St. Lucian Lancehead

“Only three currently recognized species of vipers are endemic to the Caribbean: the Aruba Island Rattlesnake (Crotalus unicolor) on Aruba, the Fer-de-Lance (Bothrops lanceolatus; it’s worth noting this common name was first applied to this species) on Martinique, and the St. Lucian Lancehead (Bothrops caribbaeus) on St. Lucia. A few days before Christmas in 2021, my sister and I visited the lush island of St. Lucia in search of its endemic viper.

Only 14 miles at its widest, St. Lucia is a small island in the Lesser Antilles island chain of the southeast Caribbean. Martinique neighbors it to the north and Grenada to the south. It has a long, tumultuous history, first changing hands from the Carib to the Arawak peoples in pre-colonial history, then experiencing a volatile period of ownership between the British and French during the colonial period (this included a successful slave revolt led by a woman named Flore Bois Gaillard). The legacy of French and English competition for the region is well illustrated by the fact that St. Lucians speak English and drive on the left side of the road, while Martiniquais, only 20 miles away, speak French and drive on the right.

The entire island is classified as tropical rainforest according to the Köppen climate classification; however, it contains a variety of ecosystems that include dry forest, scrublands, and mangrove forests. The diversity of habitats and geographical isolation afforded to many Caribbean islands are perfect ingredients in the arising of endemic species, and St. Lucia is no exception. The list of endemic species on St. Lucia ranges from anoles to amazons, but for the purpose of this write-up I will only discuss the snakes. All five of the snake species historically found there are St. Lucian endemics. These are the St. Lucian Lancehead (Bothrops caribbaeus), St. Lucian Boa (Boa orophias), St. Lucian Blindsnake (Tetracheilostoma breuili), St. Lucian Racer (Erythrolamprus ornatus), and the extinct Underwood’s Mussurana (Clelia errabunda). While all the snake species found on the island are threatened to some degree, the racer and the mussurana have borne the brunt of St. Lucia’s ecological problems. Despite having fared slightly better than the now-extinct mussurana, the St. Lucian Racer only persists on satellite islands off the coast of St. Lucia. Declines in both species are directly attributed to the introduction of the Small Indian Mongoose (Urva auropunctata), which was introduced for the purpose of killing the lancehead. Ironically, not only did the mongoose eliminate what was probably one of the few native predators of the lancehead—the mussurana—it also ended up providing lanceheads with an additional food item. The biologist James D. Lazell, Jr. described it best in his description of the species in 1964:

“In Martinique and Saint Lucia, Bothrops, being essentially backward and illiterate, seem unable to distinguish mongooses from other small animals (e.g. rats), and therefore eat them with relish.”

While the island’s mongoose infestation may not do them in, the St. Lucian Lancehead is still an imperiled species. The IUCN lists it as endangered, and a collection of viper specialists placed it on a list of the 20 most endangered vipers in the world. Occurring on an already small island, its range has further contracted. The lancehead is thought to currently only occur in an isolated band of habitat in the northeast and south-central parts of the island. Habitat loss and direct persecution, including a bounty system and targeted hunts, are the primary threats to the species. Our Caribbean vipers, like most island endemic organisms, are some of the most vulnerable in the world, and it would be a tragedy to see any of them go the way of the dodo—or rather, the Underwood’s Mussurana.

Relative to other members of the Bothrops genus, information on the St. Lucian Lancehead is sparse. Generically, it is a large-bodied, generalist viper that inhabits wetter regions of the island. Phylogenetic studies have placed it as sister to the fer-de-lance (the Caribbean one, not the one you saw in Costa Rica) and nested it within the Bothrops asper–atrox complex. It likely split from its sister species ~5 MYA and from the complex ~6 MYA. As far as its natural history, I found information from the literature and personal anecdotes to be broad, contradictory, or unreplicated. Variables such as optimal time of year, weather, and microhabitats were particularities of the snake for which I ended up with more questions than answers. This made creating a game plan for my trip difficult. Accordingly, I figured herping as often as I could, in all habitat types, regardless of weather, might produce a snake.

Ultimately, it didn’t matter. Five hours after being picked up by my sister from the airport, we were driving near a creek to night-shine when I spotted the familiar shape of a viper in the road. I’d rather be lucky than good!” –– Calvin Vick