Zoo moms and babies (44 images)

A baby Coquerel's sifaka, an endangered lemur species from Madagascar, sticks its head out as his mother holds him at the St. Louis Zoo on March 19, 2009. (UPI Photo/Bill Greenblatt)

Three trumpeter swan cygnets that hatched last week follow closely behind their mother at Lincoln Park Zoo on June 18, 2009. (UPI Photo/Greg Neise/Lincoln Park Zoo) .

Five critically endangered Amur tigers were born at the Saint Louis Zoo in St. Louis on April 28, 2008. (UPI Photo/St. Louis Zoo)

A black rhinoceros calf was born to first-time parents, mother Kati Rain and father Ajabu in St. Louis on January 14, 2011. UPI/Saint Louis Zoo