A real mouthful
Greetings from Scaly Slimy Spectacular! Snakes have a serious manner problem nearly every time they eat: they cannot chew with their mouths closed. Not having arms means snakes cannot pull their food apart into more manageable size pieces (with the exceptions of the white-bellied mangrove snake, which breaks crabs apart for easier consumption, and the kukri snake, which has recently been discovered to use its teeth to cut open toads and only eat the organs. And some prey for snakes can be quite the meal – well over 100% of the snake’s mass! The techniques and adaptations snakes utilize to successfully consume prey have possibly even captivated your attention if you have ever seen one of our snake feedings at Zoo Atlanta. While the snakes here at the Zoo are not offered live prey, you can still get a fascinating look at their feeding behavior and biology.
If you are lucky enough to observe a snake feeding here at the Zoo, you will notice an initial step nearly every snake makes before they attempt to eat their food – finding the head. Whether the prey is a rodent, bird, or fish, making sure it goes down head-first is important for success. Legs, wings, and fins naturally lay to the side, which means the best way to compact prey efficiently is by consuming it head-first.
The snake will then begin pulling the food into its mouth – which is a lot easier said than done if you do not have arms and legs! I’ve seen some snakes be particularly crafty with their tactics, using rocks and the ground to help push food into their mouths. However, snakes will typically resort to a method called the Pterygoid Walk. Snakes have highly mobile (i.e., kinetic) skulls – especially their jaws. Their top jaw teeth will ratchet down onto the prey in an alternating “walking” movement, while their bottom jaw does the work on the bottom.
The real magic is that bottom jaw, though. There is a pretty big misconception that snakes can “unhinge” their jaws to maneuver around food. The truth is actually even cooler. The first adaptation is the extra bone on either side of the jaw – the Quadrate Bone. This allows the jaw to extend much wider than their appearance may indicate. The next amazing adaptation is that the lower jaw of snakes is not a single bone. Actually, the lower jaws of humans are not, either – but they are connected at the chin by a bony fusion. The lower jaw bones of snakes are instead connected at the chin by elastic-like tendons (imagine a rubber band). This allows snakes to really open their mouths up to consume massive prey or also give epic yawns!
Here at Zoo Atlanta, we typically give our snakes food items that are about as wide as the widest part of the snake. So maybe you will be able to see some of these neat adaptations and techniques in action on your next visit.
Keeper II, Herpetology