(genus Bothrops), extremely venomous snake of the viper family (Viperidae), found throughout tropical America in diverse habitats from cultivated lands to tropical forests. The fer-de-lance, known in Spanish as barba amarilla (“yellow chin”), is a pit viper (subfamily Crotalinae)—i.e., distinguished by a small sensory pit between each eye and nostril. It has a broad, triangular head and is usually about 1.2 to 2 m (4 to 7 feet) long. It is gray or brown, marked by a series of black-edged diamonds often bordered in a lighter colour. Its bite can be fatal to humans.

The Okinawa habu (Trimeresurus flavoviridis) is a large, aggressive snake found on the Amami and Okinawa groups in the Ryukyu Islands, often in human dwellings. It is usually about 1.5 m (5 feet) long and is marked with bold, dark green blotches that may merge to form a wavy, longitudinal band. Its venom is not especially potent but sometimes causes disability or death.

The jararaca, often confused with the fer-de-lance, is found chiefly in Brazil, where it is abundant in grassy regions. Its bite causes many deaths. It usually grows to about 1.2 m (4 ft) and is olive- or grayish-brown with darker brown blotches. The wutu, also South American, is a dangerous snake about 1.2 m long. It is brown, boldly marked on its sides with thick, dark semicircles outlined in yellow. The jumping viper is an aggressive, brown or gray Central American snake with diamond-shaped, crosswise markings on its back. It is usually about 60 centimetres (2 feet) long. It strikes so energetically that it may lift itself off the ground. Its venom, however, is not especially dangerous to man.