culture in tryptophan solution or in ovarian eggs by injection of tryptophan into the mature female failed.


Before the gastrulation phase of development in embryos .dissociated into cell cultures and incubated in l-tryptophan, enzyme activity was detected, but enzyme activity was not detected in the intact embryo just before hatcing. The most important observation was that before gastrulation began populations of presumptive endoderm cells demonstrated enzyme activity after tryptophan incubation, but after gastrulation was complete, enzyme activity could be induced only in the cultures that contained presumptive gut cells. This led them to the hypothesis that tryptophan pyrrolase activity could be induced in cells lacking constitutive enzyme.


This experiment was carried out by cutting the embryos in halves and quarters to allow penetration of the substrate. Then the jelly and vitelline membrane were removed from Rana pipiens eggs. Intact embryos, halves, and quarters were incubated for 12 hours in either Holtfreter's solution or the Holfreter's solution containing 0.02M L-tryptophan. Cut embryos remained alive, and after five washings with Holtfreter's solution, tryptophan pyrrolase activity was measured. The end results showed no constitutive enzyme present in either the blastula, late gastrula, or early neurula stages. Thus, the incubation in L-tryptophan failed to induce enzyme activity in these stages. 5




1 Robert C. Stebbins (2003). Western Reptiles and Amphibians. 3rd ed. Singapore: Houghton Mifflin. 234-235, 446, 460.


2 Answers.com. http://www.answers.com/topic/northern-leopard-frog


3 Lianne McLeod. "Leopard Frogs." Keeping Northern Leopard Frogs as Pets 1998. About.com:Exotic Pets. http://exoticpets.about.com/cs/frogsandtoads/a/leopardfrogs.htm.


4 Harding, J. (1997). Amphibians and Reptiles of the Great Lakes Region. Ann Arbor, Michigan: The University of Michigan Press. http://animaldiversity.ummz.umich.edu/site/accounts/information/Rana_pipiens.html


5 Melvin Spiegel and David L. Frankel. "Role of Enzyme Induction in Embryonic Development." Science Vol. 133 No. 3448. (1961): p 275



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