Snakes. From the Bible to pop culture, snakes are perceived as cold and soulless creatures slithering from one prey to the next. Not only do they lack the common decency to walk on legs, but they prey on small birds, our cute mammalian relatives, and even in some cases, humans. The idea of a snake being a good, wholesome, altruistic creature seems so contrary to everything we know about them. So how unlikely is it that a member of this sub-order actually contains some of the most dedicated moms in the animal kingdom? One scientific study out of France suggests that one species of snake might hold the new standard of motherly love. Step aside tiger moms, there is a new queen of the animal kingdom.
Snakes are cold-blooded animals, which means they are incapable of internally maintaining their temperature. To make up for this lack of internal temperature regulation, most reptiles bask in the sun to attain an ideal body temperature. During pregnancy, this thermoregulating behavior is increased as it is thought to increase the developmental rate of the offspring within the mother[1]. However, basking can increase the likelihood of predation on the mother, as many hiding places are hidden away from not only predators, but also the sun[2]. By hiding within a shaded refuge, a pregnant snake increases the likelihood of survival, but also takes the snake out of the ideal temperature potentially decreasing the development of the offspring. In 2012, A research group led by Sophie Lorioux tested the dedication of the aspic viper (Vipera aspis) to its offspring by measuring the amount of time pregnant vipers displayed the basking behavior when presented with possible threats. Would the expectant mothers run to save their own lives, or continue basking and increase the well-being for their children?
In order to test the vipers’ thermoregulation behavior, the researchers placed thermometers into the snakes’ stomachs. They monitored both pregnant and non-pregnant vipers in an enclosed space throughout the duration of the snake’s pregnancy. Some vipers from both the non-pregnant and pregnant groups were exposed to simulated predator attacks performed by the researchers. The vipers were provided a hiding area, however it was located away from a light source forcing the snake to either continue the basking behavior, or interrupt thermoregulation by hiding from the predatory attack. The researchers found that pregnancy had a very significant impact on the amount of time the viper spent basking, even when exposed to predatory attacks. Not only that, but there was also no significant difference between the amount of time pregnant females exposed to simulated predatory attacks spent thermoregulating as opposed to pregnant females who were not exposed to predation. Most pregnant females would only allow for a “small decrease in body temperature before emerging (from hiding) as compared with non-reproductive ones”[3]. This preference of temperature regulation did not change throughout the pregnancy as previously thought[4].
The results of this study support the idea that this species of snake will risk its life for the development of its offspring during pregnancy, but does this prove dedication to the offspring? There are other tactics that this species of viper relies heavily upon such as camouflage and venom. The aspic viper may never have to actually hide by compensating using these other tactics. Another hypothesis states that keeping a constant temperature during pregnancy may increase offspring viability and speed up the developmental process. In other words, staying at a constant temperature could potentially make better babies and speed up the pregnancy process. Whether or not this truly altruistic behavior is impossible to say. But we do know that there is some steep competition in the animal kingdom for who reigns as “Best Mom”.
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Alicia Bukowski
October 10, 2017 — 6:33 pm
Typically we don’t think of snakes as exhibit much, if any, parental care. Now pre-pregnancy care isn’t technically parental, but it definitely is more dedication that I’d expect! I’d look forward to more research into snake’s investment in their offspring.
Gabrielle Moore
October 12, 2017 — 12:54 pm
I found this article to be interesting. The title caught my attention, and I was not disappointed. Typically, when we think of animals taking special care of their young, we think of mammals. The snake especially doesn’t come to most people’s minds. So, I enjoyed reading about how pregnant snakes of this species have left themselves in harm’s way long enough for their offspring to benefit. I’m not very familiar with this species, so I think it would be interesting to see how this snake interacts with its young after birth (if there is interaction).
Hamda Hussein
October 12, 2017 — 2:36 pm
This was an interesting article despite being terrified of snakes. It was surprising to read that snakes show parental care instincts. it would be interesting to see if also the males show care for their offspring or if it is solely mothers thing.