Critically Endangered
Golden lancehead
Bothrops insularis
Golden lancehead is a viper in the family Viperidae — Bothrops insularis, recorded as Critically Endangered and tied to Brazil.
Appearance
Its color pattern consists of a pale yellowish-brown ground color, overlaid with a series of dorsal blotches that may be triangular or quadrangular, broad or narrow, and alternating or opposite along the dorsal median. In captivity, this yellowish color often becomes darker, that may be the result of poor circulation caused by ineffective thermoregulation. A banded pattern results when the pattern is opposite.
Usually, B. Insularis grows to a total length (among them tail) of 70 to 90 cm (28 to 35 in), but it is known to reach a total length of 118 cm (46 in).
Range and habitat
B. Insularis is endemic to Queimada Grande Island, Brazil, called Snake Island. This island has a total area of only 43 hectares (430,000 m2. 110 acres; 0.17 sq mi). Travel to the island is strictly prohibited by the Brazilian government.
The species is found exclusively on the island of Ilha da Queimada Grande, off the coast of São Paulo state, in Brazil. The population of B. Insularis on the island was estimated in 2021, based on a combination of observations and two- and three-dimensional scanning of the island in 2015, to be between 2,414 (2D scan estimate) and 2,899 (3D scan estimate).
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Diet and breeding
It is likely to be found in trees while hunting for its prey, that consists mostly of birds, but it tends to seek shelter under leaf litter or in rock crevices during storms or after ingesting prey. Unlike other venomous snakes that tend to strike, release, and then track their prey, B. Insularis keeps its prey in its mouth once it has been envenomated.
This is thought to be an adaptation to hunting birds, as chemical tracking of prey after release—a practice used by other vipers—is much harder when airborne food sources are to be tracked. While other lanceheads have been observed shaking their tails to lure prey, this behavior has not been observed in the golden lancehead. Sexually mature B. Insularis snakes mate during August and September, and have been known to mate both in the trees and on the ground.
In crisis
This species B. Insularis is classified as critically endangered on the IUCN Red List for the following criteria: CR B1ab(iii)+2ab(iii) (v3.1 (2001). This means that the "geographic range" is estimated to be less than 100 km2 (39 sq mi), that this area is severely fragmented or known to exist at only a single location, and that a continuing decline has been observed, inferred, or projected for the area, extent, and/or quality of the habitat. The population trend was stable when assessed in 2004.
Golden lancehead is Critically Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Golden lancehead, Wikidata item Q670143. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.
