Scientists have come across a fossil of a baby dinosaur so small that humans would have to stoop to touch it.
However if it had survived to reach full size, the dinosaur would have been as big as a fire truck. It’s remarkable to think that it would have grown so large given the fact that it emerged from the egg as a tiny creature that would have reached as high as a human ankle.
Rapid growth rate evidenced by fossil
It is thought that the dinosaur was around two months old when it died, having reached around knee height.
“It grew from this … Chihuahua-sized dinosaur at hatching to a golden retriever-sized dinosaur when it died in just a few weeks,” said Macalester College’s Kristi Curry Rogers, co-author of a study describing the specimen.
This is the first time that scientists have found such a well-preserved fossil of a small baby sauropod, a group of long-necked plant-eaters that includes the Brontosaurus. Previous discoveries of young sauropods have been embryos, older than the new fossil, or so badly destroyed that they are impossible to identify.
Baby dinosaur a goldmine of information for scientists
Although the dinosaur died before it could reach its prime, it has now provided a major boon for scientists. The young dinosaur left behind lots of valuable information on dinosaur development and parenting, which was sorely lacking in this case.
Previously there was a gap in our knowledge of sauropods from “elephant-sized (to) when they were embryos in the egg,” says paleobiologist Holly Woodward of the Oklahoma State University Center for Health Sciences, who was not involved in the study. Woodward says the new find “is the key fossil right now for understanding that period of a sauropod’s growth.”
The strange thing about the find is that Curry Rogers wasn’t even looking for baby dinosaurs in the area. She was in fact hoping to find crocodiles and turtles among the drawers of fossils dug up in Madagascar. However she kept finding little versions of the bones of a dinosaur that she discovered more than 10 years prior.
That dinosaur is the Rapetosaurus, a sauropod that roamed the Earth towards the end of the Cretaceous period.
It is possible that the baby Rapetosaurus died of starvation when it was aged between one to two-and-a-half months old. The researchers say that the small reptile was probably able to run, jump and go onto its hind legs, movements which the larger adults could no longer perform.
Other sauropods could have grown up differently
According to evidence from the baby’s bones, it grew like a weed. The finding provides evidence for the assertion that sauropods grew rapidly from the beginning of their lives, potentially to protect them from predators.
Among the features observed in the bones are some that are common to other types of animals that are expected to take care of themselves from a young age. Evidence of parenting by dinosaurs has been discovered, but Rapetosaurus apparently left their young to wander free.
Curry Rogers says that this is not unexpected. There are evolutionary advantages in ignoring offspring, and the huge size difference between parents and children would have made things difficult. It’s difficult to see how “such large parents (could) take care of such tiny babies … without stepping on your offspring,” she said.
Paleobiologist Martin Kundrat of Slovakia’s Comenius University, who was not part of the study, warns that the findings do not necessarily apply to all sauropods. However he supports the conclusions of the study.
“This is not the end of the story,” Curry Rogers agreed. All the same, “it’s nice to finally have a little look at what might’ve been going on with those dinosaurs.”