Hyla cinerea

The American green tree frog (Dryophytes cinereus or Hyla cinerea) is a common arboreal species of New World tree frog belonging to the family Hylidae. This nocturnal insectivore is moderately sized and has a bright green to reddish-brown coloration. When defending territory, the frog either emits aggressive call signals or grapples with intruders. To avoid predation, the frog hides in its aquatic habitat.

DESCRIPTION

• The American green tree frog is of moderate size, characterized by its long legs, streamlined and slender build, and smooth skin.

• This frog typically measures between 3.2 to 6.4 centimeters (approximately 1+1⁄4 to 2+1⁄2 inches) in length.

• The coloration of its dorsum can vary, ranging from the more common bright green to reddish-brown. Such variability in color can sometimes lead to confusion with other frog species. Interestingly, there is evidence suggesting that green tree frogs can undergo color changes in response to their surroundings and temperature.

• The dorsum of these frogs is adorned with small golden spots, and their ventral side exhibits a white to cream coloration. American green tree frogs also feature prominent white lateral stripes.

• In terms of temperature regulation, they are typically ectothermic and heterothermic. On average, the American green tree frog weighs about 3.76 grams, with a range between 2.15 grams and 5.11 grams.

• Female frogs are generally larger than their male counterparts. Larger males often have an advantage in attracting females, either through increased physical strength in competitive encounters or by emitting more pronounced call signals during mating competitions.

REPRODUCTION

• Most American green tree frog females breed once per year, but some have multiple clutches in a single mating season. The average number of eggs in a single clutch was observed to be about 400 for this specific population. Eggs take between 4 and 14 days to hatch, with an average of five days.

• Tadpoles are green with a yellow or white stripe extending from each nostril to the eye and may have mottled tail fins.  American green tree frogs show only the parental investment of mating and egg-laying.

• Breeding is known to be strongly influenced by day length, temperature, and precipitation.

• Mating Calls:

Male American green tree frogs use distinct advertisement calls to attract mates. This helps prevent mating with other frog species when they share breeding areas. After attracting a mate, males engage in amplexus to facilitate fertilization. These frogs are polygynous, aiming to mate with multiple females. Their eggs are typically laid in permanent bodies of water, unlike other frog species that use vernal pools.

• Challenges of Choruses:

When male frogs form choruses, they face intense intraspecific mating competition. They must produce unique, attractive, and audible calls to win over limited females. Challenges include rapidly changing positions within the chorus, exposure to predators, and sexual selection. To adapt, males modify their call features and timing to reduce interference. This selective attention strategy helps them stand out to potential mates.

• Satellite Males:

Some male green tree frogs, called "satellites," remain silent and intercept nearby calls to mate with approaching females. This conserves energy and avoids predation during mate competition. Androgens, which are used for call signal production, decrease in satellite males compared to calling males.

• Eavesdropping and Adaptation:

Male green tree frogs eavesdrop on nearby competitors and adjust mating responses based on call qualities. Females prefer larger males with lower-frequency calls. Large males reduce latency to call and raise call rates when competing with low-frequency callers. Small males reduce latency only when competitors have average call frequencies.

• Interspecific Competition:

American green tree frogs can also compete with other species, like the Cuban tree frog, whose calls are similar. To compete effectively, American green tree frogs modify their calls to be shorter, louder, and more frequent, ensuring better communication and mating success.

HABITAT

American green tree frogs typically inhabit open canopy forests and areas with permanent water bodies abundant in vegetation. They are known to thrive in both natural and human-settled environments. You can commonly find these frogs in habitats such as cypress ponds, water lily prairies, and marshes. They often perch on twigs, low branches, and grasses.