How Did Dinosaurs Sleep?

One question that kids often wonder about is how did dinosaurs sleep? Or did they sleep? For instance, did they sleep standing up or laying down? Did they sleep in caves? Especially intriguing is the question, “How did the tyrannosaurus sleep?” Could a T-Rex lay down and if it did, how in the world would it possibly get up with those tiny ridiculous arms?

There have actually been lots of conversations about these very questions and today I’d like to take time to unpack some of the answers.

QUESTION:
How Did Dinosaurs Sleep?

ANSWER:
Yes, dinosaurs did sleep. But, knowing exactly how they slept, whether they slept standing or laying, is not a question we can answer with certainty. Even though we have some fossils of dinosaurs said to be sleeping, we have to depend mostly on our knowledge of living animal sleeping habits. By looking at Elephants, giraffes, crocodiles, and birds we can make the ‘best guess’ about how dinosaurs might have slept.

 

So it seems pretty obvious that dinosaurs did sleep. After all, just about every animal sleeps. But there are other questions that need to be answered. Like – how did they sleep, when did they sleep, and more? Let’s look at some of those questions now.

 

Did Dinosaurs Sleep Laying Down or Standing up?

Since kids love dinosaurs so much there are several children’s books about dinosaurs and even about dinosaurs going to sleep at night. One such book, “How Do Dinosaurs Go to Sleep?” by Jane Yolen is a fun read for kids at bedtime.

However, it doesn’t answer the questions about how dinosaurs actually sleep. It’s mostly a book about turning out the lights and going to bed without fighting mommy and daddy at bedtime.

We want to know how dinosaurs actually went to sleep. Specifically, did they sleep laying down or standing up.

Now, to answer this question we have to first understand that it is very difficult to know for sure how dinosaurs slept because dinosaur behaviors are very difficult to learn simply from fossils.

We might be able to determine how fast a dinosaur could run by looking at fossil and making calculations based on its weight and gate, etc.

But knowing if dinosaurs cuddled, or slept near each other, or needed 6-8 hours of sleep is almost impossible to know since such things are unobservable.

So what can know about dinosaur sleeping habits?

One thing we can do is observe similar animals that are still alive today. Animals we can free observe may teach us about prehistoric sleeping habits.

By studying Elephants, giraffes, crocodiles, and birds we can make an educated guess about how dinosaurs may have slept many many years ago.

Today’s animals have different sleeping habits depending on size, weight, and especially whether they’re bipedal or quadrupedal. We have several examples of four-legged animals that sleep standing up. horses and giraffes sleep while standing. It’s very difficult for a two-legged animal to sleep standing up. I’ve never tried it, but I imagine it’s hard to keep good balance while you’re sleeping.

 

How sauropods might have slept

 

It is often suggested that the giraffe is a good comparison for a sauropod. Remember, a sauropod is a very large quadrupedal herbivorous dinosaur with a long neck and tail, small head, and massive limbs.

 

 

Take a look at a giraffe. It does have four legs, a long neck, and a small head. And, we know a good bit about a giraffe’s sleep habits.

 

• giraffes sleep standing up
• giraffe’s sleep for a few minutes at a time
• giraffe’s average only 30 minutes a night

Why do giraffes sleep like this?

Because there is always the threat of a lion.

A big giraffe with skinny legs would not want to sleep laying down for 8 hours at a time because a lion could just come along and eat sleeping giraffes all night.

Instead, he sleeps in such a way to be alert and ready to RUN at a moments notice.

A sauropod like an Amargasaurus may have slept very similarly to a giraffe. Standing up, only for short naps, and ready to RUN if a monstrous carnivore should show up.

How would you sleep at night if you knew a carnivorous monster was lurking out your window.

But, it is also very possible that sauropods didn’t sleep standing up. It is also true that giraffes sometimes do sleep laying down.

Babies sleep with their legs pulled in under their warm bodies and their heads rested on top of their comfy stomachs.

If a brontosaurus felt safe in his sleeping quarters he may have slept like just like this:

How quadrupeds might have slept

Perhaps if we studied the sleep habits of cows and elephants we can get a good idea about how triceratops or ankylosaurus might have slept.

Most people think that cows sleep standing up. After all, how else could you go cow tipping if they didn’t? However, cows actually sleep laying down, on their sides, and for up to 14 hours a day! They must be really bored!

Elephants are the same. They sleep lying down and on their sides. Though, they can sleep standing up. Elephants often take naps while standing, but at night, they get down on the ground, lay on their sides, and sleep for 2-3 hours.

So what can we glean from the sleep habits of these four-legged mammals? It’s probably safe to assume that a quadruped dinosaur slept in the same way.

How T-Rex might have slept

Speculating on how a Tyrannosaurus Rex might’ve slept is a bit more interesting. Since it only has two hind legs and two seemingly useless little arms, it is often wondered just how a T-Rex could lay down and especially get back up again.

Since the T-Rex was the apex predator of his time he might have slept like a lion, very comfortably and for long periods of time. Especially after a big brontosaurus steak burger and fries.

 

Interestingly, T-Rex (and the Iguanodon) has what some paleontologists call a third-foot or the ‘pubis’ bone.

It has long been expected that this pubic bone might have been used for the T-Rex to sit and to get back up.

“Sit Rex, Sit. Good boy!”

In a presentation called, “Rex, Sit,” Kent A. Stevens and Eric D. Wills at the University of Oregon animated just how “the great theropod would have settled its weight upon its pubic boot.”

 

Okay, so here are the basic 3 choices we have about how T-Rex slept:

1. Did T-Rex Sleep standing up: I don’t think so. “Let’s go, T-Rex Tipping!”
2. Did T-Rex Sleep sitting down: I like this idea. It seems likely that a T-Rex might “take-a-load off” every once and I while.
3. Did T-Rex Sleep laying down: Most animals do. I think T-Rex, like the lion today. Would sleep very comfortably.

Fossils Found of Dinosaurs Sleeping

There have been a few fossils unearthed that seem to have preserved a dinosaur while sleeping. The most famous and recent of these sleeping dinosaur discoveries is a dino called Mei long.

Mei long is a Chinese phrase meaning “sleeping dragon.” Mei long is a duck sized troodontid dinosaur 1st unearthed by paleontologists in Liaoning, China in 2004. Mei lived during the Early Cretaceous Period.

What’s so special about this dinosaur is that she appears to have been preserved in a sleeping state with her head resting upon her folded arms.

Other dinosaurs fossils that look as though they were sleeping are the Segisaurus, the Sinornithoides, and the Guaibasaurus. Notably, all of these dinosaurs are closely related to birds as well as fossils that resemble the resting posture of birds.

Conclusion

In conclusion, of course, dinosaurs slept. They had too. But, until some amazing future fossil discovery, we can only speculate and wonder. Even then, it will be nearly impossible to determine exactly how they slept. If they slept for 8 hours, or with their eyes opened etc… Until then, I wish you a wonderful night’s sleep as you dream of friendly dinosaur pets 🙂