Study suggests: Tyrannosaurs had life easy until they hit their teens
This popped in from CBC News's science team, which is pretty good:
Young dinosaurs lived in packs with nurturing parents like modern mammals, paleontologists who studied a group of fossils in Alberta's Badlands say.
[ ... ]
The study said the average mortality rate from ages two to 13 was about 3.7 per cent, jumping to 22.9 per cent between ages 14 and 23.
The survivorship pattern paints a picture of parents who shield their offspring until their young are old enough to breed. The behaviour is seen in large modern mammals, such as male elephants that usually stay with their birth herd until puberty.
(Note: I've come to suspect, through reading about the life and times of alligators , that the "reptilian brain" hypothesis - that reptiles can't have feelings - may be way too easy to be true. Hey, if 'gators care, why not dinos?)