Northern leopard frog

From Wikipedia, the free encyclopedia

Northern leopard frog
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Ranidae
Genus: Lithobates
L. pipiens
Binomial name
Lithobates pipiens
(Schreber, 1782)
Range of L. pipiens

Lithobates pipiens[1][2][3][4] formerly Rana pipiens,[5][6] 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.


Young northern leopard frog

The northern leopard frog is a fairly large species of frog, reaching about 11 cm (4.3 in) in snout-to-vent length. It varies from green to brown in dorsal color, with large, dark, circular spots on its back, sides, and legs.[7] Each spot is normally bordered by a lighter ring. A pair of dorsolateral folds starting from the back of the eye runs parallel to each other down the back. These dorsolateral folds are often lighter or occasionally pinkish in colour. Also, a pale stripe runs from the nostril, under the eye and tympanum, terminating at the shoulder. The ventral surface is white or pale green. The iris is golden and toes are webbed.

Tadpoles are dark brown or grey, with light blotches on the underside. The tail is pale tan.

Color variations[edit]

Two burnsi morphs, a green morph, and a brown morph of the northern leopard frog
Brown morph northern leopard frog in a wood chip pile in Iowa

The northern leopard frog has several different color variations, with the most common two being the green and the brown morphs, with another morph known as the burnsi morph. Individuals with the burnsi morph coloration lack spots on their backs, but may or may not retain them on their legs. They can be bright green or brown and have yellow dorsal folds.[8] Albinism also appears in this species, but is very rare.

Ecology and behavior[edit]

Near Welland Canal, Ontario

Northern leopard frogs have a wide range of habitats. They are found in permanent ponds, swamps, marshes, and slow-moving streams throughout forest, open, and urban areas.[9] They normally inhabit water bodies with abundant aquatic vegetation. In the summer, they often abandon ponds and move to grassy areas and lawns. They are well adapted to cold and can be found above 3,000 m (9,800 ft) above mean sea level. Males make a short, snore-like call from water during spring and summer. The northern leopard frog breeds in the spring (March–June). Up to 6500 eggs are laid in water, and tadpoles complete development within the breeding pond. Tadpoles are light brown with black spots, and development takes 70–110 days, depending on conditions. Metamorph frogs are 2–3 cm (0.79–1.18 in) long and resemble the adult.

This species was once quite common through parts of western Canada and the United States until declines started occurring during the 1970s. Although the definitive cause of this decline is unknown, habitat loss and fragmentation, environmental contaminants, introduced fish, drought, and disease have been proposed as mechanisms of decline and are likely preventing species' recovery in many areas.[7] Many populations of northern leopard frogs have not yet recovered from these declines.

Northern leopard frogs are preyed upon by many different animals, such as snakes, raccoons, other frogs, and even humans. They do not produce distasteful skin secretions and rely on speed to evade predation.

They eat a wide variety of animals, including crickets, flies, worms, and smaller frogs. Using their large mouths, they can even swallow birds and garter snakes. In one case, a bat was recorded as prey of this frog.[10] This species is similar to the pickerel frog (Lithobates palustris) and the southern leopard frog (Lithobates sphenocephalus).



The northern leopard frog produces specific ribonucleases to its oocytes. Those enzymes are potential drugs for cancer. One such molecule, called ranpirnase (onconase), is in clinical trials as a treatment for pleural mesothelioma and lung tumors. Another, amphinase, has been described as a potential treatment for brain tumors.[11]


The northern leopard frog has been a preferred species for making discoveries about basic properties of neurons since the 1950s. The neuromuscular junction of the sciatic nerve fibers of the sartorius muscle of this frog has been the source of initial data about the nervous system.[12][13][14][15][16][17][18]

Muscle physiology and biomechanics[edit]

The northern leopard frog is a popular species for in vitro experiments in muscle physiology and biomechanics due to the ease of accessibility for investigators in its native range and the ability of the sartorius muscle to stay alive in vitro for several hours. Furthermore, the reliance of the frog on two major modes of locomotion (jumping and swimming) allows for understanding how muscle properties contribute to organismal performance in each of these modes.


Northern leopard frogs occur from Great Slave Lake and Hudson Bay, Canada, south to Kentucky and New Mexico, USA.[19][20] It is also found in Panama, where it is endemic to the central cordillera and western Pacific lowlands, although this is most likely an undescribed species.[1] They occupy grasslands, lakeshores, and marshes.

See also[edit]


  1. ^ a b c IUCN SSC Amphibian Specialist Group (2022). "Lithobates pipiens". IUCN Red List of Threatened Species. 2022: e.T79079800A3072377. Retrieved 14 December 2022.
  2. ^ Frost, Darrel (2011). "American Museum of Natural History: Amphibian Species of the World 5.5, an Online Reference". Herpetology. The American Museum of Natural History. Retrieved 2013-02-17.
  3. ^ Frost, D.-R.; et al. (2009). "Response to the Point Of View of Gregory B. Pauly, David M. Hillis, and David C. Cannatella, by the Anuran Subcommittee of the SSRA/HL/ASIH Scientific and Standard English Names List". Herpetologica. 65 (2): 136–153. doi:10.1655/09-009R1.1. S2CID 55147982.
  4. ^ Integrated Taxonomic Information System [Internet] 2012. Lithobates pipiens [updated 2012 Sept; cited 2012 Dec 26] Available from:
  5. ^ Hillis & Wilcox (2005), Hillis (2007), Stuart (2008), Pauly et al. (2009), AmphibiaWeb (2016)
  6. ^ Yuan, Z.-Y.; et al. (2016). "Spatiotemporal diversification of the true frogs (genus Rana): A historical framework for a widely studied group of model organisms". Systematic Biology. 65 (5): 824–42. doi:10.1093/sysbio/syw055. PMID 27288482.
  7. ^ a b Northern Leopard Frog Rana pipiens, National Geographic. Retrieved 2015-03-28
  8. ^ "Northern Leopard Frog Rana pipens". HerpNet. Retrieved 2013-10-30.
  9. ^ Northern Leopard Frog (Lithobates pipiens), Nevada Fish and Wildlife Office. Retrieved 2015-03-28.
  10. ^ Mikula, P (2015). "Fish and amphibians as bat predators". European Journal of Ecology. 1 (1): 71–80. doi:10.1515/eje-2015-0010.
  11. ^ Frog molecule could provide drug treatment for brain tumors
  12. ^ Fatt, P; Katz, B (1952). "Spontaneous subthreshold activity at motor nerve endings". The Journal of Physiology. 117 (1): 109–28. doi:10.1113/jphysiol.1952.sp004735. PMC 1392564. PMID 14946732.
  13. ^ Del Castillo, J; Katz, B (1954). "Quantal components of the end-plate potential". The Journal of Physiology. 124 (3): 560–73. doi:10.1113/jphysiol.1954.sp005129. PMC 1366292. PMID 13175199.
  14. ^ Lettvin, J.Y.; Maturana, H.R.; McCulloch, W.S.; Pitts, W.H. (1959). "What the Frog's Eye Tells the Frog's Brain". Proceedings of the IRE. 47 (11): 1940–51. doi:10.1109/JRPROC.1959.287207. S2CID 8739509.
  15. ^ Katz, B; Miledi, R (1965). "The Measurement of Synaptic Delay, and the Time Course of Acetylcholine Release at the Neuromuscular Junction". Proceedings of the Royal Society of London. Series B. 161 (985): 483–95. Bibcode:1965RSPSB.161..483K. doi:10.1098/rspb.1965.0016. PMID 14278409. S2CID 8663912.
  16. ^ Kuffler, SW; Yoshikami, D (1975). "The number of transmitter molecules in a quantum: An estimate from iontophoretic application of acetylcholine at the neuromuscular synapse". The Journal of Physiology. 251 (2): 465–82. doi:10.1113/jphysiol.1975.sp011103. PMC 1348438. PMID 171380.
  17. ^ Hille, B (1967). "The selective inhibition of delayed potassium currents in nerve by tetraethylammonium ion". The Journal of General Physiology. 50 (5): 1287–302. doi:10.1085/jgp.50.5.1287. PMC 2225709. PMID 6033586.
  18. ^ Anderson, CR; Stevens, CF (1973). "Voltage clamp analysis of acetylcholine produced end-plate current fluctuations at frog neuromuscular junction". The Journal of Physiology. 235 (3): 655–91. doi:10.1113/jphysiol.1973.sp010410. PMC 1350786. PMID 4543940.
  19. ^ Stebbins, R.C. (1985). A Field Guide to Western Reptiles and Amphibians. Second Edition. Houghton Mifflin Company, Boston, Massachusetts.
  20. ^ Conant, R. and Collins, J.T. (1991). A Field Guide to Reptiles and Amphibians: Eastern and Central North America. Third Edition. Houghton Mifflin Company, Boston, Massachusetts.

Further reading[edit]

External links[edit]