The Brown Tree Snake - Boiga irregularis

When we first got to Guam, the locals said that there "were no snakes on Guam"--well, these locals were badly misinformed. Because there was a tiny, obscure "blind-snake" of the Genus Typhlops sp. that lived in the detritus and leaf litter on the floors of Guam's "limestone forests". Then, a few weeks after we arrived on Guam, my Mom had the shock of her life.... there was a full-sized "brown-tree snake" coiled around the fuse box next to our refrigerator in our kitchen. Yup... No snakes on Guam. Yeah, right.

In 1969, they were rare. But you could still see one occasionally in the southern areas of the island--and particularly near the Navy Base on the west side of the island. (Maybe we saw a lot because we were always boonie stomping on the island--we were always in the forests and near the rivers and shorelines.)

Every morning, we'd wake up to the birds making a ruckus in the trees surrounding our home. However, by 1975, bird-songs weren't that prevalent around the island. By 1980, it was rare to hear birds making any noise anywhere around the island. That was the clue that something was drastically wrong. Also, in the meantime, by 1975, snake sightings were becoming more and more frequent. Folks finally admitted that there were indeed snakes on the island.

It's theorized that Guam's brown tree snake (Boiga irregularis--which is native to the Solomon Islands and Papua New Guinea--maybe made its way to the island during shipments of military gear out of the Solomons after World War II (some say in the 1950s). The shipments would be stored at the Naval Base on the island until container ships and freighters could be arranged for further transportation. The snakes may have been taking shelter inside the military equipment when it was being packed up... then, when they arrived on Guam, left the safety of the equipment to search for food. Other theories say that the snakes (or perhaps a single female with eggs) may have come to the island in potted plants--with the same results.

The snakes found an island with native wildlife unprepared to handle such an efficient and aggressive predator. Some of these native wildlife included the Guam rail--a flightless bird that had for many, many years survived without having to fly. The snakes made quick meals out of these birds and their eggs. The snakes also eat the island's skinks (small lizards), tree frogs, insects, rodents (mice, rats), the eggs and young of the monitor lizards, and even small domestic animals and their young (chickens, kittens, puppies).

Dozens of bird species have been wiped out--many that had been found nowhere else on earth, and the snakes have reached huge population densities reported to be as high as 15,000 snakes per square mile.

The snakes are mostly nocturnal (unless extremely hungry, then you'll find them out during the day), they are arboreal (they do most of their hunting and living in trees), and they aren't picky eaters--they eat darn near anything that moves and that's small enough to engulf in their mouth. They are oviparous--in other words--they lay eggs. Also, the snakes are venomous. The good thing is... they are considered "rear-fang" snakes of the Colubrid family, and although they are related to cobras, their rear-fangs and venom are not considered to be dangerous for humans. (Although, if one chewed on you for a while --something that might fit in their mouth so the fangs could inject the venom--such as a finger, a toe, an ankle--you might have a nasty wound and suffer medical complications from the toxins in the venom.)

A side note: the snakes on Guam frequently crawl into power transformers and try to traverse parallel power lines, which results in both an electrocuted snake and frequent power outages.