Science Question From a Toddler: Omnivore Dinosaur


Each month, I pick a question from a current or former toddler and answer it on BoingBoing. If a toddler you know (or once were) has a pressing science-related concern, email me!

Anyone who's watched "Jurassic Park" (and, subsequently, thought up a velociraptor escape plan) knows there were meat-eating dinosaurs. Anyone who's had to talk a child (or themselves) down from a post-"Jurassic Park" nightmare knows that most dinosaurs ate plants. But Pbryden's 4-year-old wants to know whether any dinosaurs ate both.

That sounds like just the kind of thing velociraptors would do to trick you into complacency...

That aside, the idea that a dinosaur would eat both flora and fauna makes a lot of sense. After all, birds evolved from dinosaurs. And plenty of birds are omnivorous. But what birds eat is easy to verify. We can toss a bucket full of varied grub into a pack of chickens and watch as they dine happily on everything from cabbage to, um, chicken. Paleontology doesn't really work that way (thank God). So how do scientists know what dinosaurs ate? They look to the teeth.

Today, animals that eat only plants and animals that eat only meat have very different sorts of teeth. Carnivore teeth tend to be pointy, curved and serrated--good for holding a wriggling victim and ripping through flesh. Herbivores, on the other hand, don't usually have much of an issue with their dinner escaping. Their teeth have a wider variety of shape across species--meat is more of a uniform product than plant life--and within the mouth of a herbivore you'll often find a mix of pointy-but-blunted teeth (for biting off hunks of plant) and some flat teeth (for grinding and chewing the plants). Scientists use these traits to interpret what they see in the mouths of dinosaurs.

It doesn't always work perfectly. For instance, prosauropods---a family of dinosaurs that tended to look sort of like a bi-pedal version of the more familiar long-tailed, long-necked Apatosaurus (nee Brontosaurus)---were once thought to be carnivorous, according to Emory University professor Anthony J. Martin. After all, they had serrated teeth. But later research---based on the teeth of modern plant-eating reptiles---turned up a better theory. Some herbivorous dinos had serrated teeth, but the serrations where different---more course and pointing in different directions---than the serrations on meat-eating teeth. The serrations helped animals like the prosauropods cut through thick, woody vegetation.

Because this is all a bit inexact, there's a lot of debate over whether omnivorous dinosaurs existed. In 2006, Dr. Martin wrote that there wasn't yet any real compelling evidence of omnivorous dino-diets from stomach contents or fossilized poop. Therizinosaurs---a truly weird-looking creature that walked on two legs, had a long neck, and sported a set of front claws that made it look like the improbable love-child of Edward Scissorhands, Wolverine and a sloth---is often cited as an omnivore. But it's actual diet is still unclear. There's a good chance it was just another herbivore or, possibly, an insectivore.

Heterodontosaurus is another possible candidate for the omnivorous dino crown. It's very name means "different-teeth-lizard". It might as well be called, "Wow, that's pretty freakin' weird." Heterodontosaurus has a larger variety of different types of teeth than most other dinosaurs. You'll often hear it compared to human teeth, which feature bitey, grindy and rippy options. Some scientists think that means Heterodontosaurus ate an equally varied diet. Fruitadens haagarorum, for instance, is a raccoon-sized relative of the Heterodontosaurus whose discoverers think probably dined on fruit and insects. Others, however, say that---like the prosauropods---all the heterodontosaurids were likely using their funky teeth to process plants.

The final verdict: If Pbryden's 4-year-old wants a firm answer, he or she may want to consider a career studying fossilized dinosaur poop. This is one discovery that's still waiting to happen.

Image courtesy Flickr user Mykl Roventine, via CC


  1. If there was an evolutionary niche to be filled, there was probably at least one dinosaur species to fill it. Then again, maybe this was one of the factors that enable the early mammals survive whatever killed off the big lizards.

  2. Wow, thanks so much Maggie for answering my little guy’s question, he is going to be so overjoyed when I show him this. I am off to find night-time reading on coprolites for him!

  3. Gods, thank you! I LOVE it when someone answers a kid’s science question with, “we don’t know, yet, but if you study, you could be the one to figure it out and tell us.” If more kids were told that in school, more of us would understand that “learning science” isn’t just memorizing wisdom handed down from on high by people who already know all the answers.

  4. IIRC, perhaps from “At The Water’s Edge” or “Your Inner FIsh” (or maybe Bill Bryson’s book on the history of everything), the first land dwellers (from fishy things) were carnivores, and herbivores came later (so we think currently given what we know). The writing I recall mentions how meat eaters might have slowly transitioned (over thousands of years) by eating meaty little critters that were on leaves or plants, and ingesting some of the plant material with the little snacky creature. If I have recalled that correctly, there were clearly omnivorous creatures, although I don’t know if they were dinosaurs or before dinosaurs.

  5. There were carnivores. There were also herbivores. It is reasonable to assume that whatever transitional species sat between the two ate both at some point.

  6. That picture reminds me of something along I-90 in South Dakota. Where is the photo from?

    I really like this idea for a series. I have a feeling I will learn a lot, even though I am not a toddler. =]

  7. Agree about the learning. Toddlers unbridled curiosity throws these interesting curveballs regularly.

    Brilliant idea for a regular feature, and this answer was interesting, if somewhat unfulfilling ;)

  8. Definitely agree with Ben. There are clear instances where herbivorous dinosaurs descended from carnivorous lines, which strongly implies intermediate forms.

    More importantly, though, it’s clear that animals are rarely so picky about their choices. Alligators, for example, will eat fruit. Hell, even a supremely-vegetarian-adapted cow will in rare cases scavenge dead things (I’m thinking of a picture captioned “hare lip”) when they’re short on certain nutrients. It’s true of a lot of otherwise apparently vegetarian or carnivorous animals.

  9. We went to a local nature/science center yesterday and hung out for a bit at the “Dino Pit.”

    There was a group of college students completing an assignment there, which consisted of digging out the sand covering various model dinosaur bones. The students dug and sketched while a handful of toddlers scurried underfoot. (Sorry guys!)

    My 3 year old was really intimidated by the college students because he became very downcast and finally said to me, “I want to be a paleontologist, but it’s so so hard!” Well, imagine if you were three and walked into a college level class. You’d think it was hard too!

    I keep hoping he’ll ask a really good question I can submit to Maggie, but the best he’s come up with so far is, “How are we supposed to get off of this strange planet!?!” Then I told him we have to wait for the mothership….. just kidding! :)

  10. There’s a new-ish theory going around that Ceratopsians may have also been omnivorous, sort of like giant Cretaceous boars

  11. What a strange bit of serendipity. My daughter was asking me about this just last night.

    Now I have an answer for her. Awesome.

  12. I arrived home this evening and asked my 8 year old son who was a paleontologist for halloween if there were any omnivorous dinosaurs and he said “Avimimus” and showed me in one of his dinoencyclopedias that it was. Wikipedia says it may have been

  13. Many herbivores have been documented snacking on animals presumably to correct nutritional deficiencies. For example sheep and deer will eat baby birds, presumably for their calcium content.

  14. I totally had a raptor escape plan too. Still do… Jurassic Park was my favorite weekend movie from the ages of 9-12, it made a lasting impression.

  15. “I arrived home this evening and asked my 8 year old son who was a paleontologist for halloween…”

    That itself is awesomeness.

  16. I am a professional paleontologist. I work at the Museum of Northern Arizona in Flagstaff, Arizona. My team discovered the recently described therizinosaur that we named Nothronychus graffami. It was excavated from a site in southern Utah, and it is the most completely known skeleton of the entire family of therizinosaurs. We had a 2 year exhibit on the discovery, and its many puzzles. It was called “Therizinosaur, Mystery of the Sickle-Claw Dinosaur.” That exhibit was moved to the Arizona Museum of Natural History in Mesa, Arizona in September and will be there for one year. The Museum of Northern Arizona published a popular account of these mysteries in our Plateau Magazine. It sells for $10. It has lots of wonderful art, and it presents the entire story as a set of hypotheses. One concern is feeding behavior, which we posed as a mystery: specialized carnivore (say ants or termites), herbivore, or a combination in which case it was an omnivore. I would be glad to forward any requests for the Plateau issue to our sales office at MNA. I am the author.

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