Best Dramatic Actor: The Eastern Hognose Snake
Here in Wisconsin, almost all our snakes are non-venomous, and rely on deceptive defense measures to scare off potential threats. The eastern hognose is one such snake and has slithered onto center stage in this week’s Wildlife Matters.
Last month I came across an article about eastern hognose snakes that immediately captured my interest. Snakes tend to cause concern and fear in many people, and understandably so. Their appearance, movements, and behavior are entirely different from ours, and from many of the birds and mammals average people enjoy. Eastern hognose snakes will never win any popularity contests, or beauty contests, but they might win awards for best dramatic actor.
Hognose snakes get their name from their upturned snouts, and like hogs, they use them to root around in soft soil in search of food, especially their favorite—toads. They are thick-bodied snakes that can reach lengths of two to four feet, depending on where you are in North America. They can get quite large in Georgia and Florida but are on the smaller end in the northern reaches of their range, up in southern Ontario Canada. In fact, the article I read was focused on a research project that studied these snakes in southern Ontario. There, they are protected as an endangered species whose numbers are dwindling for two main reasons: loss of quality habitat and Ophidiophobia, or fear of snakes.
Hognose snakes are harmless to humans, what we refer to as non-venomous, even though that is only partially true. In fact, they do produce a weak venom that works well on toads but rarely producing more than a minor allergic reaction in humans. They have fangs in the back of their mouths that deflate a puffed-up toad to make it easier to swallow. They will also eat birds, small mammals, invertebrates like worms and bugs, as well as frogs and salamanders, but they heavily favor toads.
If you have never seen a hognose snake, you may not be familiar with their acting skills. When they feel threatened, they puff up with air, then flatten their head and neck similar to how you might imagine a cobra might look with its hood spread. There are two dark spots on the back of this flat area, a deceptive coloration we call eye spots. The snake will hiss and lunge, pretending to strike in defense, but it won’t open its mouth. This is often enough to deter predators, but if the snake doesn’t think they are falling for it, it moves to the main act. It will start to act like it is dying from something painful, writhing and rolling on its back. They will regurgitate their food, defecate on themselves, and emit an unpleasant musky odor. Then they will lay their motionless until they think the danger has passed. You can find plenty of videos of this online on YouTube or Google, and it is worth watching if you haven’t seen it.
The study I read about, in southern Ontario, wanted to understand more about the breeding needs of the population. They implanted radio transmitters in female snakes and followed them for three years outside of hibernation. They found that open sandy areas, in this case sand dunes, were critical for these snakes to nest. They would emerge in spring and breed, becoming sexually mature at two years old. They would all head to a suitable nesting location where they would deposit about 15-25 eggs in a depression in sandy soils under rocks or logs. Then the snakes would disperse, going separate ways until it was time to hibernate. The eggs incubate for about 1 to 2 months when the young emerge and are completely self-sufficient. While sandy soils are important, mature forests with areas of canopy cover and downed trees were desirable to provide cover from predators. If you think about where you find toads, a mixture of open sandy areas and older trees will often produce large numbers of them here in the Northwoods. Finally, and most interesting for me, the three-year tracking study showed that the snakes tended to avoid paved roads, rarely crossing them. I have noticed that fox snakes seem to like pavement, stretching out on the roads to warm up on cold mornings. This avoidance behavior might be one reason why, in my many years in Northern Wisconsin, I have only seen one car-killed hognose. As you might imagine, while a retching and writhing death scene may deter predators, it would not do well to prevent a vehicle strike.