Danger lurks among the twigs and vines of the jungle floors in Western Colombia. This is the home to the dangerous and very toxic species Phyllobates terribilis ­ a frog. These brightly colored creatures of bright golden yellow, golden orange, or pale metallic green exude four steroid toxins from their skin, one of them being among the most toxic substances known to man-- batrachotoxin. Even handling one of these beautiful creatures could put your life in jeopardy.(2)
 
 

        Batrachotoxin is an alkaloidal steroid released through colorless or milky secretions from the granular glands (located on the back and behind the ears) of frogs from the genus Phyllobates.(2) When one of these frogs is agitated (such as when it feels threatened) or in pain the toxin is reflexively released through several canals.(10) Batrachotoxin (from the Greek word "batrochos" meaning frog and toxin meaning poison) was given its name by scientists John Daly and Bernard Witkop.(10) Along with collaborators, Daly and Witkop carried out the isolation of the pure alkaloid and determination of its structure and chemical properties.(1) Batrachotoxin is stronger than curare (another arrow poison used among South American Indians derived from plants of the genera Strychnos and Curarea) and ten times more potent than tetrodotoxin from the puffer fish. The estimated lethal dose for this non-protein poison in humans is somewhere between 2-200 µg.(2)
 
 

        It is interesting to note that the "poison dart" (or "poison arrow") frog does not produce batrachotoxin itself. It is believed that the frog gets its poison from eating ants or some other insect in their native habitat.(10) The insects obtain the poison from a plant source. Over the span of millions of years subtle modifications of the frog's receptors have been made so it has become insensitive to the effects of batrachotoxin. Frogs raised in captivity do not produce batrachotoxin and thus may be handled without the risk of death.(9)

        Of the Dendrobatidae family (especially Dendrobates and Phyllobates) over 100 toxins from skin secretions have been identified. (6) Frogs of the genus Dendrobates (of which there are 10 known species) are known as poison dart or poison arrow frogs as well. However, only the frogs of the genus Phyllobates produce the super deadly batrachotoxin.The native habitat of poison dart frogs is  the warm regions of Latin America in which the humidity is around 80 percent.(10)
 
 

For more great pictures and further information about poison dart frogs click on one of the links below.

http://library.thinkquest.org/C007974/2_2poi.htm
http://www.bubis.com/azureus/dartpics.html
http://www.dartfrogland.com/
http://www.cobras.org/article2.htm
 
 

(1) Catterall, W. A. Neurotoxins that act on Voltage-sensitive Sodium Channels in Excitable Membranes, Ann. Rev. Pharmacol. Toxicol. 1980. 20:15-43.

(2) Myers, C.W.; Daly, J. W.; Malkin, B. A Dangerously Toxic New Frog. Bulletin of the American Museum of Natural History 1978, Vol.161, Article 2.

(3) Catterall, W. A. Structure and Function of Voltage-Sensitive Ion Channels, Science. 1988. 50-61.

(4) Warnick, J. E.; Albuquerque, E. X.; Onur, R.; Jansson, S.E.; Daly, J.; Tokuyama, T.; Witkop, B.; The Pharmacology of Batrachotoxin. VIII. Structure-Activity Relationships and effect of pH, J. Pharm. Exp. Ther. 1975. 193:232-245.

(5) Toxicology: The Basic Science of Poisons, 3rd ed.; Klaassen, C. D.; Amdur, M. O.; Doull, J., Eds.; Macmillian Publishing: NewYork, 1986, pp. 378, 719.

(6) Tichy, W. Poisons: Anecdotes & Antidotes, Sterling Publishing Co.: New York, 1977, p.102-103.

(7) Toxicology, Haley,T. J.; Berndt, W. O., Eds.; Hemisphere Publishing Corporation: Washington, 1987, pp. 451-452.

(8) Venomous Animals and Their Venoms, Vol. 2.; Bucherl, W.; Buckley, E. E., Eds.; Academic Press: London, 1971, pp. 497-518.

(9) http://www.cobras.org/article2.htm

(10) http://library.thinkquest.org/C007974/2_2poi.htm

(11) http://www.biosite.dk/staabi/batrachotoxin.htm