Back Up, Man!

By Cody Noonan

A ratsnake secretes foul-smelling musk from its vent. Photo: Alida Lemieux.

It has been said time and time again that Gray Ratsnakes pose no danger to humans. But just like anything else, the ratsnake will protect itself from perceived threats, and it has some very unique and sneaky ways of doing so.

When you encounter a Gray Ratsnake in the wild, it will most likely do its best to get away from you. In the event that it becomes cornered, it has a few tricks up its sleeve.  The first defence is its posture. The snake may coil up and ‘stand’ on the back part of its body, making it appear larger and more frightening. From this
position it does something that a lot of animals do: mimic something more dangerous and deadly. The ratsnake will vibrate its tail very quickly on dry grass or leaves, making a noise similar to the rattle of a rattlesnake. Whether or not it’s consciously mimicking a rattlesnake doesn’t matter.  The fact that many people, and likely many other animals, have come to associate that sound with danger seems to work for the ratsnake. How does that saying go, “even if you can’t, pretend you can”? Something like that, anyway! But remember the Gray Ratsnake is not venomous, so don’t let the rattle noise fool you like it may fool predators.

Now if these defences don’t prove to be very effective, a provoked snake may turn to other method of protection: musking. Snake musk is a gooey, cream-coloured substance that the snake may ooze out of its vent (cloaca, or rear-end), and like mostthings that come out of an animal’s rear-end, it stinks! The liquid produces a stench that fills the air, and warns any predator, “I’m telling you, I taste as bad as I smell, so you may want to stay back!” Gabriel Blouin-Demers conducted a
study about sexual dimorphism (the differences between males and females of a species) in Gray Ratsnakes. After his research was done, he concluded that the only real difference between the genders was their reliance on musk as a defence. He concluded that gravid (pregnant) female snakes have a musk that is far more pungent smelling than males’, and that these females use musk as a defence more often than males do. It makes complete sense: I’m sure it’s probably hard for a pregnant woman of any species to stand up on her behind and vibrate her bottom on the grass!

Even though they aren’t dangerous, Gray Ratsnakes are still wild animals and just like any other creature they’re most likely going to try to protect themselves. Imagine if you picked up a cute and cuddly wild Cottontail Rabbit: just see if it doesn’t try to bite or scratch you (kids, don’t try this at home)!  Either way ratsnakes are creatures that have some great ways of keeping predators and humans at bay, so be prepared next time you take a closer look at one of these animals.  If it starts to get a little agitated, you may just want to take a few steps back and admire it from a distance.  Otherwise, you may be in for one smelly surprise!

To learn more about sexual dimorphism in Gray Ratsnakes visit http://mysite.science.uottawa.ca/gblouin/publications/003_2000_brs_nws_musk.pdf

The Girl Every Guy is After

By Megan Clark

Lady Gray Ratsnakes are never short of attention from their male counterparts. A polyandrous species, females tend to mate with multiple males. A study published in 2005 found that out of 34 clutches of ratsnake eggs studied, a whopping 88% of them were sired by multiple snakes, some with three fathers to one clutch! Baby snakes hatch amongst step-brothers and step-sisters, oblivious to the
mating rituals that brought them into this world.

In April or May the Gray Ratsnake emerges from its over-wintering site, or hibernaculum, and the population disperses. The fun begins a month later when mating season begins. Unlike some snakes who take part in a “mating ball,” where 50 snakes or more may gather to mate all at once, the Gray Ratsnake female mates with one male at a time. Macho males put on the moves through a ritual “combat dance” and tail-tangling with other males. The winner, of course, gets the girl. But if she’s already chosen the biggest and best male, why mate again? It seems the female ratsnake has her reasons…

Ratsnake populations are not often especially dense, and so although populations from different hibernacula overlap, a female still runs the risk of mating with a male from her own hibernaculum. These males are likely closely related to her. For the sake of genetic diversity it is better for her to mate with a distantly related male. Mating with many makes this more likely. Multiple mating is also good insurance against infertile males or sperm that are incompatible with her eggs. Indeed her strategy does work: more eggs successfully hatch when multiple males have fertilized a clutch.

To read more about this study, visit http://mysite.science.uottawa.ca/gblouin/publications.html#Y2005
and http://mysite.science.uottawa.ca/gblouin/publications/022_2005_brs_sex_selection.pdf

Snake Senses

By Hayley Murray

A snake’s senses are crucial for its survival in the wild. Snakes use their tongues for tasting, touching and smelling. They have very sensitive jaw muscles and are able to detect vibrations from their surroundings: an interesting alternative to external ears! Snakes use their eyes to see but sight is certainly not their best sense.

Gray Ratsnakes, just like other snakes don’t use their noses to pick up scents but instead use something called the Jacobson’s organ. The Jacobson’s organ is also known as the vomeronasal organ. It is located on the roof of the snake’s mouth. As the snake’s tongue rapidly flicks out of its mouth, it captures scent particles from the air. The snake then brings its tongue back into its mouth where it comes into contact with the Jacobson’s organ. The Jacobson’s organ’s sensory cells send chemical information from the scent particles to the brain. This helps the ratsnake to tell the difference between (and respond accordingly to) a potential rodent dinner or a threatening coyote.

Most people think that snakes don’t have ears, but that is not the case. They do have ears, just not external “ear flaps” (pinnae). A snake’s inner ear picks up vibrations from the jaw. How does this work? For example, vibrations from the step of an approaching human are picked up by the quadrate bone (where the lower jaw and the skull join), and are then transferred to the middle ear bone and finally the inner ear. This then allows the snake to “hear” you coming even before you can see it.

Snakes’ senses are what keep them alert and ready at all times. We can all do our part to help these snakes out by letting them go on their way when we see them. These snakes are harmless to humans so there is no reason to be scared of them.

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:
http://mysite.science.uottawa.ca/gblouin/publications.html

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: http://mysite.science.uottowa.ca/gblouin/publications.html

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!

Welcome!

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.