The golden lancehead has developed a number of physiological and behavioural differences to the Bothropoides species of the mainland. Like other pitvipers, it uses its heat-sensitive pits to detect prey, and possesses a pair of long, hollow fangs that fold against the roof of the mouth when not in use, being brought forward to inject venom (3).
However, unlike the mainland species, which feed mainly on rodents, the golden lancehead has switched to a diet of birds due to an absence of small mammals on Queimada Grande . Whereas rodents are bitten and then released, the snake then tracking the prey until it has safely been overcome by the venom, the golden lancehead must retain hold of the bird and kill it quickly, to prevent it flying away and being impossible to follow. The bird is therefore held in the mouth after being bitten, and the venom of the golden lancehead works unusually quickly, being three to five times more toxic than that of any of the mainland species (2) (4) (6) (9).
The golden lancehead is also more arboreal than other species, able to climb trees in search of birds, and is active during the day, at the same time as its prey (2) (4). In addition to birds, some lizards and amphibians may be taken, and the juvenile golden lancehead feeds mainly on scorpions, amphibians, lizards and other snakes (4).
The golden lancehead is thought to mate between March and July, before giving birth to live young the following January to April. Litter size is smaller than in the mainland species, at around 2 to 10 young, compared to 18 to 30 in Bothropoides jararaca (4) (6) (10). The young measure around 23 centimetres in length at birth (2), and may be more nocturnal than the adults (4). The golden lancehead is unusual in that it appears to exist as three sexes: males, females, and ‘intersex’ females, which possess both female and reduced male genitalia (4) (6) (11).