Instructions
Look at its size. It is obvious to tell a newborn from an adult, but you'll have to look a little closer at a juvenile's length to tell its age. Baby cottontails leave their mother's nest when they are five inches long, or about four to five weeks old. A full-grown adult is 14 to 18 inches long.
Look at the amount of hair on the rabbit. Cottontails should start looking fluffy at two and a half weeks old. At three to four and a half weeks old, its fur should stand out from its body. At four to five weeks old, the bunny should look like a small version of an adult.
Check out its reaction to you. If it is jumpy and its ears stood erect when you approached, it is probably at least three and a half weeks old.
Look at its eyes. This can be helpful to tell the age of a very young rabbits. If its eyes are open, the rabbit is at least ten days old. A bunny's eyes start to open when it is between seven to nine days old.
Look at its surroundings. If it is still in its mother's nest, the baby is three weeks old or younger. If it is hanging around the nest, it is probably between three and four weeks old, nearly ready to leave the nest. Also, if it is still drinking its mother's milk in the nest, it is three weeks or younger.
How to Tell the Age of a Cottontail Rabbit
Cottontail rabbits look like many other gray rabbits, until you look at the tail. It's distinguished by the stubby ball of fur on its backside that looks like a cotton ball. They are common in the wild and not recommended as good pets. If you've found a little one on a walk, you might wonder how old it is. There are several ways to tell, including if it is living out on its own. The cottontail bunny is made to survive by itself at a surprisingly young age.