So this week’s Creature Feature is the Common Gray Tree Frog (Hyla versicolor) and the Cope’s Gray Tree Frog( Hyla chrysoscelis). I am doing two because these two frogs are identical in the field and can only be positively identified in the lab, by looking at the number of chromosomes. Common Gray Tree Frogs have twice as many chromosomes as the Cope’s Gray Tree Frog. If you live in an area where only one of these frogs exist, then identification will be easy for you. If however, you live where they both exist, telling the difference will be challenging.
1. Gray tree frogs are capable of rapid color changes, depending on their surroundings. They can be green, gray or various shades of these colors.
2. These are pretty small frogs, only 2 3/8 inches long! Full grown they can sit on the top of your finger! They have sticky toe pads and are excellent climbers, including scaling perfectly smooth glass windows.
3. The most amazing thing about these tiny frogs is their ability to freeze solid in the winter and then thaw out in the spring. These frogs have large amounts of an anti-freeze like material in their bodies called glycerol. In the winter their heart beat and breathing stops! but they can thaw out in the spring because the glycerol prevents the liquid inside their cells from freezing. They spend the winter under leaves, in rocks, crevices or under dead trees.
4. These frogs produce a toxic chemical in their skin that may irritate a predator‘s (or person handling one) eyes, nose, lips or open wounds.
5. Like other frogs, gray tree frogs lay their eggs in a body of freshwater. In April or May, females lay as many as 2000 eggs, laid in masses of 30-40. Tadpoles transform into frogs in 6-9 weeks depending on the temperature of the water. The warmer it is, the faster they will transform.
6. Gray tree frogs eat insects and small invertebrates, including moths, crickets, ants, beetles, flies and bugs.
7. These frogs are nocturnal and can often be heard calling on rainy nights throughout the summer. Males call from April -August. On rainy days during this time, it is not unusual to hear them in the day as well as at night.
8. Young frogs are bright green. They will reach maturity within 2 years.
9. The common gray tree frog has a faster trill than the cope’s gray tree frog. It is also said to be more musical and bird-like. Click below to hear the common gray tree frog, or below that to hear the cope’s gray tree frog. Both sounds are from Lang Elliot at Nature Sounds Studio.
10. Tadpoles of gray tree frogs may have a red-tipped tail.