April 26, 2011
This photograph, taken in the wild at night, is of a Yellow Cricket Tree Frog (Dendropsophus microcephalus) in the middle of his mating call.
These tiny frogs can be found throughout most of Central America, and some South American countries. It lives on the edges of the rainforest, mostly in marshy areas, ponds, and other pools of water.
This species of frog experiences metachrosis (meh-tah-CROW-sis, which means "color change"). During the night, its back is a light yellow color with various brown or tan markings. During the day, it darkens to a light brown with darker brown or red markings. We can tell that this is a photograph of a breeding male, because of his yellow vocal sac (the balloon-like bulge under his chin).
During the mating season, the male frogs gather in large groups of thousands of frogs around the breeding areas and call out from grasses at the edge of water. When they really get going, humans sometimes think the quick "creek-eek-eek-eek" call is being made by crickets. These frogs work hard when they are looking for a mate, producing between 200 to 380 notes per minute at their peak! Even though there are thousands of them making so many short noises, scientists have found that each male is careful to avoid having his calls overlap with others, because he wants to stand out from the other males in the group.
If you want to hear the sound of the calls of the yellow tree frog (and other frogs at well), click on this link. There are seven different frog calls captured in this video, which is a little dark because it was shot in the wild, at night. This frog is the last one on the clip (about 2½ minutes in).
Photo: Brian Gratwicke
Video: Nick Sly
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Posted by: Seymour Simon
