The name of the Black-headed Bushmaster (Lachesis melanocephala) or Plato Negro, it’s local Spanish name, are derived from the Greek Lachesis which means ‘the personification of fate’, melanos meaning ‘black’ and cephalo meaning ‘head’. It is one of Costa Rica’s largest pitvipers, and one of the world’s largest venomous snakes, they can reach a total length of 240 cm, with males growing larger than females. What makes snakes in the genus ‘Lachesis’ special is that they are oviparous, they lay eggs which are incubated in the environment, this is a feature that is uncommon in pitvipers from the Americas. The eggs are laid in abandoned mammal burrows and are guarded by the female.
Still little is known about the natural habits of this species in the wild, but it has been recorded to be terrestrial, crepuscular and nocturnal.
The Black-headed Bushmaster is the rarest of all bushmasters, this due to its limited distribution range. The range is from the central Pacific region, with an old record from Puriscal, all the way south to the Osa Peninsula and adjacent areas, from sealevel up to 1600 m elevation. The species has been reported in Panama, but like everywhere throughout its distribution, reports are scarce.