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Predator and prey: an intial post

Posted by: Editor on 5/2/2011
Cobra vs. Mongoose
We thought we’d write a quick post on predator and prey interactions as the subject relates to snakes. We find the topic particularly interesting, for in many cases it is the interaction between predators and prey that drives evolutionary development forward. This post only touches on the topic, and we plan to return to the subject in greater detail going forward on a recurring basis. Our intention is to use this post as a baseline from which to launch into a greater exploration of the multitude of predator and prey interactions as related to snakes in the future. If it sounds like a topic you’d like to delve into further, then by all means read on.
To start with, we think we can all agree that snakes have been incredibly successful from an evolutionary perspective. After all, there are snake species on every continent except Antarctica, which suggests that collectively they’ve been well suited to Darwin’s game of survival of the fittest, adapting to all but the coldest and harshest habitats. One of the reasons we find snakes so interesting is that they’ve developed a number of survival techniques to minimize the risks they take as they pursue a successful existence on planet earth. At HVH we think this policy of risk minimization puts one in a position to get “lucky,” and it’s in “getting lucky” that ultimate success in the game of life lies.
To start with, let’s operate on the assumption that it’s not good for anyone or anything to be found by a predator. Hence we can perhaps say that rule number one in the game of life as it pertains to dealing with potential predators is: “don’t be found.” Snakes have developed a number of innovative strategies at avoiding detection that have essentially served to minimize exposure to potential predators, some of which we’ll explore in further detail in this post. Second and closely related to rule #1, we can agree that probably the next most important rule is that if you see someone coming, get out of dodge fast! i.e., if you see or feel a predator nearby, escape as quickly as possible.   Snakes are good at vanishing from situations that involve potential danger, and it’s one of the reasons they have been so successful.
Rule three applies to the case of discovery by a predator: “if you’re found, make sure you’re left alone.” In essence, if a predator finds you, make sure they think you’re something you’re not – something not particularly suited to predation. There are a number of examples of mimicry in the snake world that serve as illustrations of this rule. The final rule for avoiding predation and successfully passing your genes onto the next generation: “if spotted by a predator and identified, have a way to fight and get away before being eaten!” 
So in summary of our rules, our take is that there are four critical aspects to successfully avoiding predation:
First, don’t be found.
Second, if discovery is imminent, run away.
Third, if found, make sure you’re left alone by convincing the potential predator that you’re not worth the effort or risk of predation.
Fourth, if found and your discoverer decides that he or she wants to eat you, have a way to fight back and avoid being eaten.
Snakes, in one way or another, are masters at all four of these strategies, and it’s because of this mastery that they have been so successful at avoiding predation and passing their genes onto subsequent generations. There is much to be gained from an in-depth analysis of the solutions snakes have come up with to each of these four conundrums. We only include brief examples of each of these four strategies in this post, but plan to dig much deeper on a case by case basis in future posts. We hope to learn something from our investigations, and hope that our readers also find something of value.
Heron captures snake
Avoidance. That’s the essence of rule #1. To avoid detection you pretty much have two options – first, try not to be around when your potential predators are active. If your predators are diurnal (active and hunt during the day), you better be nocturnal (active a night while your predators are sleeping). Many snakes are nocturnal, protecting them from predation from diurnal bird species. We know from experience that many of the snakes we keep are very active at night, but hide during the day. This is no accident. Distant relatives of the snakes we keep that tried to hunt during the day were far more likely to be victims of predation than their brothers and sisters who laid low until sundown. Other snakes, like the Gaboon Viper, can lie still in the brush of the forest floor, perfectly camouflaged in the leaves and twigs on the ground, thereby avoiding detection. There are many other snakes that blend perfectly into their surroundings to avoid detection, even in plain sight.
Gaboon Viper in brush
Run away. Snakes whenever possible take the approach of the gallant knights in Monty Python’s Holy Grail when faced with the vicious Rabbit of Caerbannog – they run away! Snakes are actually quite vulnerable. They have no limbs so they have to take a pass on hand to hand combat. Their bites, aside from those from select venomous species, are relatively mild, teeth small and for the most part harmless. Their slender, elongate bodies often lie defenseless and exposed, and their condition as ectotherms limits the environmental conditions in which they can effectively be active. Overall, then, it makes sense that snakes are quite careful with the risks they choose to take. For this reason, it is very rare to find a snake in the wild, and if you do happen to see one it will usually dart into a borough or beneath a pile of rocks before you can get too close. 
Don’t tread on me. Yes, this was a phrase that appeared on some early flags of the United States that also carried a picture of a rattlesnake. It’s a good paraphrase for Rule #3 – if you’re discovered, hopefully you have a mechanism to convince your would be predator to leave you alone. Perhaps you are a milk snake that mimics the color pattern of the coral snake, thereby warning potential predators that you are venomous, even though you are not. This warns predators that the cost of trying to eat you (a potential venomous bite) is not worth the effort required to eat you. 
Hognose feigns death
Some snakes, like the hognose snake, have multiple mechanisms for convincing predators to leave them alone – when right side up the hognose snake in many respects mimics a poisonous viper, thereby scaring predators away. In addition, if faced with a severe threat, the hognose snake will roll onto its back and play dead, thereby making it less desirable to many predators looking for a fresh meal. For good measure, it will also release a potent and foul smelling musk from its vent to add an additional dissuasion to the predator in question.
Fight. If discovered by a predator intent on eating you, you have nothing to lose by fighting back. Many snakes have developed mechanisms to fight with potential predators. This can range from hissing and striking at potential threats (snakes have been known to successfully hold off large predators by hissing and striking wildly) to biting and envenoming attackers. There are many species of snake that can easily kill large mammals with just a pinhead of venom. 
Investigating the inter-relationships between predator and prey is an extraordinarily complex undertaking.  It involves not just the primary actors – the predator and prey – but all the variables of the environment in which they live (other animals, temperatures, etc.). There is a large body of academic research outlining predator and prey relationships among reptiles and amphibians, but there is yet a long way to go. Part of the time we spend on this blog will be devoted to exploring these issues in more detail, using real world examples of predator and prey interaction to help us understand the competitive dynamics of the ecosystems in which snakes are an integral part. More to come soon!
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