I’ll admit that this week’s fact isn’t particularly fun, but it is good food for thought nonetheless.
Island ecosystems are particularly vulnerable to the threats posed by invasive species, and Guam is one of the most startling examples. A tiny island in the Western Pacific, Guam became a U.S. territory in 1898, but the brown tree snake (Boiga irregularis) arrived in the late 1940s. The reptile is native to Australia, Papua New Guinea, and the Solomon Islands. The snakes on Guam are most similar to those found in northern Papua New Guinea and were most likely inadvertently imported by U.S. military cargo transports to the island during and after World War II.
The brown tree snake averages three or four feet long, but can reach up to 10 feet, and as their name suggests, they are tree-dwellers. They primarily feed on birds and small lizards, so when they came to Guam, the snakes found a smorgasbord of prey that had not developed the defensive features and behaviors necessary to evade them. By the early 1980s, the native bird population had all but evaporated. Birds like the Guam Flycatcher and Mariana Fruit Dove haven’t been seen on the island for over three decades. According to the Smithsonian, “of the 18 species of native Guamanian birds, seven are extinct, two are extinct in the wild…six are rare, and three are uncommon.”
The USDA has established removal programs, but the current population of brown tree snakes in Guam, while they are doing nothing more than surviving and thriving as any normal snakes would, remain a threat to both the ecosystem and the economy of the island. Guam also happens to be a major travel and transport hub, making a potential snake invasion a major concern for other Pacific islands, like Hawaii.
Here are for four more facts about the threatened ecosystem of Guam and its resident, problematic population of brown tree snakes:
- Guam has the highest density of snakes anywhere in the world, with an estimated 14,000 brown tree snakes per square mile – and the island is only 212 square miles!
- There is only one other snake on Guam and it is also an introduced species.
- Brown tree snakes commonly cause power outages on the island.
- The disappearance of the native birds may be responsible for the decline in certain tree species and subsequent warming of Guam’s forests.
#FunFactFriday is a biweekly series where I dedicate a post to a completely random, interesting fact – because the world is a pretty darn random, interesting place.