Hourglass tree frog

The hourglass tree frog (Dendropsophus ebraccatus) is a frog that lives in Mexico, Colombia, Belize and Nicaragua.  Scientists have seen it as high as 1600 meters above sea level.

The adult male frog is 23.63 to 26.75 mm long from nose to rear end and the largest adult female frogs are 36.5 mm long.  Frogs that live high up in the hills are larger than frogs that live low and close to the ocean.  This frog's head is wider than its body.  It has yellow skin and a brown pattern on its back that look like an hourglass. 

Male frogs sing for females after it rains.  The rain creates pools of water that are not there during the dry season.  The males sit on plants high above the pools and sing so the females will come to them.  There are also "sneaker males" who sit between the pools and the singing males so the females will meet them first.

The females lay 180 to 300 eggs at a time.  Most frogs can lay eggs either on land or in water but not both.  However, the hourglass tree frog can lay eggs on both.  If the pool is in the sun, the female frog will lay her eggs on a piece of plant under the surface of the water so that they don't dry out.  If the pool is in the shade, she will lay her eggs near the water so that the tadpoles fall into it after they hatch.  For example, she may lay her eggs on a leaf on a branch hanging over the water.  If she lays eggs in the water, fish might eat them.  If she lays eggs on a leaf, wasps, ants or spiders might eat them.

The tadpoles can be 6.72 to 7.47 mm long when they first hatch and they can grow to 2.9 cm.  They eat algae and hide in underwater plants.

The nematode worm parasite Cosmocerca parva can infect this frog.

This frog does not get very sick from the chytridiomycosis fungal disease the way many other frogs do.  Scientists found that the microbiota of hourglass tree frogs, which is all the bacteria and other microorganisms that live on and in the frog's body, is different from the microbiota of other frogs.  Scientists think this might protect the hourglass tree frog from chytridiomycosis but they are not sure.

Scientists and students use the hourglass tree frog as a test animal because it is not endangered and because it can lay eggs on land or in water.  Humans also keep these frogs as pets.

References

Category:Frogs of South America