The St. Louis Zoo family has grown by one as the Primate House welcomes a new addition.

Willow, a black and white Colobus monkey, was born on January 10. Her name means "graceful," like the tree of her namesake.

PHOTOS: Colobus monkey Willow

Willow is the newest baby of 17-year-old Cecilia. Her two big brothers, 1-year-old Ziggy and 2-year-old Simon, are getting to know their baby sister and learning to carry her around.

When Colobus monkey's are born, their hair is all white and they have a pink face. As they grow, their fur turns black with white hair encircling their faces and half their tails. They reach adult coloration around 6 months.

Willow and her brother Ziggy, who was named for the late David Bowie, share a birthday!

Photos: Meet Ziggy

You can visit the entire family at the Primate House.