Though some may find them a bit creepy-crawly, spiders play an important role in our ecosystem. Animal Planet venom expert Donald Schultz showcases some fascinating species.

Mexican Red-Kneed Tarantula
Black with bright-red knees, this spider species grows up to 8 inches, has a life span of about 30 years, and lives along the Pacific coast of Mexico and in southern parts of the United States. They can't digest solid food, so in order to eat, they bite their prey with their fangs and inject them with venom. The venom kills the prey and then liquefies it, allowing the tarantula to suck out the resulting fluid. Their front two legs are used for holding prey; the remaining six are used for walking.

Chilean Rose-Haired Tarantula
Kept as pets around the world because of their quiet, slow-moving, and easy-to-handle nature, this tarantula is easy to care for and requires very little space. Named for the subtle rose shade of its hair, this species doesn't typically bite, but does have a freaky habit of using its fangs to climb.

Cobalt Blue Tarantula
Thought to be the fastest and most aggressive tarantula species, this spider is found in the tropical forests of Southeast Asia and preys on anything that it can overpower, including small vertebrates such as mice and birds. While most tarantulas use their hairs as a defense, these spiders rely on their painful bite.

Black Widow
Native to the United States, black widows have venom that is thought to be 1,000 times more potent than the dreaded Mohave rattlesnake. They breed actively, and while their bite can be fatal, there are very few deaths to humans recorded versus the number of bites. The female black widow will often eat the male after mating. Using their webs, they are able to capture large animals, including snakes.

Goliath Birdeater Tarantula
The largest spider species in the world, this tarantula grows up to 13 inches and is native to northeastern South America. Because of their size, they have a fair amount of meat on them, and are eaten by many things, including, in some parts of the world, humans. They are very successful ambush predators, and rub their fangs together to make hissing sounds.

Resources
For more information about spiders studied by venom expert Donald Schultz, visit donaldschultz.com or donaldschultz.blogspot.com, and watch "Mission: BIO RECON," premiering January 5, 2010 on Animal Planet.