When Roothie the red kangaroo arrived at Potter Park Zoo in May of 2017, zookeepers knew there was a chance she could be pregnant.

Turns out she was.  Zoo officials noticed her pouch was getting bigger in November, and that's usually about 100 days in.

Officials saw the pouch move so they backtracked and realized that the joey was born sometime in August.

The joey, that's what you call a baby kangaroo, was the size of a jelly bean when it was born.  When the joey starts coming out of the pouch, it's about 150 days old.

Zookeepers are working on getting it used to their presence, they still don't know if it's a boy or girl or exactly how big it is.  Here's more from the Lansing State Journal.