Cortisol and other hormones release a surge of energy in the form of glucose (sugar), which the body can use to fight or flee. That rush of glucose is no problem if your body's insulin response is working correctly.
Notice that the kittensâ ears are just beginning to unfold, though their eyes remain closed. Their sense of smell, hearing, and taste are slowly starting to develop. Tweed is only three days old. After almost a week, the kittens begin to wiggle around on their own a little bit and their eyes start to open.
Kittensâ eyes generally change color between two and three months of age. However, in this matter like all aspects of maturing there are individual variations. Some kittens mature earlier than others. And some kittens keep their blue eyes into adulthood (think Siamese).