Wilderness Underfoot: Dinosaur caretakers

StoryImage( ‘/Images/Story//Auto-img-112792623723730.jpg’, ”, ‘Nurtured or abandoned? – Whether the dinosaur in this egg would have been cared for or left to fend for itself is hard to answer. Paleontologists must rely on circumstantial evidence to build a picture of a dinosaur’s habits and lifestyles. Chances are, dinosaurs varied quite a lot in caretaking of their young.’);
StoryImage( ‘/Images/Story//Auto-img-112792626521295.jpg’, ”, ‘Evidence of caretaking – A nest with an adult Psittacosaurus and 34 babies gathered around. This fossil was found in early Cretaceous rocks in China. The dinosaurs were mostly upright, suggesting they died suddenly—perhaps during a volcanic eruption. The skeletons are all articulated, meaning they hadn’t been torn apart as they would have been had they been caught and gnawed on by predatory dinosaurs. The young are all the same size and age. Psittacosaurus was a plant eater, so there is no reason to believe the adult was preying on the young. With evidence like this, it’s hard to conclude anything other than this is a parent that had been caring for its offspring. ‘);

We now have clear evidence of parenting in some dinosaurs

One of paleontology’s hottest debates is whether adult dinosaurs took care of their young. When it comes to figuring out how these creatures behaved in their daily lives, the clues aren’t easy to come by. The most common dinosaur remains—bones—tell more about how the creatures looked than how they behaved. From bones we can determine dinosaur sizes and shapes, muscle mass, and certain diseases and injuries the animals might have suffered. Teeth reveal their diets.

As to the question of how they parented their young, Jack Horner was among the first paleontologists to make a case for nurturing. He had studied fossils of Maiasaur eggs, embryos, and offspring, and concluded the young were too undeveloped after hatching to care for themselves. He reasoned that partially digested berries found in nesting sites suggested parents regurgitated food for their young—much like birds do.

Fossils, such as partially digested berries, are considered “trace fossils” in that they are traces of an organism’s activities. Other trace fossils have been discovered that offer evidence of dinosaur herding in large family groups. These are trails of various sizes of footprints left by long-necked sauropods at sites in North and South America, and by bipedal dinosaurs at the Isle of Skye in Scotland.

But perhaps the most compelling evidence of dinosaur parenting is the remains of a Psittacosaurus and what appears to be its 34 offspring. This fossil offers convincing proof that at least some of the dinosaurs cared for their young.

From the Sept. 28-Oct. 4, 2005, issue

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