Explanation?
I have heard arguments for why adult dinosaurs would have been featherless along the lines of, the babies had them and lost them as they aged. However, I have always wondered about this. Modern birds are born without considerable, if any, feathers and gain more as they age, so wouldn’t that be theoretically the same or similar with non-avian theropods? If so, that would suggest if the species had feathers they gained more as they aged, or didn’t have them at all. Maybe you can give me some more insight into this, thanks.
One important thing to remember is that not all birds are born featherless. Many, including chickens, ducks, and ratites (the earliest groups to branch off) are precocial - they’re born feathered and capable of walking around. Altricality is the derived condition, not the ancestral one. Most mesozoic dinosaurs were probably precocial.
As for the whole “losing feathers as they aged” - there’s not really any direct evidence for it that I’m aware of; it’s just speculation. I would agree that certainly many dinosaurs would have gained more feathers as they grew.
The idea of losing feathers as they age comes from the fact that smaller organisms have more difficulty regulating their temperature than do large ones (think about how long it takes for a puddle to cool down as compared to a lake).
deepintheshadyglen