Terciopelo (or Fer-de-lance)
Bothrops asper • Order: Squamata, Suborder: Serpentes, Family: Viperidae, Subfamily: Crotalinae, Genus: Bothrops, Species: asper
Venomous Status
Highly Venomous (Solenoglyphous; featuring long, retractable, hollow fangs at the front of the upper jaw).
Danger Level
Extremely Dangerous. This species is responsible for the majority of serious snakebites in Costa Rica and Central America due to its proximity to humans and defensive nature.
Geographic Range
Found in the Neotropics, ranging from southern Mexico through Central America (including all of Costa Rica) into northwestern South America (Colombia and Ecuador).
Conservation Status
Least Concern (IUCN). Despite being persecuted by humans, they thrive in edge habitats and agricultural lands.
Physical Description
Large, heavy-bodied pit viper with a distinctly triangular/lance-shaped head. The pattern consists of series of dark, pale-edged triangles or 'X' shapes along the sides on a brown, gray, or olive background. The eyes have vertical pupils and there are visible heat-sensing pits between the nostril and eye. Scales are heavily keeled.
Size & Dimensions
The specimen in the image appears to be a large juvenile or sub-adult, roughly 80-100 cm. Adults typically range from 1.2 to 1.8 meters, though females can occasionally exceed 2 meters.
Habitat
Primarily inhabits humid lowland rainforests and premontane forests, but is highly adaptable to disturbed areas, agricultural plantations (coffee/banana), and rural gardens. Found from sea level to approximately 1,200 meters elevation.
Behavior & Temperament
Mainly nocturnal (active at 10pm as noted). While they prefer to remain camouflaged, they are famously defensive and will strike repeatedly if they feel threatened or are stepped on. They are ambush predators that often sit in a coiled position for long periods.
Diet & Feeding
Generalist carnivore. Juveniles often consume lizards and frogs; adults transition to a diet primarily of small mammals (rodents) and birds. They use an ambush strategy, striking and releasing prey before following the scent trail.
Reproduction
Viviparous (gives birth to live young). They are highly prolific, with litter sizes often ranging from 20 to 80 neonates. Breeding can occur year-round but often peaks with the rainy season.
Venom & Safety
Venom Type
Complex cocktail of hemotoxins, cytotoxins, and myotoxins causing severe tissue necrosis, systemic hemorrhaging, and coagulopathy.
First Aid Advice
Seek immediate emergency medical attention. Keep the limb immobilized and at or slightly above heart level. Do not use tourniquets, ice, or incisions. Antivenom (ICP Polyvalent) is highly effective and widely available in Costa Rican hospitals.
Look-alikes
Often confused with the Neotropical Rattlesnake (Crotalus durissus) which has a rattle, or the harmless False Fer-de-lance (Xenodon rabdocephalus) which has a similar pattern but lacks heat pits and possesses round pupils.
Conservation Status
Least Concern (IUCN). Despite being persecuted by humans, they thrive in edge habitats and agricultural lands.
Cultural Significance
Known as the 'ultimate' snake in Costa Rican rural lore. It plays a critical ecological role in controlling rodent populations but is also the primary driver of snakebite-related medical research in Central America.
Notable Features
Features loreal pits for heat-sensing (infrared vision). Known for 'caudal luring' as juveniles (using a yellow-tipped tail to mimic a worm to attract prey), though the yellow tip fades as they mature.
Notes
Costa rica 10pm