Zoological Investigations

So, I had this great thought about all the road-killed dogs, cats and iguanas I see on the drive from Lajas, Puerto Rico to work at the Cabo Rojo National Wildlife Refuge every morning at 5:30 a.m..

There are more chicks, chickens and roosters roaming about the streets than there are cats, dogs and iguanas, and yet despite this I have not seen one dead chicken. That got me excited; maybe chickens are much smarter than we generally give them credit for? Well, the end of this aside is that right after this I saw a dead chicken in the road. Figures.

Yet, what is even more rare than a road-killed chicken in Puerto Rico, and a more interesting subject for that matter, is Epicrates inornatus — the Puerto Rican boa.

The Puerto Rican boa is a rather drab looking brownish snake with patterning in shades of brown and black. The largest snake in Puerto Rico, most of the boas sighted have been around 2-2.5 metres long, though boas of up to six metres in length have been reported.

Like other boas, E. inornatus kills its prey by constricting. It is non-venomous and eats insects, other invertebrates, birds, and small mammals introduced to the island such as mice and rats. The Puerto Rican boa has also been observed hanging outside the mouths of caves in the limestone karst areas of the islands where they are sometimes able to catch bats leaving their roosts. Holy bat-eating snakes, man!

The Puerto Rican boa is ovoviviparous. Eggs develop within the female and she gives birth to live young, generally around 20 or 25 once per year. As in other ovoviviparous snakes, E. inornatus have been observed basking in the sun to speed and regulate development of the young. This behaviour can also aid in increasing the speed of digestion, something that is important for animals that eat relatively large prey whole.

Not much is known about the habits of young Puerto Rican boas as few have been observed in the wild. They are not currently kept in captivity due to general lack of knowledge about proper care and husbandry. Historically, humans hunted the Puerto Rican boa in order to extract its fat reserves for snake oil used in folk remedies. This process usually results in the animal’s death, and to some degree this practice is still performed today by poachers.
As its name implies, the Puerto Rican boa is endemic to the island. It is also listed as endangered by the United States Fish and Wildlife Service (USFWS) and the International Union for Conservancy of Nature (IUCN). The main reason for this listing is our old friend habitat loss. The human population on Puerto Rico has increased from approximately 40,000 about 500 years ago to around 3.9 million today. As a result of the huge increase in humans, much of the island has been deforested and converted to cropland (cane sugar, coffee, agriculture) and urbanization is widespread.

Yet we must look for the bright side, as it is all we really have, no? Gloriously, hopefully, desperately, it has been argued the boas are more common than previously believed. Population estimates and species range have not been thoroughly determined for E. inornatus, although the snakes are believed to be most prominent in the northwestern area of the island in the Caribbean National Forest.

Much remains to be learned about the Puerto Rican boa, and it may be that they are one of the few endemic species here on Puerto Rico actually benefitting from introduced species such as mice and rats. Go eat the vermin, Epicrates inornatus! I don’t want our mist nets to smell like rat pee anymore!