Northern Red-Legged Frog

ID: lighter colour strip from upper jaw to shoulder w/ dark eye patch, black freckles, red belly and edge of thighs (Kristiina Ovaska, 2015)

Species: Northern Red-Legged Frog
Status: Special Concern
Key Information:

The Northern Red-legged Frog can be found in well-shaded, cool coastal forests. If you’re searching for one in the late winter or early spring, they’ll most likely be in forested wetlands. If you’re looking for them in the summer, they’ll probably be hiding under a log, trying to stay damp and cool in the summer heat. If you’re looking for them in the fall and early winter, then you could find them hopping along in the middle of the forest. They like to wander far from water when the forest is damp with winter rains. In Canada, their exact population size is undetermined. In the wild, the female will reach sexual maturity at 4 years and in captivity, they have been known to live for as many as 15 years!

From November to April, the females will lay clutches of around 700 to 1500 eggs in shallow, slow-moving, permanent water bodies. She will attach her eggs to aquatic vegetation near the shoreline – such as cattails – and these eggs will hatch in late July or early September. It will then take the tadpoles 7 months to progress into froglets and then eventually reach sexual maturity at 3 or 4 years old.

The Northern Red-legged Frogs future is at a high risk. Frogs have very moist, permeable skin, which can easily absorb toxins from both air and water. They also have very specific habitat requirements that they need in order to lay eggs, grow and live comfortably. This makes them highly susceptible to pollution and changes in their habitat via climate change and habitat loss.

Due to human practices such as deforestation, urban development and agriculture, their habitats have been fragmented or destroyed.  They are also killed on roads and harmed from being exposed to high amounts of herbicides and pesticides. We’ve also introduced invasive species such as the Green Frog, which competes with the Northern Red-legged Frog for habitat, as well as introduced the Bull Frog, which preys on them. The change in climate and the increase in hot, dry summer also puts them at risk as they thrive in cool, damp environments. So, overall, the status of the Northern Red-legged Frog has been determined to be of special concern.

Identification – what to look for:

• Males are 7 cm long, females are 10 cm long
• Brown to reddish-brown
• Smooth, moist skin
• Covered in black freckles
• Head is a darker colour with a lighter strip coming from its upper jaw down to its shoulder
• Translucent, red coloured skin under their thighs
• Golden eyes with large eyelids

Where are they found?

• Their habitat ranges from southwestern B.C. down the coast to Northern California
• Found in cool, coastal forests
• Found in forested wetlands
• Prefer waters with lots of shoreline vegetation
• They breed and lay their eggs in shaded and shallow ponds and/or slow-moving water
• Adults tend to stray far from water bodies in the cool, damp months
• They will tend to take cover under forest floor debris in the hot, dry months

• They’re fast! If you attempt to catch one, they’ll probably out hop you!
• Frogs are considered an “indicator species” as their permeable skin makes them susceptible to climate change and pollution; If the frogs are unhappy and sick, then we know that something is wrong in their habitat
• The population of Northern Red-legged Frogs that reside in the USA is considered to be endangered
• The older a Northern Red-legged Frog gets, the redder it becomes!
• Mature males will call out to females from a metre underwater! They make a low, stuttering call to attract the females during breeding season

Useful Links:

Ministry of Environment: Northern Red-legged Frog
South Coast Conservation Program
University of Michigan: Animal Diversity Web
COSEWIC Status Report (PDF): Northern Red-legged Frog