An endangered crowned lemur was born at the zoo on April 15. The baby lemur has two older siblings, Lenny and Volana, who also live at the zoo.
Zoo officials still do not know the measurements or sex of the crowned lemur because its mother, Tucker, is keeping the newborn close.
The zoo said crowned lemurs are considered endangered because of forest loss caused by slash-and-burn practices, charcoal production and other human-wildlife conflict.
The newborn and the rest of the lemurs are on exhibit at the zoo, which is open daily from 10 a.m. to 5 p.m.
This is the fourth crowned lemur birth at their facility, Lincoln Park Zoo said.