Sunday, October 7, 2012
Life Cycle of a Frog
(photo courtesy of Emile Vandecasteele)
While in some cases, complicated courting behavior occurs before mating, many species of frogs are known for attempting to mate with anything that moves which isn't small enough to eat!
Some frogs leave after this point, but others stick around to watch over the little ones. Some have very unusual ways of caring for their young. You'll learn about some of those later in this tour!.
Life starts right as the central yolk splits in two. It then divides into four, then eight, etc.- until it looks a bit like a rasberry inside a jello cup. Soon, the embryo starts to look more and more like a tadpole, getting longer and moving about in it's egg.
Usually, about 6-21 days (average!) after being fertilized, the egg will hatch. Most eggs are found in calm or static waters, to prevent getting too rumbled about in infancy!
Some frogs, like the Coast foam-nest treefrog, actually mate in treebranches overlooking static bonds and streams. Their egg masses form large cocoon-like foamy masses. The foam sometimes cakes dry in the sun, protecting the inside moisture. When the rain comes along, after developement of 7 to 9 days, the foam drips down, dropping tiny tadpoles into the river or pond below.
After about 4 weeks, the gills start getting grown over by skin, until they eventually disappear. The tadpoles get teeny tiny teeth which help them grate food turning it into soupy oxygenated particles. They have long coiled guts that help them digest as much nutrients from their meadger diets as possible.
By the fourth week, tadpoles can actually be fairly social creatures. Some even interact and school like fish!
The arms will begin to bulge where they will eventually pop out, elbow first.
After about 9 weeks, the tadpole looks more like a teeny frog with a really long tail. It is now well on it's way to being almost fullgrown!
Now these frogs will start the whole process again...finding mates and creating new froggies.