Complete Guide To The Green Frog

Green Frog Notes

• Green Frogs live close to shallow water and are widespread across North Carolina.
  • Look for them in and near springs, swamps, streams, ponds, and lakes, as well as near fallen trees in very moist areas.
• In my experience, Green Frogs are much less wary than other common frog species, especially the Bullfrog. They hold their positions for a surprisingly long time if approached slowly and calmly, although they hop into water and disappear rapidly in response to sudden movement or noise.
• Green Frogs breed throughout the summer, from about March to August (Behler and King 2020).
• Green Frogs may change sex, and this transition may be a normal part of their biology.
  • A research study by Max Lambert and co-authors studied 464 adult Green Frogs and found evidence of sex reversal in both directions, including:
    • 8.5% of genetic females that showed male traits
    • 3% of genetic males that showed female traits (Lambert et al. 2019)
• Male Green Frogs establish and defend territories that can range in size between three and twenty feet in diameter.
  • Male Green Frog advertise for mates by sitting upright with their heads and bodies clear of the water and giving calls that sound like a plucked banjo string.
  • When a non-resident male invades another male’s territory, the resident male gives a single warning call that sounds like their mating call, only louder and more abrupt.
  • If the invader fails to retreat, the males will fight. Green Frogs make long, soft growling sounds right before, and during, wrestling matches for dominance (Tyning 1990).
• Both male and female Green Frogs give a special call that sounds like a series of chirps, but they give this call in different scenarios and, presumably, for different reasons.
  • Females chirp either when they have already deposited their eggs or when they don’t have eggs to lay.
  • Males chirp when they are in the midst of losing a dominance wrestling match with a larger, more aggressive male (Tyning 1990).
  • The sound seems to represent a “release call”—a signal to other frogs to let them go, or leave them alone.
• Female Green Frogs lay around 3000 to 5000 eggs at a time. The eggs float in large mats or are draped over submerged vegetation and hatch in three to seven days.
  • Tadpoles that hatch early in the summer transform into adult frogs by the fall.
  • Those that hatch later in the summer overwinter in their ponds and transform the following spring.
• Green Frogs eat a wide variety of arthropods, like insects and spiders, molluscs, like snails and slugs, and aquatic crustacheans.
• They are, in turn, eaten by a wide variety of predators.
  • Predators of tadpole Green Frogs include predatory fish, like Eastern Mosquitofish (Gambusia holbrooki) and Pirate Perch (Aphredoderus sayanus), Bullfrog tadpoles, and dragonfly larvae.
    • Green Frog tadpoles reduce their activity when they sense chemical cues in the water that indicate dragonfly larvae, such as Common Green Darners (Anax junius) or Comet Darners (Anax longipes), recently fed on other Green Frog tadpoles (Fraker 2008, https://doi.org/10.1007/s00265-008-0549-9).
  • Predators of adult Green Frogs include:
    • Birds like Great Blue Herons (Ardea herodias), Great Egrets (Ardea alba), and American Bitterns (Botaurus lentiginosus).
    • Reptiles like Snapping Turtles (Chelydra serpentina) and Northern Water Snakes (Nerodia sipedon).
    • Mammals, like Raccoons (Procyon lotor), Northern River Otters (Lutra canadensis) and Minks (Mustela vison).
    • Bullfrogs