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Where Are All the Baby Dinosaurs?

Infant dinosaurs are little bundles of joy. They can kindle the same "oohs" and "awws" induced by mammalian neonates and -- as a bonus -- young dinosaurs often lack the ability to tear you limb from limb, unlike their adult counterparts.

Over the years we've seen plenty of dino babies in films and on television. For example, Jurassic Park featured a Velociraptor birth early in the movie, which prompted John Hammond to coo like a nurturing mother as the tiny, man-eating carnivore struggled to break free from its shell. (Though, in real life, Velociraptor was about the size of a turkey and likely couldn't eat a man.) Most memorably, the adorably plump and playful Baby Sinclair from the television series Dinosaurs caused many a viewer to uproariously laugh as we watched him spout, "Not the mama!" at his poor father, often while hitting him with a pot.

BabySinclair.JPGBut while baby dinosaurs are noticeable in the modern media and have recently been the focus of major paleontological discoveries, for many years, they were not quite so copious in the fossil record. Before 2000, nobody had ever seen a juvenile triceratops. Why is this? Speaking at TEDxVancouver last November, esteemed paleontologist, Jack Horner partially blamed hubris:

...scientists have egos, and scientists like to name dinosaurs. They like to name anything. Everybody likes to have their own animal that they named. And so every time they found something that looked a little different, they named it something different.
Besides the ego issue, Horner also added that museum curators succumbed to a preoccupation with size in the early 20th century:

Every museum wanted a little bigger or better [fossil] than anybody else had. So if the museum in Toronto went out and collected a Tyrannosaur, a big one, then the museum in Ottawa wanted a bigger one and a better one. And that happened for all museums.
So, because curators selected for size, smaller fossils were disregarded. And because scientists had egos, many younger dinosaurs have actually been misconstrued as being different species.

In order to halt these trends, Horner has been collecting plenty of juvenile dinosaurs for the Museum of the Rockies, and he has also been making dinosaur species go extinct (for a second time), an action that has not made him popular with children, he says.

By looking at the bone histology of fossils, he and his students have been able to pinpoint identical species and eliminate duplicates. Analysis of dentition and cross-sections of bone have supplied useful proxies for their research. Of the team's many discoveries, they have found that Torosaurus is, in fact, a grown up Triceratops. (Edit: New research published Feb. 29 has disputed this finding.) And Nanotyrannus is actually an infant Tyrannosaurus. (Imagine that.)