EducationVERNAL POOL
INFORMATION


Descriptions Descriptions
Pool Types Pool Types

Wood Frogs

The wood frog (1), Rana sylvatica, is a small (about 2") frog of moist woodlands which has a range of most of northern North America. As the name implies, this frog is not an animal of ponds and streams but one which spends it life in the woodlands and vegetated wetlands of our region. In early spring, shortly after thawing from it's winter dormancy, the wood frog hops it's way to temporary wetlands for breeding. The males set up a raucous quacking chorus which can be heard for a few weeks when the air temperature is above the high 40's.


Obligate species
Fairy shrimp Fairy Shrimp
Wood frogs Wood Frogs
Mole salamanders Mole
Salamanders

After mating (2) and egg laying, the wood frogs leave the vernal pools to spend the rest of the year in the adjacent uplands. The egg masses of a few hundred eggs each are often deposited in communal clusters (3) of hundreds of masses. The gelatin covering, the size of the communal cluster, and exposure to the sun all help the eggs to be warmer than the surrounding water and they develop quickly. By mid to late April, small black wood frog tadpoles (4) are abundant in vernal pools. As they feed on the leaves and algae of the pool, they grow quickly and become a green-brown color. By June, the tadpoles will have developed legs and be absorbing their tail (5) in preparation for leaving the pool.

In years when the vernal pool dries before the development of the tadpole is complete, thousands of tadpoles flop about in the muck and become food for numerous birds, mammals, reptiles and insects as they dry and die. Those frogs which complete development (6) leave the pool as a miniature version of the adult frog and venture into the uplands to spend their life searching for insects and other invertebrates to eat.

A tape of a wood frog chorus or photographs similar to #2-6 below would be suitable evidence of wood frogs breeding in a vernal pool.

1. Females laden with eggs.
wood frogs mating
2. Adults in amplexus.
wood frog egg masses
3. Communal egg masses.
wood frog tadpoles
4. Wood frog tadpoles.
wood frog tadpole with tail and legs
5. Mature tadpole with legs and tail.
emergent wood frog with tail remnant
6. Emergent frog with tail remnant.

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