a few interesting things about serpents
Miss Nebet, a spotted python (Antaresia maculosa) who will be serving as our live model for today.
many of these are probably well-known; others have surprised even other snake owners.
Snakes (suborder Serpentes) are lizards (belonging to order Squamata). Snakes are no longer thought to be a group outside of all other lizards; snakes are more closely related to iguanas than iguanas are to geckos, for example. The closest living relatives of snakes are Iguania (for example iguanas, chameleons, and dragons) and Anguimorpha (for example galliwasps, beaded lizards and monitors). Snakes are also relatively closely related to mosasaurs (such as the lovely Platecarpus pictured below), with some proposals suggesting mosasaurs are their closest squamate cousins. The various other legless lizards arise from all across Squamata, and aren't necessarily closely related to eachother or to snakes.
Snakes are almost entirely composed of "torso", with their ribcage extending down the majority (~90%) of their length and only a short neck and tail. The tail begins just after the is usually distinguishable by a slight narrowing and an end to the wide, flat ventral (belly) scales. By contrast, most other legless lizards have long tails making up a large portion of their overall length.
The green bar marks the approximate beginning of the tail, the diagram demonstrates the layout of belly and tail scales in two species. On her request, I have not included an image of Nebet's vent as it would be improper.
Snake ribs are jointed and manipulable, serving a role in movement, constriction and Their flat ventral (belly) scales are independently mobile, and can be raised in sections to create friction or flattened to glide across a surface. Both of these features are lacking in other legless lizards.
Miss Nebet's very cute pink ventral scales.
These unique features allow snakes to use four (conservatively; I have seen categorisations as high as eleven) separate methods of locomotion, combining these different methods in many ways to move across all sorts of surfaces. These methods include lateral undulation, in which the snake exerts muscles all across its body to push against the terrain in a typical serpentine motion, concertina, in which the snake pulls its body into bunches then extends in an accordion-like manner, rectilinear, in which the snake flexes muscles across its length while manipulating its ventral scales to drag itself in a straight line, and sidewinding, in which the snake 'throws' itself at an angle to traverse a slippery surface with little traction. Other legless lizards use simple undulation only, a more basic method of movement involving essentially wriggling in waves.
I have personally seen miss Nebet use all of these methods of locomotion except sidewinding.
Snakes do not 'unhinge' or dislocate their jaws when eating- rather, the lower jaw is split into two halves with a flexible attachment to the skull, allowing them to be independently 'walked' over prey. This allows them to swallow prey items much larger than the size of their head would suggest. Other legless lizards lack this bifurcated jaw, although they typically have very flexible skulls to allow them to swallow larger prey.
An Indian Rock Python (Python molurus) skull demonstrating the bifurcated jaw and Nebet demonstrating its utility in swallowing a mousey.
Snakes possess several unusual sensory organs depending on species. The first is their famous forked tongue. They flick their tongues to collect scents from the air then return it to a special cavity on the roof of their mouth (called the vomeronasal or Jacobson's organ) that allows them to detect chemical information. The fork in their tongue makes the sensing directional. They can also smell 'normally' through their nostrils.
The second of their unusual sensory organs is their heat pits, found in boas, pythons and pit vipers. These special rows of pits on (some) snakes' faces allow them to sense infrared thermal radiation. This adaptation, not found in any other lizard, has evolved independently multiple times across snake species.
Contrary to popular belief, snakes do possess ears and can hear sounds, although they lack visible external ears. They are also sensitive to groundborne vibrations through their jaw. Other legless lizards typically have visible, external ears.
Miss Nebet's forked tongue and heat pits (circled in pink). Scientifically speaking, these can also be referred to as 'charm points'.
These are just a few interesting things about snakes, the most beautiful and lovely vertebrates in the entire world. I haven't even talked about their teeth and fangs, the different kinds of specialised scales they can have, their venom or all sorts of other things. Please say thank you to miss Nebet for taking the time out of her day to have her photo taken for us, and please love and adore all serpents you meet!
