Natural History

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.