Are Timber Rattlesnakes Endangered? Status State by State

Global status: Least Concern

The IUCN Red List last assessed the timber rattlesnake in 2007 and classified it as Least Concern. That rating reflects the species as a whole: it still has a very large range across the eastern United States, from New England to Texas and Florida, with many populations in the Southeast and the central and southern Appalachians.

NatureServe, which tracks species across North America, ranks it as apparently secure globally, but rates it as critically imperiled or imperiled in many individual states, especially along the northern and western edges of its range. In other words, the snake is doing reasonably well where it is common and very poorly where it was always scarce.

Where timber rattlesnakes are endangered or threatened

Wildlife protection for timber rattlesnakes in the United States comes from state laws. The table below summarizes the main listings. State lists are updated from time to time, so check with the state wildlife agency for the latest status.

In many southern and Appalachian states, including Georgia, Tennessee, Kentucky and West Virginia, the timber rattlesnake is not state-listed and remains fairly widespread in large forests. In Pennsylvania, it is still found across much of the forested mountains, as described in our guide to snakes in Pennsylvania, and is treated as a species of conservation concern rather than a listed threatened species.

Why have timber rattlesnakes declined?

Timber rattlesnakes once lived across most of the hilly, forested Northeast. Their decline has several causes, most of them human.

• Persecution. For centuries, people killed rattlesnakes on sight and at their dens. In northern New York, some counties paid bounties for rattles until the practice was outlawed in 1971. New York’s timber rattlesnake numbers fell by an estimated 50–75%, and the snakes are gone from about a quarter of the state’s historically known dens.
• Habitat loss. Housing, roads and other development have replaced forest and cut off dens from summer hunting grounds.
• Roads. Snakes migrating between dens and summer ranges are often killed crossing roads.
• Illegal collecting. Despite state bans, poachers still take timber rattlesnakes for the black-market pet trade.
• Disturbance. Repeated visits by hikers, climbers and curious onlookers can disturb snakes at dens and basking sites.
• Disease and isolation. Snake fungal disease, a skin infection, has been found in several northeastern populations. In New Hampshire, the last known population is small and genetically isolated, which makes it vulnerable to inbreeding and disease.

Why slow breeding makes recovery hard

Timber rattlesnakes reproduce more slowly than almost any other North American snake. Females take about 5 to 13 years to mature, and a long-term study in New York’s Adirondack Mountains found an average age at first birth of nearly 10 years. After that, a female gives birth only every three to five years, to a litter of about 4 to 14 young, many of which do not survive their first year.

As a result, a population depends heavily on the survival of its adult females. Killing or collecting even a few of them can push a small, isolated population into decline, and recovery can take decades. This is why den protection is so important: most snakes spend the winter in shared dens and return to the same den every year, as explained in Where do timber rattlesnakes spend the winter?.

How timber rattlesnakes are protected

In states where the species is listed, it is generally illegal to kill, collect, harass or possess timber rattlesnakes. Massachusetts, for example, protects the snake as endangered under state law, and New York prohibits collecting it from the wild.

Conservation work focuses on the dens and their surroundings. State biologists survey known dens, estimate population sizes, check whether females are reproducing and study the effects of snake fungal disease. In some places, managers keep basking and birthing sites open by removing trees that shade them, and work with landowners and land trusts to protect forest around dens. Public education is a big part of the effort, since fear of rattlesnakes still leads some people to kill them.

Timber rattlesnakes are part of a much larger picture of reptiles that are secure globally but vanishing locally. You can compare them with species in danger worldwide in our list of endangered animals.

What to do if you see a timber rattlesnake

Seeing a timber rattlesnake in the wild is a rare and lucky experience in much of its range. Stay calm, keep at least 2 m (6 ft) away and let the snake move off on its own. Never try to catch, move or kill it; in many states that is against the law, and most bites happen when people handle snakes. Many state wildlife agencies welcome sighting reports, which help them track populations.

If anyone is bitten, call 911 or seek emergency medical help immediately.