The Dinosaur's Happy Happy Day

Answer 1

We might suppose that dinosaurs were happy when they had plenty of food, weren't being chased or stalked by predators, had successfully mated, saw their eggs hatch, weren't too hot or too cold and weren't suffering from any wounds or aches.

However, we don't really know if dinosaurs had the part of the brain that causes what we call "happiness," the limbic system. They may have been limited to what is known as the "R complex" (R is for "reptile." although fish also have this part) which just tells them to do simple things such as "run away," "bite that" or "get under the shade."

Then again, some dinosaurs had brains as big (for their size) as birds and birds certainly SEEM as though they can be happy, so who knows?