When I was a boy, I used to catch eastern fence lizards and five-line skinks. I never knew the proper name of the former species.
In West Virginia, they are always called “hell hogs,” which, in my estimation, is far cooler name than “eastern fence lizard.”
The fence lizards are in the suborder Iguania, and they superficially resemble their distant iguana cousins. They even do that head bobbing behavior that iguanas do.
I was always fascinated by iguanas. They were like giant hell hogs, and when I learned that there were iguanas on the Galapagos Islands that actually went into the sea to eat algae, I was utterly amazed.
These were real sea lizards!
What I didn’t know at the time is that the marine iguanas weren’t the first lizards to go into the sea.
The truth is that millions of years ago, there were lizards that were adapted to an entirely marine existence.
As a kid, I didn’t know this.
I thought that dinosaurs actually were large lizards, and all my toy dinosaurs had legs that bowed out like those of a monitor lizard.
One of the sad things about the popular conception of dinosaurs is that we think that name, which means “terrible lizard,” actually means that these animals were lizards.
The truth is that all dinosaurs are more closely related to birds than they are to the little fence lizards of my youth. Some dinosaurs are even closer to birds than that, and now, if we are to classify them systematically, we have to consider birds a subset of dinosaurs. Their technical name is “avian theropod dinosaurs.”
I was somewhat crestfallen when I found this out.
That meant that the only amazing lizards were marine iguanas and my other favorite species, the komodo dragon.
What I didn’t know is that there were actually lizards that were every bit as amazing as any dinosaurs.
And you have to forgive my ignorance here.
I actually didn’t know about the marine lizards known as mosasaurs until about three or four years ago.
When I found out that these truly marine lizards existed, I was elated.
The animal depicted above is Platecarpus. It was a highly derive mosasaur that was once common in the Western Interior Seaway that divided North America into two land masses during the Late Cretaceous.
There is a strong suggestion that its tail bent down and a caudal fin was attached to the bend to make a shark-like tail.
And it was basically a 14-foot shark lizard that lived around 80-85 million years ago. A recent study revealed that it even swam much like a shark, which means it would have been one of the fiercest predators in the seas of its time.
Mosasaurs evolved from an archaic varanoid lizards called aigialosaurids, but this is, of course, hotly contested. Aigialosaurids looked an awful lot like modern monitor lizards, and it has been the recent fashion to count mosasaurs as varanoids. Currently, there is a lot of debate over what’s a varanoid. Some authorities count snakes as a type of highly derived varanoid, and if we count snakes as lizards, then sea snakes are also marine lizards.
But there isn’t a sea snake that is anything like a shark.
Evolution is one of the most amazing facts I’ve come to understand.
When I was a kid, my grandmother would keep little chicks from her laying hens in boxes next to her wood-burning stove. In the early spring, the hens would sometimes get too far ahead of themselves and lay eggs before the spring frosts topped, and very often, the chicks would be exposed to the elements and would die. My grandmother always brought those early spring chicks in, and they would be kept warm by the fire.
I didn’t know that these fragile little fuzzballs were actually more closely related to the Tyrannosaurus than they were to anything else living on the planet at the time.
And I didn’t know that the little lizards I used to hold in my hands and put in mason jars and homemade enclosures once were related to beasts that once rivaled sharks in the ancient seas.
Evolution is one of the most amazing facts you’ll ever understand,.
It will humble you, and it will make you look at the natural world in ways that you never thought possible.
That’s why I want people to understand it.
When I found out exactly what it was about, it was one of the most liberating experiences of my life.
And it really stimulated my imagination.
I know that I won’t look at a common fence lizard without the idea of a mosasaur coming up in the back of my mind.
I will marvel at that little lizard.
Not a mosasaur.
But a cousin of sorts.








When I was a kid I thought all the Mosasaurs and Plesiosaurs were sea-gong dinosaurs. I too was shocked to learn that they weren’t.
Anyone who is not amazed & astounded by evolution doesn’t actually understand it.
Maybe the Galapagos Iguanas are on their evolutionary path to being fully marine bound again in a few million years?
I have been fascinated with dinosaurs from a very young age. My mum was quite disappointed that rather than dollies and other girly toys, I was all art, Lego and dinosaurs. I even hogged the TV for documentaries on anything that ever breathed and anything at all to do with evolution and cosmology. I still can’t get enough of the documentaries 4 decades on. Some of the depictions of dinosaurs were hilariously inaccurate! Lizard bowed legs on stegosaurus, kangaroo style tyrannosaurs – all sorts! Some of it actually being scientifically accepted at the time. We’ve come so far in just my lifetime.
I must admit that I never made any connection with lizards and dinosaurs other than them both being reptiles. Back them I just saw lizards as all being tiny little things and birds were just birds and a totally different thing like mammals were. It’s funny the assumptions and ideas you get as a child trying to fit so much in your head in one go. Saying that, the whole bird dinosaur thing wasn’t even a commonly accepted hypothesis in the 70s. It was thought they came from reptiles like mammals did, but on a totally different evolutionary line to dinosaurs. It seems to obvious now!
Oh, the magical, mythical Komodo! These are my faviourite reptile of all. Fair enough, I was glad there was a piece of glass between us, but Trooper and I “shared a lizard/human moment” as we looked each other in the eye from about 3 feet apart. I have no idea what he was thinking (probably “yummy!”), but he definitely had something going on behind those surprisingly expressive eyes. He had an undeniable spark of intelligence and great presence about him which I can’t explain in mere words. It was far more like looking a mammal in the eye than I ever expected. Flora the female was basking at the other end and when I walked round to look at her, she just gave me a dismissive glance and carried on basking with closed eyes. I got the feeling she’s not as interested in the human floorshow as Trooper is. Mind you, she’s a very interesting lady http://www.guardian.co.uk/science/2006/dec/21/uknews and when I was there one of her hatchling sons was on display in his own display so he didn’t get eaten by the big ones.