Gizmo gave birth to the male on September 26, the zoo said. Another baby squirrel monkey was born just a couple weeks later on October 15, and a third is still on the way.
The two newest arrivals have not yet been named.
Last year, four squirrel monkeys were born at the zoo. They were named Chalupa, Arlo, Taco and Basil.
They can all be seen daily in the zoo's "Tropic World: South America" habitat, which is always in the 70s.