Print | Bookmark

Wood Frog

Rana sylvatica LeConte

Wood Frogs are brown or tan-coloured. A dark brown mask on the sides of the head has earned them the nickname "robber frog", although the mask is not obvious in breeding males. Some females in red sandstone areas may become red coloured.

Wood Frogs and Spring Peepers are the first amphibians to emerge in spring. The males, which usually far outnumber the females, congregate on the surface in vegetated areas of ponds. The call is a hoarse racket like a number of ducks quacking in a distant pond. Males are vocal all night long, if temperatures are above freezing. At night, you may see pairs of frogs in amplexus, with the smaller male gripping the female tightly behind her forearms. Breeding is over by May in most regions. Females lay fist-sized jelly masses of about 1000 eggs. The tadpoles develop rapidly and transform during July and August.

Except for breeding, Wood Frogs live in damp deciduous or mixed woods. They begin feeding after the spawning season. They eat a variety of insects and other small invertebrates, especially spiders, beetles, bugs, moth larvae, slugs and snails.

Additional Facts and Details

The family Ranidae of typical frogs consists of 45 genera and 586 species and is distributed nearly worldwide.

The genus Rana is represented in the Maritimes by 6 species in New Brunswick and Nova Scotia, while 3 occur on Prince Edward Island.

The toes on the front legs are unwebbed.

Breeding males can be told from females by the swollen base of the thumbs on the forelegs. This is related to the tight holding they do during amplexus.

Some females in the red sandstone, shale and conglomerate areas of the northern mainland are reddish-brown, washed with copper-green on the groin.

Size: body length of 230 males ranged from 3.8 to 5.3 mm; of 53 females, 4.8 to 6.0 mm.

The dorsolateral folds are prominent and extend the length of the trunk.

Distribution in North America: Wood Frogs occur farther north than any other amphibian or reptile, as far as the treeline from Labrador to the Yukon. Not found in the short-grass prairie of Saskatchewan and Alberta or in central and southern British Columbia. Extends north of the Arctic Circle in the MacKenzie River Valley. In the United States, from Maine west to North Dakota and south to the Appalachians.

In Nova Scotia, the Wood Frog is widely distributed on the mainland and Cape Breton Island.

Wood Frogs have been successfully introduced into Newfoundland.

Earliest spring record is March 22, 1983, one adult crossing a wet highway at the Forties Settlement, Lunenburg County.

On the night of May 13, 1975, in a roadside pond in Kingsville, Inverness County, more than 20 males were vocal and moving around the surface. The vocal sacs of some of the males were so inflated they had great difficulty diving underwater.

In a pond near the railroad at Tatamagouche, Colchester County, May 2, 1978, 53 Wood Frog egg masses were observed. As many as eight egg masses were fixed to a single cattail stem.

Latest fall record is November 5, 1982, when 3 adults were seen on a wet highway at the Forties.