Yellow-blotched palm-pitviper  (Bothriechis aurifer)

Classified as Vulnerable (VU) on the IUCN Red List (1).

The yellow-blotched palm-pitviper is a slender, green, venomous snake with a conspicuous, prehensile tail (2). This species can be distinguished from other members of the genus by the intricate patterns of yellow blotches on the body and a stripe extending backwards from each eye, although some individuals may lack these markings and appear uniformly green (2). While most yellow-blotched palm-pitvipers measure less than 70 centimetres, some individuals have been recorded measuring over one metre (2). Juveniles usually have a pale green head and body, with a striking yellow tail (2). The scientific name, aurifer, means ‘to bear gold’ and refers to the yellow-blotches of this snake (3).  The name ‘palm-pitviper’ relates to the habit of individuals coiling amongst small palms when ambushing prey, a behaviour exhibited by most members of this genus (2).

This species has a limited range, occurring in extreme west-central Chiapas, Mexico, and throughout the Atlantic drainages of the Sierra de los Cuchumatanes, Sierra de las Minas, and Sierra de Chuacús of Guatemala (2).

The yellow-blotched palm-pitviper mainly inhabits lower montane cloud forest at elevations from 1,200 to 2,300 metres, but has also been recorded in subtropical wet forests (2).

The yellow-blotched palm-pitviper belongs to a group of snakes characterised by a pair of heat-sensitive pits, located on each side of the head between the nostril and eye (4). The function of these sensory organs is widely debated, with roles in aiding thermoregulation (5), predation (6) and predator detection (7) hypothesised. The prehensile tail is an evolutionary adaptation to life in the trees; despite this, individuals are frequently encountered in low vegetation and even on the ground (2). The brightly coloured tail of juvenile yellow-blotched palm-pitvipers is a common trait amongst pitvipers (2), and resembles a wiggling invertebrate, which is used to lure potential prey (7). The loss of this bright tail colouration coincides with shifts in diet as the snake grows, from ‘cold-blooded’ prey items (such as lizards, amphibians and large arthropods) to ‘warm-blooded’ mammals (8). The yellow-blotched palm-pitviper is primarily active during the day (2). This is typical of pitviper populations that occur above 1,500 metres, whereas populations occurring below 1,000 metres are usually active at night (2). Like the majority of Neotropical pitvipers, this species gives birth to live young, but there is little information regarding reproductive cycles and litter size (2).

Although members of the genus Bothriechis are venomous, it is considered unusual for bites to result in fatality in humans (2). Bites from the yellow-blotched palm-pitviper, however, have reportedly caused at least one fatality in Guatemala (2). As with all vipers, venom is delivered through a pair of hollow, hinged fangs at the front of the mouth (9).

The yellow-blotched palm-pitviper is classified as Vulnerable on the IUCN Red List, due to severe fragmentation throughout the extent of its range, which is less than 20,000 square kilometres (1). This habitat fragmentation, caused by cloud forest being replaced by coffee and ornamental fern plantations, combined with collection for the international pet trade, is thought to be causing continuing declines in yellow-blotched palm-pitviper populations (1).

This species occurs in two protected areas; the Biotopo Mario Dary Rivera protected area and a protected area in the Sierra de las Minas, Guatemala (1). The yellow-blotched palm-pitviper is also listed as Threatened (Category A) by Mexican law (1).

View information on this species at the UNEP World Conservation Monitoring Centre.

For information on conservation efforts in Mexico see:

• Sky Island Alliance:
  http://www.skyislandalliance.org/home.htm
• The Nature Conservancy:
  http://www.nature.org/wherewework/northamerica/mexico