Research News: Dinosaur dads cared for young, researchers say

The News:
Dinosaur Dads Cared For Young, Researchers Say
by Christopher Joyce
Morning Edition, December 19, 2008 · It could very well be that some of the fiercest, meat-eating dinosaurs were also attentive, caring dads.
That's the conclusion from scientists who have been studying dinosaur eggs and the bones of dinosaurs found next to, or in some cases on top of, dinosaur egg clutches.
Paleontologist David Varricchio of Montana State University says he thinks many of those nest-sitters were males. His evidence is based partly on what scientists know about modern birds, the descendents of dinosaurs.
Varricchio measured the mass of egg material in dinosaur clutches and compared it to the mass of the dinosaurs that were found with the eggs. It showed that among some species of dinosaurs — Oviraptor, Troodon and Citipati — the mass of the clutches was very big compared to the size of the parent.
Varricchio then looked for other egg-laying animals where egg mass is high compared to parent body size — and came up with ostriches, emus, kiwis and several other kinds of birds. And among all of these modern birds, the male is the primary caretaker; he broods the eggs and cares for the young.
This may be rather indirect evidence. But writing in this week's issue of the journal Science, Varricchio also notes that the dinosaur bones found at these egg sites lacked something called "medullary bone." Read on...

The Research:
Read the research behind this story in the journal Science. Also, read this commentary in Science "Who's your Daddy? "