Frog of the Week

California Red-legged Frog (Rana draytonii)

California Red-legged Frog
photo by Chris Brown

Common Name: California Red-legged Frog
Scientific Name: Rana draytonii
Family: Ranidae – True Frog family
Location: United States and Mexico
US Location: California
Size: 1.75 – 5.25 (4.4 – 13.3 cm)

The California Red-legged Frog is found along the coast of Baja California and California. These frogs spent most of their time in or near ponds, lakes, streams, or swamps. They are diurnal, meaning they are active during the day. The frogs are one of the largest native frogs native to the western US. Originally, they were considered a subspecies of the Northern Red-legged Frog (Rana aurora) but were split into their own species

The breeding season happens between late November to April. Reproduction for the frog is pretty standard. At the beginning, the males call from shallow bodies of water. Once a female selects a mate, the male grasps her from the behind in the amplexus position. Then, the female lays her eggs and the males fertilize them. In fact, the female lays between 300 – 4000 eggs. Additionally, neither parent provides any care for the offspring. The eggs hatch in 4 weeks. Then, the tadpoles take 4 to 7 months to complete their metamorphosis.

photo by William Flaxington

California Red-legged Frog Conservation

The California Red-legged Frog is listed as a federally threatened species and the International Union for the Conservation of Nature (IUCN) Red List classifies them as Vulnerable to Extinction. Much of its range has been lost to land development. Researchers estimate that they have lost 70% of their historic range. Additionally, invasive species, such as the American Bullfrog, and heavy use of pesticides haven’t helped the frog either. The state of California named the California Red legged Frog as their state amphibian to help inform the public of the conservation concerns. The San Francisco Zoo with the help of the USFWS have begun breeding and raising the frogs in captivity. They started to release some of these frogs and tadpoles into the wild to help repopulate the species.

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