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Rattlesnakes are members of the pit viper family. All species in this family possess venom glands that produce a venom with two distinct poisons. The first contains a heart-lung depressant, while the second includes a tissue-disintegrating agent. Rattlesnakes have a rattlelike structure at the tip of their tail, which is shaken when the snake is threatened or about to strike.
Dorling Kindersley/BBC Natural History Sound Library. All rights reserved.