Amphibians of Boulder County:
Springtime brings the frogs and toads out of hibernation. We hear them croaking near vernal ponds. They must have clean, calm water to complete their life cycle. All frogs absorb water through their skin from wet grass, damp ground or water. If they are out in dry air too long they dehydrate and die. Since they are cold-blooded they need warm temperatures to thrive.
Our Western chorus frogs are tiny, only 1¼ inch for the biggest females (males are smaller). Furtive and nocturnal by nature, they are very hard to see.
The males inflate their air sacs under their chins to make a sound like running a thumbnail down a comb. Females hear and are attracted up to a half mile away.
Chorus frogs manage to survive the winter by sheltering under logs, or in leaf piles and actually freeze solid. Their heart stops and they stop breathing, but there is a sort of glycol-like substance in their blood that keeps crystals from forming and bursting the cell walls. Since many of the spring pools are ephemeral (short lived) they get right to the mating business once they wake up. Females lay 500 to 1500 gelatinous eggs in clusters of 20 to 200 which the male clinging to her back, fertilizes as she lays.
Depending on how cold the water is, they hatch into tadpoles (aka.polliwogs) after a few weeks (longer if the water is really cold). If they all survived we’d be knee deep in frogs. However, tadpoles are at the bottom of the food chain…the mice of the aquatic world. Snakes, ducks, turtles, salamanders, fish, and larger tadpoles love to eat them. Dragonfly and other insect larvae are particularly fond of taddies.
Tadpoles that manage to continue the metamorphosis process will absorb their tails and grow legs. When this process is complete they hop out of the pond as tiny froglets.
Now new predators have a go at reducing the numbers: raccoons, herons, hawks, corvids (crows and relatives), and bigger snakes.
Adult frogs will gulp anything they can fit in their mouths. They whip out their sticky tongues to snag flying insects, ants, beetles, spiders, slugs, snails and worms. If the prey is large they can push their eyeballs down towards their mouths in order to force the food down their throats.
Our native frogs can survive as long as 9 years when conditions are favorable. But invasive bullfrogs, water pollution, disease, and loss of wetlands have put frogs in serious jeopardy worldwide.
Toads are relatives of frogs. Our Great Plains toads spend a lot more time away from water as adults. They like grassland habitat with loose soil for easy digging. Their skin isn’t as porous as frogs so they don’t dehydrate as easily. However, they need water to breed as their reproductive cycle is the same as frogs. They will breed throughout the summer, emerging from their burrows after heavy rains. The male Great Plains toad makes a kind of screaming noise with its air sac to attract the lovely ladies. They winter in their burrows.
Th-th-that’s all for now folks, until inspiration strikes again.