A Swiss researcher Daniel Hofer has recently found that certain caecilians produce potent skin poisons from specialized poison glands. The poison prevents predation and the poison of the bright yellow caecilian of São Tomé Island ("Schistometopum thomense") in West Africa kills other animals kept in the same tank within a few days. The chemical contents of caecilian poison have not been well studied. Werner Himstedt has shown that the skin glands of "Ichthyophis" protects the eggs from germs and fungi. It has also been shown that these poisons are very different from those from other amphibians such as the arrow poison frogs.