Invasive species Brown tree snake

Origins & Arrival

100

what is Guam?

Guam is U.S. territory in the Pacific famously overrun by brown tree snakes.

200

Was the brown tree snack in World War II?

The brown tree snake arrived in Guam shortly after this global conflict ended in the 1940s.

300

Did brown tree snakes be found on ships (cargo) and aircraft?

Scientists believe the snakes likely stowed away on these two types of military or commercial transport.

400

Where is Papua New Guinea?

 Brown tree snake is naturally native to parts of Australia, Indonesia, and this neighboring large island nation to the north.

500

What is a genetic bottleneck (or inbreeding)?

This phenomenon—where a small founding population has a very low genetic variety—should have slowed the snakes down, but they thrived anyway.

Ecological Wreckage

100

were there millions of snakes?

Because they have no natural predators on Guam, the snakes population grew to an estimated 1 to 2 this unit of number.

200

Why did the snake population explode on Guam?

Guam had no natural predators, parasites, or competitors to keep the snake population in check, and local prey species had no evolutionary defenses against an arboreal (tree-climbing) night predator.

300

What ecological damage has it caused?

• It wiped out 9 to 10 out of roughly 12 native forest bird species (leaving isolated populations of only a few species like the Micronesian starling and Mariana swiftlet).
• It also caused declines or local extinctions of native lizards and the Pacific sheath-tailed bat, which disrupted pollination, seed dispersal, and insect regulation

400

How does it affect human infrastructure and the economy?

• The snakes climb electrical poles and wires, short-circuiting transformers and causing hundreds of power outages each year.
• This damages electrical equipment and costs millions of dollars annually in repairs and lost productivity

500

Are brown tree snakes dangerous to humans?

• They are mildly venomous with rear fangs. While generally not fatal to healthy adults, their bites can pose a serious risk to infants and young children

Ecological Wreckage

100

How are scientists and agencies trying to control them?

• Control methods include specialized traps, search dogs, cargo fumigation, and aerial drops of dead mice laced with acetaminophen (which is toxic to the snakes).