Micrurus sp. 

Micruroides euryxanthus

primarily nocturnal

ground-dwelling

primarily in mesic and dry forests, up to altitudes of over 2,000 m, some species also in stony or sandy arid areas; sometimes close to human settlements and in coffee plantations

conspicuous warning colouring consisting of black, red and yellow cross bands (a number of harmless colubrids also have this colouring)

when threatened, the end of the tail is raised in the air and moved back and forth; the head is sometimes hidden under the coils of the body

generally non-aggressive behaviour; accidents uncommon

nocturnal in warm weather, diurnal in cool

ground-dwelling

dry forests, A. bilineatus also in savanna-like regions

sturdy body, rarely over 1 m; A. bilineatus has 2 white lines along each side of the head

accidents due to A. bilineatus appear to be relatively rare

primarily nocturnal

ground-dwelling

in forested areas and plantations; often along rivers

sturdy body, length up to around 2 m or more

generally irritable; they dart forwards from a tensed position and often strike repeatedly

common cause of serious snakebites

Crotalus sp.

primarily nocturnal

ground-dwelling

open arid areas, from the lowlands to mountains; sometimes also in savanna-like grasslands, as well as sparse forest

stout body with characteristic rattle on the end of the tail; smaller species around 60 cm, the largest up to 1.5 m

a typical dry and high warning sound is produced by vibration of the rattle; during this process the body is coiled into a tight S-shape

in Mexico, where many species are found, the most common cause of severe snakebite envenoming

Lachesis sp.

nocturnal

ground-dwelling

primary rainforest, remote from civilisation

stout body, length up to 3.5 m!

relatively unaggressive during the day, marked defensive behaviour at night, neck is inflated and the tip of the tail is vibrated, then easily provoked into striking

as Lachesis hardly ever comes into contact with humans, accidents are relatively rare