Sunday, April 25, 2010

Strawberry Poisonous Dart Frogs, By Sharon Powell


Assuming the colorful bundle of beauty pictured above is harmless to predators could be a fatal mistake, even for humans. The Strawberry Dart Frog is one of the most deadly amphibians combing the rain forests today. Although the tiny frog may be difficult to find, they are magnificent creatures and can be seen “leaping” in and around tight places throughout many parts of Central and South America.

There are over 100 different species of poisonous frogs ranging in size from 3/4"inches up to six inches long. The smallest of all dart frogs looks much like the colorful Strawberry species, but is smaller by nature. The Buzzer is only 3/4" inches long and no bigger than the size of a thumbnail, but like all dart frogs, the Buzzer packs a powerful punch if trying to catch one without protection.

Powerful Predator
Most all dart frogs are bright in color and appear harmless. Although the Amphibian displays a rainbow of beauty, the frog is equipped with poisonous glands located on the outer layers of skin. These glands contain enough poison to kill twenty men. If a jungle snake should happen to digest the dart frog, the snake becomes paralyzed and the heart muscle will stop within minutes, causing death in the reptile. If a predator should choke on the tiny frog, they will either die, or remember the terrible taste and never bother them again.

The poisonous substance contained within the gland is commonly used to relieve pain, or prevent heart attacks within humans. Scientists and wildlife biologist search the rainforests for the dart frog in order to remove the chemical. Once the poison is expelled, the frogs are released back into the jungle and will later reproduce the toxin as a means of defense.

Habitat
Long ago, hunters learned how to extract the poison by rubbing the frog’s glands with the tip of their darts. The darts were later used in blowpipes as ammunition. The blowpipe makes no sound when used and therefore the hunted animal will not become frightened away. The silent ways of hunting have proven beneficial to the hunter and is still a common practice used today.

In order the dart frog continue to survive, their skin must remain moist, or they will dehydrate and die. The wet habitat found within the rainforest is perfect for assuring their survival, but may also pose a threat if heavy rains or brisk streams wash food supplies away. Many dart frogs drowned when caught in the pathways of fast flowing streams. The Dart frog is also able to survive extreme dry conditions found within most tropical and jungle settings providing they hide beneath a rock,or climb tall trees seeking shelter under leaves and other tropical plants.

The Strawberry Dart Frog is unique in some ways, and seeks to house them-selves within the Bromeliad Plant. The broad leaves of the tropical plant fold over one another to form a cup, which holds water from the heavy rains. The frog will lay her fertile eggs, visiting them a few times per week providing nutrition until they later hatch into tadpoles. The newly born tadpole will swim inside the cup-like house for weeks until growing into tiny frogs.

Metamorphosis
The life cycle of poisonous dart frogs is no different from any other frog species, except for the poisonous glands found on the outer layer of skin. The process of changing from a tadpole into an adult frog is referred to as metamorphosis.

When the dart frog is born, they spawn their eggs on water, protected by a jelly like film and grow on nutrients provided by the internal yoke. The egg soon begins to create a cell, which later splits into two cells that form the embryo, or better referred as a tadpole.

Inside the cell, the organs and gills begin to form. The embryo will grow for 20 to 25 days at which time they hatch, and attach themselves onto the backs of the mother Strawberry Dart Frog. She later carries them into water where they may feed on algae or unfertilized eggs. The tadpole stage is brief in comparison to other amphibians and can last between three days to a little more than 8 weeks before growing into an adult frog.

The tadpole begins to develop hind legs first followed by the forelegs. At nine weeks, their tails become smaller and their lungs begin to develop as they grow. New skin begins to form over the old, allowing the frog to shed their skin and lips. The mouth widens and their lungs are now fully developed. By the end of the sixteenth week, the frog is fully developed and ready to survive on land and water.
To find out more about the life cycle of frogs, or purchase “GROW A FROG KIT” go to http://sciencekit.com/ig0021687/p/IG0021687/, or http://allaboutfrogs.org….S. Powell, 2010.

Resources:

1.) http: www.tooter4kids.com/Frogs/life_cycle_of_frogs.htm
2.) http://allabout frogs.org/weird/general/cycle.html
3.) Teacher.scholastic.com/lessonrepro/lessonplans/probook
5.) Poison Dart frogs, Jennifer Owings Dewey, boyd Mills Press, Honesdale, Pennsylvania, 1998.
6.) The Search for Poison-Dart Frogs, Ron Fridell, Franklin,Watts, Adivision of Scholastic, Inc., 2001.
7.) Poison Dart Frogs, Up close; Carmen Bredeson, Enslow Publishing, Inc., Berkeley Heights, NJ 2009.
8.) http://en.wikipedia.org/wiki/strawberry_poison-dart_Frog.

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