Nature Notes

Slender Glass Lizard

One of the most unique and interesting residents of the dry open prairies and savannas of Kankakee Sands are the western slender glass lizards (Ophiasaurus attenuates attenuates).  Often mistaken for snakes, these legless lizards are actually quite different from snakes.  They have moveable eyelids and external ear openings!  This may not seem like a huge difference, but it really is.  When you look at lizards, maybe a gecko or the bearded dragon you find in a pet store, one of the first things you see are their eyes…blinking eyes.  The fact that lizards have external ear openings and snakes don’t may not have occurred to you in the past, but next time you see a lizard or snake (or a picture), look a little more closely and you’ll see it. 

Glass lizards differ from snakes in other ways too. Unlike snakes, they are not able to unhinge their jaws.  This means they are unable to eat prey larger than themselves.  No pocket gophers for the slender glass lizard!  These guys generally eat spiders, beetles, crickets, and small vertebrates.  They are also quite stiff and brittle, as opposed to the flexible, more elastic snakes.   The stiff bodies of glass lizards are due to osteoderms (bony deposits forming scales or plates) beneath their skin. 

The name ‘glass lizard’ comes from a characteristic fairly unique to these little creatures.  As a defense mechanism against attack, glass lizards will shed their tails.  The breakage occurs along fracture planes, which allow the tail to splinter into multiple pieces.  Their tails will grow back, but they will not be as long, and tend to grow back darker in color.  Most glass lizards you may have the luck of encountering, will probably have already lost part of their tail.  Western slender glass lizards can reach a length of 42” from head to the tip of their tail; however it is much more common to see them less that 24” long. 

The western slender glass lizard is found from Southern Wisconsin to Texas, and as west as Kansas.  Living in dry prairies and dry open woodlands and savannas, the biggest threat to this species has been habitat destruction and fragmentation.  Listed as an endangered species in some states, including Wisconsin and Kansas, we are lucky here in Northwest Indiana to still have the opportunity to run across these unique lizards. 

One more way these lizards are different from snakes is that you will rarely find glass lizards on roads.  While snakes will often try and cross roads, glass lizards use mode of locomotion that is not conducive to pavement.  They use a side-to-side motion, more like that of a fish swimming through water.  Roads and pavement do not provide the necessary friction to make movement easy.  This is also the reason habitat fragmentation is so destructive for the glass lizard.  They can’t simply move to better habitat across the road.  -Andrea Locke

If you do happen across one of these glass lizards, please remember that they are a bit skittish and breakable, so please don’t try and handle them.