|MadSci Network: Zoology|
Hi, Brett. You're investigating a very interesting group of frogs. "Poison dart frogs" are members of the Dendrobatid family, and there are over a hundred different species. Because of this, and because they are not very well studied in the wild, I'm afraid I can't give very specific answers to some of your questions.
1) How do zoos catch the frogs for the displays ?
Dendrobatids are easier to catch than many other frogs their size. They are brightly colored and are active during the day. They are small, however, usually between half an inch and two inches long, and they are very active. Collectors should be careful to use gloves, because there are a couple species whose poison can be fatal to humans.
2) How many eggs do they lay at a time?
This depends on the species of frog. Poison frogs are unusual among frogs in two respects: first, they don't lay their eggs in water. Instead, they lay them in a damp place on land--or else the mother will carry the eggs on her back until they hatch! Secondly, the parents will guard the eggs and take care of the tadpoles after they hatch (at least until they get the tadpoles into water), whereas most frogs just lay their eggs and leave them. Since they take care of the eggs, they don't have to lay as many as other frogs. They can lay as few as 6, or as many as 100--again, this depends on the species.
3) How does the poison come out of their skin?
Poison dart frogs have special glands in their skin that secrete the poison, much like the glands in your skin that make you sweat.
4) How long do they live?
This is another area that we don't know very much about. They have been known to live 8-10 years in captivity, but they haven't been studied in the wild enough to know how long they usually live. We do know that animals generally live longer in captivity than in the wild.
5) How long is their tongue?
This will also depend on the species, but a good average is about 2/3 of their body length.
If you want to explore more about poison dart frogs, a good place to start is http://18.104.22.168/index.html (the Dendrobatid frog page).
There's some good information there, and links to many other sites.
Try the links in the MadSci Library for more information on Zoology.