How long do dinosaurs live? Do carnivores live longer than herbivores? If being a herbivore (vegetarian) makes you live longer, then why didn’t the carnivores switch or become omnivores? Do omnivores live longer than either of the others?
This all started with a simple off-hand question from one of my students last spring – How long do dinosaurs live? We talked about it for a few minutes. The only conclusion we reached was that carnivores must live longer because they are eating the herbivores. After all, if you have been eaten, then obviously you’re not living as long. This satisfied the kids but it left me with more questions. Of course I need answers and my first stop was the dinner table that night. In sharing about my day, I mentioned the conversation about the dinosaurs. We discussed it but none of us had any better answers. The one new bit of information came from Bella. In “Land Before Time”, Little Foot (a herbivore) has grandparents. Chomper (a carnivore) doesn’t. Which brings us to the opposite conclusion from what we decided at school. In this example, the herbivores are living longer.
This is all well and good but it’s not really answering my question. I put out a call for any local dinosaurs that might be available for an interview but for some reason didn’t get any responses. Which leaves me with Google.
Dear Google, how long did dinosaurs live?
One way that scientists use to determine how old a dinosaur was when it died is by examining the growth rings in the bones. Similar to growth rings in trees, the number of rings tell us how many years the dinosaur lived. The spacing of the rings can also tell us how quickly or how slowly the dinosaur grew during its life.
Another theory considered by scientists is the metabolism theory. Warm-blooded animals live shorter lives and cold-blooded animals live longer lives. While it is hard to tell from a fossil whether an animal was warm or cold-blooded, it is generally accepted that dinosaurs were lizards and therefore cold-blooded.
If you go by size vs lifespan charts, smaller animals live longer than larger animals. Based on this theory, the size of the dinosaur is more of a key factor in lifespan than diet, which is what my students were basing their guesses on. Here’s a link to a chart that shows the average lifespan of various animals (click here).
So, in conclusion… I have no idea how long dinosaurs lived! And neither does anyone else really. Except the dinosaurs and they’re not talking!
I’ll leave you with this quote from Bob Strauss writing at ThoughtCo.
Until we establish more details about the metabolism and growth rates of various species, any serious estimates of dinosaur lifespans have to be taken with a gigantic grain of prehistoric salt!
Inquiring Minds Want to Know
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