Timber Rattlesnake Telemetry in Connecticut

Timber Rattlesnakes - Part of Connecticut's Natural Heritage

There are few animals in Connecticut that evoke such a broad range of reactions as the timber rattlesnake. This species inspires awe, fear, curiosity, disgust, fascination, or oscillating combinations of each. While most people will never see a wild rattlesnake in Connecticut and experience the aforementioned reactions in real-time, these snakes are native to the state and still persist in several small, isolated populations.

The timber rattlesnake is a large, heavy-bodied venomous snake native to much of the eastern United States. It is a member of the pit viper family, meaning it possesses two small, heat-sensitive openings - one near each nostril - that aid in detecting prey. Adults are typically about three feet long, with some individuals growing nearly four feet in length. Black, gray, yellow, and brown are all various color morphs observed in this species (yellow and black color morph pictured here). Their coloration and skin pattern, which typically feature a series of chevron stripes, equip them with excellent camouflage to hide from both prey and potential predators.

The timber rattlesnake is the only snake listed as endangered in Connecticut’s Endangered Species Act. While these snakes once ranged throughout much of the state, their numbers have significantly dwindled since European settlement. Destruction of their preferred habitat of rocky, forested areas for human development and intentional killing have greatly contributed to the decline of the species. Rattlesnakes serve vital ecosystem roles as both predators and prey. They help balance populations of small mammals (and the disease-carrying ticks often attached to these mammals) but can also be consumed by animals such as hawks, owls, and carnivorous mammals. For all of these reasons, the DEEP Wildlife Division is interested in conserving and protecting this species.

Methods of Study

DEEP staff and collaborators initiated a radio telemetry project in spring 2024 focused on timber rattlesnakes in Connecticut. This project will continue through the end of the 2025 field season. Typically, 6 to10 snakes are tracked throughout the active season (April through October). An effort is made to include a mix of gravid (pregnant) females, non-gravid females, and males. Each sex class usually differs in how they move about the landscape. After snakes are outfitted with a small radio transmitter, project personnel use a handheld antenna and receiver to locate each snake twice weekly (pictured here). Once located, data are collected on the snake’s behavior, its GPS location, and the surrounding habitat. Data are later mapped using ArcGIS software, and seasonal activity range polygons (essentially home ranges) are generated for each snake. Mapping all snake movements together gives a profile of overall landscape and habitat use at the study site.

Goals

This telemetry project has several objectives. While knowledge exists on timber rattlesnake ecology (including seasonal behavior) for many of Connecticut’s populations, this project will provide extensive fine-scale, site-specific information. For instance, insight into any unknown den locations, including satellite (secondary, smaller) den locations can be gleaned from direct observations through this work. This research also provides substantial direct data on how far and how often rattlesnakes move. Rattlesnakes can behave in different ways in various parts of their range, or even in different populations within the same state. Findings from this study will add to the site-specific knowledge base of this unique species. Doing so benefits the DEEP Natural Diversity Database Program in assessing any relevant project reviews. It also helps the Wildlife Diversity Program and collaborators with any data-informed habitat management needs that benefit timber rattlesnakes. Lastly, this information aids DEEP’s Environmental Conservation Police, who are instrumental in addressing any illegal activity (e.g., poaching, intentional killing) related to this protected snake. In summary, this project will help protect rattlesnakes and their habitat in Connecticut.

Interesting Findings

A number of interesting anecdotes have been provided throughout the project thus far. As expected, some snakes move far and wide. The snakes outfitted with transmitters represent a comparatively small snapshot of the overall snake population. Nevertheless, these snakes used most areas of the study site. The takeaway - if habitat is contiguous and protected, snakes will make use of it. Consistent with other studies, gravid females yielded the smallest activity ranges and moved the least often, non-gravid females moved more frequently and farther, and males overall moved the most.

It is interesting to note that each snake has its own “personality”. For instance, one male tracked in both 2024 and 2025 visited very similar areas of the study site in both years. This is also consistent with behavior observed in many animals, including rattlesnakes. As animals find places to eat, mate, and overwinter - in other words, places that benefit their own and the next generation’s survival - they mentally note that positive interaction and revisit the same area year after year in hopes of replicating that positive experience.

Even within a sex class, there is individual variability. For example, some males move father than other males, and the same goes for females. Most of the longest-ranging snakes can be found up to two miles from their den in the heat of summer and may move up to a quarter of a mile occasionally between tracking days. One particularly mobile snake in this study has been found almost three miles from its den and frequently moves more than a half mile at a time between tracking days. Not bad for an animal that slithers over mountains.

While tracking, project personnel often observe behavior that is not necessarily unusual for snakes but is simply rare for humans to see. For example, in 2024, one snake was seen over four feet off the ground in the branches of a tree. This female was very likely hunting for birds, chipmunks, or squirrels. And, in 2025, a telemetered male was observed mating with a non-telemetered female. Though infrequently observed, these observations help paint a picture of the snake population’s overall behavior and health.

At the end of October 2025, as the snakes prepare for winter, DEEP staff will begin analyzing two years’ worth of telemetry data. This information will lead to data-driven, targeted habitat recommendations and law enforcement monitoring at the study site.

What to Do if You See a Rattlesnake

If you encounter a timber rattlesnake, observe it from a distance, calmly and slowly back away from it, and allow the snake to go on its way. Quick movements often scare snakes and may provoke a defensive strike. You should not try to agitate the snake by getting too close or handling it. Rattlesnakes will usually let you know if you are getting too close. All snakes will retreat from humans if given a chance.

Do NOT attempt to kill any rattlesnakes under any circumstances as this is an illegal action. Timber rattlesnakes are protected by Connecticut's Endangered Species Act and persons who kill or collect this endangered snake could be faced with fines or legal action. If you see or know of any suspicious or neglectful activity directed towards timber rattlesnakes, you can report violators to the DEEP's 24-hour Dispatch Center at 860-424-3333.

Acknowledgements

We are grateful to all personnel involved at any stage of this project, including baseline species data collection, planning, ensuring safety, long days of telemetry, and habitat management.

Want to learn more about Connecticut's reptiles and amphibians? Check out the Conservation of Amphibians and Reptiles in Connecticut.

Content last updated August 19, 2025.