Large Rain Forest Cats
Large cats pose a threat to the snakes of the rain forest. In the Amazon, jaguars -- large, spotted cats that resemble cheetahs -- are one of the few animals large enough to consider tackling a boa constrictor or other tropical snakes. Other large feline predators include jungle cats, which are native to Southeast Asia, and the pumas of South America.
Other Snakes
Snakes frequently prey on other snakes in the rain forest. This usually occurs because certain species are larger than other species. For example, a king cobra may prey on a pit viper because it has the advantage of superior size. Rain forest snakes are often most vulnerable to animals within the very same suborder -- Serpentes themselves.
Larger Reptiles
Given the abundance of bodies of warm water in rain forests, large, water-dwelling reptiles also will prey on snakes. Crocodiles, for example, favor anacondas in the Amazonian rain forest. Their strong jaws and stealth in the water allows them to take dangerous prey by surprise.
Humans
Unfortunately, humans post the most dangerous threat to snakes in tropical rain forests. While not strictly speaking "predators" of snakes, the deleterious effect of people's presence on snake populations cannot be denied. Logging businesses clear rain forests for their valuable lumber, destroying snakes' natural habitats and disrupting their development. Housing developments and urban expansion also upset the natural habitats of snakes and other species. The result is that the populations of several species of tropical snake are dwindling, and a few species, such as the king cobra, are officially endangered.