40 Fun Facts About Brown Tree Snake

What does Guam scatter by helicopter over its forests, laced with poison, to kill brown tree snakes?

Dead mice carry the dose: in one aerial trial over a 55-hectare forest plot, 11 of the 30 radio-tagged snakes there died.

With its forest birds eaten by brown tree snakes, Guam's jungles hold up to 40 times more of what?

Spiders boomed because the lost birds ate them and competed with them for insects; hikers on Guam now carry a stick to knock the webs out of their path.

Which everyday painkiller is so toxic to brown tree snakes that Guam uses it as a poison?

Acetaminophen, the drug in Tylenol, kills the snakes at a dose of just 80 milligrams, and in one treated test plot not a single snake survived.

Guam's brown tree snakes climb wide, smooth poles with a newly found movement named after what?

A lasso is what the snake's body resembles as it loops round the pole and inches upward, adding a fifth mode of snake movement to the four that had stood for nearly 100 years.

Brown tree snakes climbing into equipment on Guam caused over 1,600 of what in one 20-year span?

Power outages follow when a snake climbs the lines or crawls into a transformer, and the worst of them have blacked out the whole island.

Which animals are trained to check outbound cargo on Guam for stowaway brown tree snakes?

Dogs sniff through freight before it leaves the island, and other teams use them to track down snakes loose in the forest.

Which amphibian is one of only two proven predators of the brown tree snake identified in a study?

Cane toad releases were never tried: like the other proven predator, a black snake, it eats almost anything and would have menaced the wildlife it was meant to save.

Brown tree snakes reached Guam as military stowaways in the years just after which conflict?

World War II left Guam a busy military hub, and by 1952 a snake from the South Pacific had slipped ashore, probably hidden in ship cargo.

Direct military flights from Guam put which US state most at risk of a brown tree snake invasion?

Hawaii found eight brown tree snakes between 1981 and 1998, every one linked to vehicles or cargo arriving from Guam.

Brown tree snakes belong to a genus nicknamed for having vertical pupils like which animals?

Cats lend their name to the whole genus, the cat-eyed snakes, whose slit pupils suit hunters that work the treetops after dark.

Where in its mouth does the brown tree snake carry the small grooved fangs that deliver its venom?

At the back is an awkward spot for biting people: the snake must open its mouth as wide as it can to bring its fangs to bear, so a grown person gets only a small dose.

Lacking hollow fangs, how does a brown tree snake work its venom into an animal it has seized?

By chewing, the snake lets venom seep along the grooves in its fangs by capillary action instead of injecting it through a hollow needle.

Brown tree snake bites have caused serious medical trouble only in which group of people?

Young children are at risk because their low body mass makes a small dose count, a real worry on an island where the snakes find their way into homes.

What does the bad-tempered brown tree snake typically do when it feels cornered or threatened?

Strikes repeatedly, lunging again and again at whatever alarmed it: a fierce show from a snake whose bite is not considered dangerous to a grown person.

Besides New Guinea and nearby islands, the brown tree snake is native to coasts of which country?

Australia is home to far deadlier snakes; the brown tree snake lives along its coast from the Sydney area round the tropical north to the Kimberley.

Boldly banded reddish brown tree snakes from the north of their native range go by which nickname?

Night tigers wear rich reddish-brown and creamy-white bands, a far flashier coat than the plain brown most of the species is named for.

The brown tree snake belongs to which family, the largest of all the snake families?

Colubrids are mostly harmless to people, but a minority, the brown tree snake among them, carry short grooved fangs and a mild venom.

Besides ship cargo, brown tree snakes probably reached Guam by crawling into which part of aircraft?

Landing gear bays offer a dark, sheltered hiding place, which is why aircraft and freight leaving Guam are still searched for stowaways.

Stray brown tree snakes from Guam have even been reported in which state in the continental US?

Texas found its stowaway in Corpus Christi, in a cargo box shipped from Guam, though the species has never established itself anywhere on the US mainland.

Which Japanese island has reported sightings of stray brown tree snakes from Guam?

Okinawa joins Wake Island, Tinian and Diego Garcia on the list of far-flung places where stowaways from Guam have been sighted.

Hunted out of Guam's forests by brown tree snakes, the sihek is what kind of brightly coloured bird?

A kingfisher with a rusty-cinnamon head and iridescent blue feathers, the sihek survived only in captivity for decades after it vanished from the wild in the 1980s.

Zoo-bred sihek from Guam were freed in 2024 on which Pacific atoll, far from any brown tree snakes?

Palmyra Atoll gave the nine released birds a safe start, and in 2025 they produced the first sihek eggs laid in the wild in nearly 40 years.

Guam's flightless ko'ko', all but wiped out by brown tree snakes, belongs to which group of birds?

Rails are ground birds built to run, and the ko'ko' once numbered 60,000 to 80,000 before biologists caught the last wild ones in the 1980s to breed them in safety.

Starlings that survived Guam's brown tree snakes keep its forests growing by spreading what?

Seeds come from the pulp the starling eats, and with the other feeders gone it is the only native bird left on Guam to carry them through the forest.

On Guam the brown tree snake has few natural enemies apart from feral pigs and which native reptile?

Mariana monitor numbers never checked the invasion, and as the snakes stripped the forest of prey this big predator turned to eating invertebrates and raiding garbage.

What kind of animal is the fanihi, a furry, winged Guam pollinator also hit by brown tree snakes?

A fruit bat called a flying fox for its fox-like face, the fanihi pollinates Guam's forest trees as it feeds.

Sihek and ko'ko', names of Guam birds hit by the brown tree snake, come from which language?

Chamorro is the indigenous language of Guam, and the programmes working to bring the island's birds back now use its names for them.

Brown tree snakes hide up to a dozen oblong eggs in hollow logs, each with a shell of what texture?

Leathery shells need shelter from drying and heat, so the mother picks hollow logs and rock crevices, and the eggs hatch about 90 days later.

When are brown tree snakes on Guam thought to breed?

All year round breeding helped the invaders multiply until some forests held more than 100 snakes per hectare.

Besides venom, how does a brown tree snake often hold struggling prey still while it feeds?

Coiling around it like a constrictor pins the animal in place, giving the snake time to work its fangs in.

A 2018 Guam study tested which low-powered weapons as a cheap way to kill brown tree snakes?

Airsoft guns did the job, though the study concluded that higher-powered models firing larger ammunition were the ones worth using.

Besides wild birds and pets, brown tree snakes on Guam have learned to prey on which farm animals?

Poultry losses add to the snake's bill on Guam, where it turns up so often around houses, coops and caged birds that it counts as common wherever people live.

The brown tree snake and which other invader together caused over $16 billion in damage since 1986?

American bullfrog and brown tree snake costs were counted in ruined farm crops and other costly damage, on top of the harm the pair do to wildlife.

A toxin in brown tree snake venom is highly toxic to birds and lizards but not to which animals?

Mammals are unaffected by irditoxin in laboratory tests, while it blocks nerve signals to a bird's muscles: fitting for a snake that emptied Guam's forests of birds.

Guam's swiftlet, one of two native forest birds to outlast the brown tree snake, nests where?

Limestone caves hold its colonies, with nests fixed high on walls and ceilings in total darkness, where the birds find their way by echolocation clicks.

The brown tree snake's native range runs from Indonesia through New Guinea to which island nation?

Solomon Islands forests sit at the eastern end of a range spread across islands of every size, at elevations of up to 1,200 metres in New Guinea.

Rescuing Guam's last ko'ko' from brown tree snakes probably wiped out which parasite unique to them?

A louse found only on the ko'ko' vanished when the captured birds were deloused to help them survive, a case of extinction caused by a rescue.

After brown tree snakes beat cylinder guards on Guam nest boxes, scientists tried which new shape?

Ice cream cones, narrow at the base and wider at the top, were meant to stop a climber that an ordinary cylinder could not.

To keep brown tree snakes from the nests of Guam's last native crows, what was fitted to the trees?

Electrical barriers could not save them: the few crows left were too old to breed, and by 2011 the species had vanished from Guam.

Since 1995, over 100 captive-bred ko'ko' have been released on which island 40 miles north of Guam?

Rota offered forest free of Guam's swarms of snakes, and by 2019 about 200 of the birds were living wild there.