Tadpoles
Bullfrog tadpoles hatch from their jelly envelopes in just a few days in late July or early August. They will then spend anywhere from two to possibly four years before they transform, or metamorphose, into frogs. They seem to have a longer larval stage in nutrient rich (eutrophic) lakes than in nutrient poor (oligotrophic) lakes.
In the sun-warmed shallows of many local lakes and ponds bullfrog tadpoles gather and crowd to such an extent that the water boils as they scatter upon your approach. Though quick to flee from danger, the tadpoles are nevertheless armed with noxious chemicals in their skins that predators seem to find quite unpalatable. Consequently, with little mortality to predation, their numbers increase every rapidly.
The tadpoles are vegetarian and feed ravenously. As their densities increase they tend to monopolize the primary production in lakes and ponds by devouring filamentous algae and leafy aquatic vegetation and converting it into bullfrog tissue. This is not good for sustaining species diversity locally because bullfrog tadpoles can competitively exclude other species who also require vegetation - particularly in nutrient poor lakes.
