Guam brown tree snake invasion

Brown tree snakes, native to northern Australia and nearby islands, arrived in Guam after World II, likely as stowaways on military cargo. Since the 1940s the species has caused local extinctions of birds and reptiles and triggers hundreds of power outages each year by climbing utility poles.

A July 2026 long‑read genome sequencing study published in *Science Advances* uncovered thousands of structural variants—especially in genes linked to immunity and smell—within the invasive population. Researchers say these hidden genetic variations explain how a founding group of only a few individuals avoided an expected inbreeding bottleneck, adapted rapidly, and expanded to densities of up to 30,000 snakes per square mile.

The findings suggest the Guam invasion is more resilient to control measures than previously thought and provide broader insights into how small, inbred or endangered populations may retain unexpected adaptive capacity, informing both invasive‑species management and conservation biology.