Motherly Instinct

By Alida Lemieux

Gray Ratsnakes, like many other snakes are oviparous, meaning they lay eggs.  Female ratsnakes usually lay a clutch of a dozen or more eggs in late June or July, and abandon them after laying.  While this may not be considered the most caring of parental behaviours, ratsnake mothers apparently make some important decisions when it comes to selecting a nest site.

An ideal nest could be a rotted stump or log, or a burrow beneath a rock pile or leaf litter.  Many wild ratsnakes choose to nest communally, which makes for a warmer nest temperature and increases the young ratsnakes’ chances for survival.  Hatchlings from warmer nests tend to hatch earlier, grow longer, and swim faster!  Here, at the northern limit of the Gray Ratsnake’s range, hatching out quickly (by late August or so) is a major advantage.  An early freeze could kill un-hatched eggs in the nest.  Research conducted in the late 1990s and early 2000s confirmed that, in a lab setting, female ratsnakes still preferred to lay their eggs at temperatures closer to those of communal nests.

A mother’s best intentions could go sour though, thanks to an inconspicuous insect.  The Pustulated Carrion Beetle (Nicrophorus pustulatus) is a parasitoid of the Gray Ratsnake.

Ratsnake eggs parasitized by carrion beetles. Photo: Gabriel Blouin-Demers.

This beetle lays its eggs on those of the ratsnakes, and when the larvae hatch out, they destroy their ratsnake-egg hosts.  When female ratsnakes nest communally, they run the risk of increasing the chances of parasitism by these carrion beetles.

For more information on the effects of nest site selection on young ratsnakes, check out Gabriel Blouin-Demers’ website at:

Posted in black ratsnake, carrion beetles, gray ratsnake, Murphys Point Provincial Park, ratsnake, ratsnake parasite, snake reproduction, snake research, Uncategorized

Warm Enough For Ya?

By Alida Lemieux

Caught May 5th, this Gray Ratsnake probably spent its first winter in a forested Murphys Point campground. Photo: Alida Lemieux.

Spring has finally sprung, and Gray Ratsnakes are emerging from their overwintering sites, or hibernacula.  We humans are “emerging” from our homes as well; ready to take on whatever weird weather and flip-flopping temperatures Nature has to offer us!

Both snakes and humans must thermoregulate, or adjust body temperature, to function properly.  An optimal body temperature of around 28 degrees Celsius (9 degrees cooler than a human’s normal body temperature) helps a Ratsnake to move, eat, digest, mate, or shed efficiently.  While endothermic (warm-blooded) humans thermoregulate by sweating, shivering, or adjusting layers of clothing, ectothermic (cold-blooded) Ratsnakes can only rely on the temperature of their surrounding environment to warm them up or cool them down.  A nice rock or cedar branch often provides a Ratsnake with the perfect spot for soaking up rays on a breezy spring day.  Unlike a die-hard beach bum though, Ratsnakes don’t like to cook themselves!  A hollow tree or rock pile can offer cool comfort during a heat wave.

Interestingly, Gray Ratsnake habitat is connected to thermoregulation.  Adult Ratsnakes in particular need forest edge habitats, which offer quick access to both shade and sun.  A “best of both worlds” habitat means less travel and movement is necessary, which means the snake’s energy can be preserved.  This is particularly helpful to a gravid female (a snake carrying eggs) or a snake who’s just eaten a big meal of chipmunk!  Juvenile Ratsnakes, on the other hand, are just about as likely to be found within forests as they are at forest edges: being smaller, they can thermoregulate and energize themselves more quickly than large adults.

Much of the research on Ratsnake thermoregulation was conducted by Gabriel Blouin-Demers.  For more information, check out his website at:

Posted in black ratsnake, gray ratsnake, Murphys Point Provincial Park, snake research, thermoregulation, Uncategorized

Snake Season

Back in the 1990s, some intensive research took place at Murphys Point Provincial Park. The aim was to track individual Gray Ratsnakes to determine what their habits and ranges were. Snakes were captured and a small radio transmitter device was surgically implanted under their skin. They were then released where they were found.

The transmitters emitted beeps (different frequencies for different snakes) so that biologists and other researchers could tune in and track individuals using a large antenna.  For years they kept journals of the movements of the snakes – where they travelled, basked, laid eggs, ate, shed skin and hibernated. The signal can also be used to determine the snake’s body temperature by matching the rapidity of the beeps to a temperature chart.

The result of this study was that researchers got a pretty good idea of the “ranges” of these snakes and found they are creatures of habit – returning to familiar spots to shed skin, mate and lay eggs, for example. They found each snake appeared to stay within a “home range,” and each range differed for individual snakes. Some preferred wet areas and others higher, drier places. Some liked to hang around in trees, while others liked hollow logs. They also learned the snakes can travel up to one kilometre a day and averaged 100 to 300 metres.

The snakes were also monitored in winter. Researchers would check on them periodically while they hibernated underground, noting locations and temperature with the receiver. Several seconds between each “beep” indicated the snake was cool, and researchers used the chart to determine the exact temperature based on the frequency of the beeps.

With the snakes showing preferences for some of the same places each year, it was determined further development of these areas could disrupt the snake’s habits and be detrimental. The research was particularly valuable for pinpointing locations of hibernacula – places where large groups of Gray Ratsnakes congregate to spend the winter underground. Because Gray Ratsnakes are threatened in the area that includes Murphys Point, knowing these locations helps park staff to protect those areas.

Now there is another new and valuable use for the research collected in the 1990s – education. The Friends of Murphys Point Park have developed this blog as a way to educate people about the Gray Ratsnake and the efforts that are out there to conserve it, but we’re also using social media – Facebook – as a way to describe the life of these snakes. Using the real data collected in the 1990s, we will be posting updates on Facebook to show how an individual snake moved throughout each season. Be sure to log onto Facebook and make friends with Diana Spiloides to follow her activities! Also on Facebook, park naturalist Mike Murphy will be describing the activities from the researchers’ point of view.

The snakes will be emerging from hibernation soon, so stay tuned for regular updates!

Posted in black ratsnake, Murphys Point Provincial Park, snake research, Uncategorized | Tagged , , , , ,


A snake portrait - Murphys Point

Welcome to our Gray Ratsnake blog – a site devoted to answering questions and promoting local conservation efforts for this species at risk in Ontario. Also known as the Black Ratsnake, this harmless constrictor is the subject of provincial recovery efforts. Learn more on these pages. Have a question? Check out our “Ask a Naturalist” page. Want to make a donation to support protection and education efforts? Check the “Donations” page.

Posted in Uncategorized | Tagged , , , | Leave a comment