And now for something completely different…

Now, I’m fairly certain that you guys enjoy looking at a nice critter picture or two. Or three. Or a hundred. (Looking over the Zooniverse stats for membership and ID counts is always a humbling and awe-inspiring experience!) To mix it up a bit, and to give you all a better feel for the scientific background I am coming from, here is a taste of what I experienced during my last job before starting graduate school. I worked for the USGS on the Pacific island of Guam, conducting research on the invasive and highly destructive Brown tree snake (Boiga irregularis).



Photo Credit: Meredith S. Palmer

For those of you who aren’t familiar with this case study, the island of Guam was invaded in the 1960s by what was most likely a single pregnant female Boiga. Over the course of the next few decades, this generalist predator caused the extirpation of almost all native forest bird species, destroyed all nesting seabird populations, led to the extinction of 2/3s of the native mammalian life, and contributed to drastic declines and loss of native reptile and amphibian populations. This situation is highly unique in that it was the first (and remains one of the only) situations in which an invasive reptile caused such a degree of ecological damage. There is currently a higher density of Boiga on Guam – 13,000 per square mile – than there is of all combined snake species in the Amazon basin. Snake populations continue to be sustained on invasive skinks and pose not only severe ecological threats to Guam and surrounding islands, but also cost the island economy millions of dollars per year through losses relating to power outages caused by snakes, snake bite hospitalizations, decline in tourism money, the costs involved with ensuring that snakes do not leave the island, and agricultural losses.

Brown tree snake munching on an invasive gecko species


Photo Credit: Bjorn Lardner

A few of the species still on island, including a mangrove monitor, the moth skink, the highly endangered Mariana fruit bat (attempting to nest, apparently, in my hair), and another native skink species, the blue-tailed skink.

Photo Credit Meredith S. Palmer

Photo Credit Meredith S. Palmer

While the island itself is beautiful, due to the snake, it was completely depauperate of animal life. It is a Twilight Zone experience to walk through a forest devoid of any natural sounds, without crickets chirping or birds calling. The real beauty and biodiversity of Guam lies underwater, in the coral reefs and shallow oceans that surrounding the island – a place I would retreat to often.

The ocean’s vertebrate life (the massive pink object on the left is a dead sperm whale which snagged up on the reef half a mile off-shore)

Photo Credit: Meredith S. Palmer

Photo Credit: Meredith S. Palmer

The tropical fish diversity in Guam was absolutely mind-boggling. In addition, nothing would liven up a good snorkel like running into a ferocious eel or a encountering one of these enchanting sharks.

Photo Credit: Meredith S. Palmer

Photo Credit: Meredith S. Palmer

But everybody knows that invertebrates are really where it’s at. Cephalopods!


Photo Credit: Meredith S. Palmer

If anyone has questions about the snakes or invasive species situation on Guam, please feel free to ask. I can also highly recommend the USGS Brown tree snake lab website ( and the excellent book, “And No Birds Sing”, by Mark Jaffe, which documents the process by which scientists discovered the culprit behind these rapid extinctions.


7 responses to “And now for something completely different…”

  1. elfinelvin says :

    Interesting post Meredith, but what really caught my attention is the smiling woman with the (huge!) bat in her hair. I’d like my friends, who think bats are evil terrors, to see that. Maybe it would help them understand that even if, for some bizarre reason, a bat did land in their hair, it’s not the end of the world.

    • meredithspalmer says :

      It certainly is not! That gorgeous bat is one of the endangered Marianas fruit bats that we raised at the Guam National Wildlife Refuge. While the bat has been almost entirely extirpated from the island, we maintained a small colony (primarily for education purposes). These bats were extraordinarily friendly and would quite happily climb all over you and into your bags and pockets. This female was apparently attracted to curly hair and also liked to lick people, like a puppy!

  2. Tor Bertin says :

    Quick question regarding snake density:

    How much heterogeneity is there in snake density across the island? Are they relatively homogeneously distributed, or are there pockets of higher densities? If so, do they have any indication what drives those hypothetical pockets?

    • meredithspalmer says :

      Snakes seem to fare far better in urban areas than in the forests, due to food supply. In the jungle, they have eaten away most of their prey base. The human-populated areas on island, on the other hand, are full of food waste, which supports high rodent (prey) densities. The snakes are certainly healthier in these areas. For example, the largest specimen I ever caught was approximately 11 feet long (they’re usually 6 feet, at the max), and we pulled him out of the parking lot at the Micronesian Mall.

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