Re: Good Mother Dinosaurs

[dis@gj.net]

Masilla62@aol.com wrote:

  My prof says the debate is revolving around wear
> patterns on the baby dino's teeth.  He said Horner pointed to this as proof
> the babies were being feed by parents (good mother dinosaurs) because they
> were still in the nest and had wear patterns.  Later, other scientists said
> the wear patterns were caused by baby dinosaurs grinding their teeth while
> still inside the eggs. 

We have probable hatchling Dryosaurus with worn teeth. Grindingtheir 
teeth in the egg was perhaps to get the teeth premodified for eating 
plants on hatching.

 My question is why can't they use experimental
> archaeology on the teeth to determine the cause of the wear patterns?

Good idea!

My own research along these lines has been tied to nesting sites of the 
Jurassic ornithopod Dryosaurus. I think these dinosaurs left the nest 
when they hatched, but...  In addition to finding babies and eggs in 
these sites, we also find yearlings "` 1/3 grown" (two size classes in 
several sites). My thoughts are that the young follow the mother like 
ducklings. She eats something, they eat it. She avoids something, they 
avoid it. Learning by mimicry.
        The yearling bones in the sites are perhaps from the young ones 
that followed mom all the ways back to the nesting site and starved 
waiting for her to lead them to food.
        The group of juvenile ankylosaurs (siblings?) found in Mongolia 
by the Sino/Canadian expeditions lends some support to the young 
sticking together for some time after hatching. Mom would provide a 
focus. 
        It would not be that far to ga to get the mother feeding the 
young. But...... proof, who knows.

Jim K.