Lizard Lips

 This is my little sister Lila Jane and I a few years ago playing put-put.  Shes adorable.  The course has all kinds of castles and pirates, but Lila's favorite are the giant lizards.  

Some adorable photos..

 

 And now some science.  

Did you know that lizards don't have lips?

 

 Nope, no lips.  This lucky lizard was getting lots of love from a sweet little mammal, but giving none in return.  Why don't lizards have lips?  Well, they don't really need lips.  But lets start at the beginning.

Lizards are reptiles, and they have been around for approximately 350 million years.  The Mesozoic is known as the Age of Reptiles for good reason.  Dinosaurs dominated the terrestrial environment, but the transition from aquatic amphibious individuals to fully terrestrial reptiles required many physiological changes in the preceding era, the Paleozoic.  If you want to be on land, but will dry out, it would be most advantageous to have skin that is more thick and keratinized scales to keep your insides moist and protected from harmful UV rays.  If you want to have your babies on land, and not in the water, you'll need a system to keep them safe while they develop.  Eggs!  If you don't want to be hungry, you'll need to have the tools necessary to capture prey.  This is where we get into the lip-less neck of the woods.

Reptiles are ancestrally carnivorous.  They capture prey animals, crush, gobble, and swallow.  They have no need to manipulate their prey items in a particular manner in their mouth to aid in digestion, like how many mammals need to finely macerate food before ingestion so the stomach can effectively digest the nutrients.  Reptiles have never needed to be able to use their mouths in the same way that we do.  Which is why they don't have lips like we do.

Mammals have lips to strip leaves off branches, eat delicate parts of fruits, remove meat from bone, and to blow bubbles.  That last part is just us I suppose, but the idea of lips evolving to aid in specific functions for like groups of animals was a mind blowing revelation I had the other day.  Lizards don't have lips, neither do turtles, salamanders, frogs, snakes, birds (relatively obvious) or even mammals like rodents.  It's interesting to grasp characteristics that unite us with our animal bretherin like vertebrae, and strange to understand how different we are by thinking about one little thing like lips.

Lizards can smile though.  Just no kissing, or blowing bubbles.