Dinosaurs Needed Babysitters, Too

A 120 million-year-old fossil has revealed a new, rather endearing discovery about dinosaurs: They may have had babysitters to watch over their youngsters.

The fossil was originally discovered in northeastern China and appeared somewhat unremarkable to the amateur paleontologists who found it. But now, University of Pennsylvania researchers Brandon P. Hedrick and Peter Dodson are taking a closer look. "I saw a photo of it and instantly knew I wanted to explore it in more depth," Hedrick said.

The 2-foot-wide fossil contains the remains of 24 baby dinosaurs from the Psittacosaurus lujiatunensis species. As adults, these were gazelle-sized vegetable-eaters with strong beaks on their upper jaws (if you need a better visual, the species name is Greek for “parrot lizard”). P. lujiatunensis is one of the most common dinosaur species in science—hundreds of its fossils have been discovered across China, Mongolia, and Russia. But what makes this one unique is the 25th dinosaur in the nest, which is older and much bigger than the others—but not old enough to have been the parent. Instead, researchers think it was an adolescent—a teenager, if you will—tasked with keeping guard over the kids while the parents were out on a dino date.

This kind of babysitting is seen in modern birds. In fact, one study showed that 9 percent of bird species utilize babysitters to protect the family by warding off dangerous predators. These birds don’t reproduce, but do their part to pass on the family genes by ensuring the youngsters grow up healthy. The babysitting dinosaur could also have been an older sibling looking after its brothers and sisters.

Unfortunately, caretakers can only protect little ones from so much. Researchers think these 25 dinosaurs were killed by rock and water flow associated with a volcanic eruption. Dodson and Hedrick will examine the bones further to learn more about the creatures.