"Finding new life in caves is my most favorite aspect of caving," Dawn says. Caves introduce many life forms to their visitors. Dawn sees plenty of life in the caves she explores. Puerto Rico's Cueva de las Culebrones, or "Cave of the Snakes," houses more than 300,000 bats, she recalls. At dusk, 7-foot-long boa snakes hang from the entrance to catch bats for dinner. Inside the cave, Dawn says the walls are covered with whip scorpions and cockroaches. It looks like the walls are moving!