Wood Frog (Rana sylvatica)
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Introduction
The Wood Frog is Canada’s most widespread amphibian and is an Obligate Vernal Pool Species. Wood frogs breed in vernal pools, and adults forge in moist forests and swamps.
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| Description: |
- Brown, tan to copper
- Dark bar behind the eye, with dark line from nostril to front of eye
- White upper lip
- Folds of skin along both side of back
- Hind legs often with bands
- White belly
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| Size: |
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| Distribution: |
- Most widely distributed amphibian in Canada,
- Occurs farther north than any other North American amphibian species. Found in the tundra. Can tolerate freezing temperatures.
- All of Ontario
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| Abundance: |
- Common where habitat suitable
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| Non- Breeding Habitat: |
- Moist forests and swamps
- Hibernate beneath soil, leaf litter, and decaying logs
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| Breeding Habitat: |
- Vernal pools and ephemeral wetlands with vegetation
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| Timing of Breeding: |
- Late March to late-April
- Breeds as soon as the ice open in the spring
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| Call: |
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| Egg masses: |
- Female deposits between 500 and 3000 eggs in a lose round gelatinous masses
- Attach egg masses to vegetation below waters surface
Communal egg laying
- Egg masses clear to opaque, but may turn green with algae
- Incubation period is dependant on temperature (4 days to 4 weeks)
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| Larvae: |
- 3-4 cm long, plump with short, high tail fin
- Brown or olive, with black or gold specks
- Transparent belly with coiled intestine visible
- Usually transform within two months. Must transform before water dries up.
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| Migration: |
- Adults to breeding vernal pools and wetlands in late March to late April
- Breeding migration usually takes place on the first warm rainy nights of early spring.
- Juvenile migration late April to July
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| Larvae Food: |
- Algae, diatoms, and decaying plant and animal matter
- Can be carnivorous, feeding on eggs and larvae of other amphibians
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| Larvae Predation: |
- Predaceous Diving Beetles, Giant Water Bugs, and the larvae of Ambystoma salamanders
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| Juvenile Food: |
- Higher percentage of aquatic invertebrates
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| Adult Food: |
- Terrestrial invertebrates; including beetles, crickets, caterpillars, spiders, earthworms, slugs, snails, and mosquitoes
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| Adult Predation: |
- Larger frogs, Garter Snakes, Ribbon Snakes, Northern Watersnakes, herons, Raccoons, Skunks, Minks, leeches, aquatic insects and their larvae, and Eastern Newts
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| Conservation Concerns: |
- Deforestation, Wetland and vernal pool filling and drainage have resulted in the extirpation of Wood Frogs in portions of southwestern Ontario.
- Fatal encounters with automobiles during migration
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References:
Environment Canada, Canadian Nature Federation, EMAN, and University of Guelph. FrogWatch Ontario Website. http://www.naturewatch.ca/english/frogwatch/on/intro.html. Visited January 17, 2004 at 1:00 pm
Harding, J.H., 1997. Amphibians and Reptiles of the Great Lakes Region. The University of Michigan Press. Ann Arbor
MacCulloch, R.D., 2002. The ROM Field Guide to the Amphibians and Reptiles of Ontario. Royal Ontario Museum and McClelland & Stewart Ltd. Toronto.
Toronto Zoo – Adopt-A-Pond Program. Guide to the Amphibian and Reptiles of Ontario – Wood Frog. http://www.torontozoo.com/adoptapond/guide/woodfrog.html. Visited January 17, 2004 at 1:00 pm
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