In addition to Cuba and the Bahamas, the Caribbean island chain contains an unassuming little island called St. Lucia. A rainforested, mountainous, volcanic island roughly 616 sq km in size, that was first inhabited by native peoples from South America early in the 2nd century. “Discovered” by good old Christopher Columbus in 1499, British attempts at colonization began in 1605 and French attempts in 1667. The island changed hands between British and French 14 times before achieving independence in 1979. Sugar plantations manned by African slaves made up the bulk of St. Lucia’s economy in the 19th century, whereas today the main economic boons consist of banana plantations and tourism. The island is inhabited today mainly by descendents of the early African slaves and has a population close to 200,000.
What does beautiful St. Lucia have to do with another great “Zoological Investigations” article, you ask? Interested readers might pass the hours by reading about theories of island biogeography and related concepts, perhaps even a little of Darwin’s On the Origin of the Species for good measure. On the other hand, they might simply choose to take my word that islands, by virtue of their remoteness from the mainland, tend to harbour uniquely adapted, endemic (those which aren’t found naturally elsewhere in the world) species and provide rich grounds for evolutionary processes to take hold, leading to interesting and sometimes really weird organisms and community interactions. Often, island species evolve in a relative vacuum, until oh, let’s say European settlers introduce hordes of ship rats ready to devour unsuspecting creatures that have never before faced predation. This, as you might guess, usually has disastrous results for island wildlife and let’s not forget what happens when us humans begin settling in and ripping up the land for natural resources and hotels — habitat loss and destruction, oh my.
So now you want to know what the hell is a fer-de-lance, eh? Well, my Canadian friends, that is a lovely French word for ‘spearhead’ (or the more literal and less poetic, “iron of the lance”) and refers to an extremely venomous snake that lives, you guessed it, on St. Lucia Island in the sunny Caribbean. Also known by its less beautiful sounding scientific name, Bothrops caribbaeus, the fer-de-lance is one of five species of snake found on the island (one of which is now extinct) and belongs to the family Viperidae (fancy talk for, “It’s a viper”).
The fer-de-lance is viviparous, which means that it incubates eggs internally and gives birth to live young, around 60 at a time. Gestating females move in and out of the sun in order to regulate their body temperature and incubate the developing young. They mainly eat birds and mammals, and have even been known to eat those crazy vicious carnivores, the mongoose. Hunting is primarily done at night, during which the snakes will rear into an S-shape, strike quickly, and then retreat while their prey dies a horrible, venomous death.
Pit vipers such as the fer-de-lance have unique structures called “pits” that are found in grooves on the head, which can detect infrared radiation (i.e. heat) emanating from their prey. This allows the snakes to quickly and accurately locate their prey in the dark. What’s more, the position of the pits is such that it allows for a type of “binocular scent” similar to how our human vision gives us depth perception and helps us to correctly gauge distances, most of the time.
The fer-de-lance is extremely venomous, and is considered by many as the most dangerous snake of Central and South America. It can inject 105 mg of venom in a single bite — milking the snakes for venom has yielded up to 310 mg — and causes more human deaths than any other reptile. In case you wondered, the lethal dose of venom for humans — based on some undisclosed average weight, I assume — is a mere 50 mg. The venom contains seven different toxins, including stuff that breaks down cell membranes, allowing that precious content to spill out all over the place and cause general mayhem in your poor, dying body, and proteins. The toxins also cause hemorrhaging, internal bleeding, painful swelling, and blood clot formation in humans.
Studies of the fer-de-lance undertaken by the National Forest Demarcation and Bio-Physical Resource Inventory Project have shown these vipers to be at a significant risk of extinction, primarily due to that old beast: habitat destruction, coupled with the introduction of invasive species such as opossum (manicou), rats, dogs, cats, feral pigs and mongoose, as well as hunting and chemical pollution from agricultural processes.
Fer-de-lance populations have declined significantly in beautiful St. Lucia over the last 50 years, and populations are now restricted primarily to two fragmented portions of the island. These snakes are not protected by St. Lucia’s Wildlife Protection Act, which was implemented in 1980. Three other species of fer-de-lance native to islands of Brazil, B. alcatraz, B. insularis, and B. pirajaiare are listed by the International Union for the Conservation of Nature (IUCN) as critically endangered and vulnerable (B. pirajai) but the St. Lucia fer-de-lance B. caribbaeus has not yet been assessed by the IUCN.