skip to main content

Animals, plants and habitat

Biodiversity in King County, Washington

To offer a suggestion or report an error on the King County Biodiversity website, please contact Jennifer Vanderhoof, senior ecologist.

Biodiversity of Wildlife - Animals and Plants - in King County, Washington State

Tree frog

Check out this series of images showing the entire life history of a tree frog, from egg all the way through metamorphosis to tadpole to adult.

All photos by Jo Wilhelm unless otherwise noted.

1. Pacific Treefrogs lay eggs in clusters of 10-80 eggs typically attached to vegetation in shallow, still water. Each cluster is a soft, irregularly shaped mass that does not hold its shape out of the water. A single female frog lays 20-30 egg clusters in a breeding season. The eggs here are in the early stages of cell division.
tree frog eggs

2. Pacific treefrogs breed primarily in January and February; however, eggs have been found every month from December through September depending on elevation and latitude. The embroyos here have developed a tail bud.
larvae

3. Eggs generally hatch in 2-3 weeks, but this time varies based on water temperature. One dead egg is visible in this picture (the opaque white circle), whereas the other embryos are very developed and are likely close to hatching.
older larvae

4. The larval stage (tadpole stage!) lasts 2-3 months after egg hatching and before transforming into frogs. The tadpoles (larva) feed on small organisms suspended in the water such as algae, diatoms and bacteria, and organic and non-organic detritus. Pacific tree frog tadpoles have eyes set toward the side of the head. If viewed from above the eyes protrude beyond the outline of the head.
tadpole

5.Tadpoles can vary in color from dark brown to olive green sometimes with mottling and with a creamy white underside.
tadpole with legs

6. Transformation into frogs typically takes place from June through August. Also note that Pacific Treefrogs have an eye stripe that extends from the snout and stops at the shoulder.
tree frog with long tail

7. Pacific treefrogs are small to medium-sized frogs -- recently transformed frogs are sometimes less than 10 mm in length, and adults can range in size from 25 to 50 mm.
tree frog with shorter tail

8. Dorsal color is not used in identification because adults are highly variable: their colors range from brown or green to gray, tan, reddish, bronze, or black.
tree frog with very short tail
photo by J. Vanderhoof

9. Pacific treefrogs have expanded toe tips. They are widely distributed extending from British Columbia to Baja California in Mexico and from the Pacific Ocean west to Montana, Idaho, Nevada, and Arizona. They range from sea level to 3550 m elevation.
tree frog in wetland

10. Pacific treefrogs are the most abundant frog in our region and are the most commonly heard calling throughout the day during the peak breeding season. Adults feed on small invertebrates including insects, spiders, isopods, and snails. In contrast, fish, snakes, herons, egrets, raccoons, skunks, river otters, and larger frogs all feed on Pacific treefrogs.
tree frog on a tree

2008 was the Year of the Frog (external link). But just because it's not 2008 any more doesn't mean we've forgotten about them.