In parts of North America, certain caves and pits become seasonal shelters for enormous numbers of rattlesnakes. During winter, thousands of these venomous snakes gather together in underground dens ...
Better hope you don’t get bit by any of these venomous snakes. Top row: Robert Hamilton/Alamy; Wiki Commons; Sam Yue/Alamy. Middle row: Scott Travers; Design Pics Inc/Alamy; Dimitry Orlov/Alamy.