Leo and his mom and dad are arboreal. They spend most of their lives in trees and are so dexterous almost no predators can catch them.
13-year-old zoo visitor Nicole Kim agreed that they seem almost human the way they care for their young. "They eat just like we do," she said. "It's really cool."
"I've never seen a monkey that small before," said 12-year-old Vanessa Ortiz.
"I thought it was really cool how they put their baby on their stomach and they just hold on," said 13-year-old Caroline May.
The zoo also welcomed, less than five months ago, a new baby shifaka. That's a type of lemur from Northwestern Madagascar. The shifaka is named Polamalu and was born Feb. 1st of this year.
The adult prairie dogs were on "look out" at their habitat today. Our camera spotted a fuzzy little one emerging from his hole.
19-month-old Aliyah Shue quickly blew her a kiss. And then she was ready to move on.
Abigail, the zoo's newest baby giraffe, relaxed in the shade as her parents Stella and Gus stood nearby. Abigail will be one year old in July.
And even though Batu the orangatan is already a toddler - he'll be two in October - he still stays close to Mom.
"You know what 'orangutan' means?" asked 9-year-old Steven Green. "It means the man of the forest."
As 9-year-old James Salmon observed, "The baby likes the mom to carry it around very much."
And on hot muggy days, Dad puts a big tub on his head for shade!
There are many more new babies that will soon be on display at the Philadelphia Zoo. They include chicks and ducklings, snakes and birds.
Click here to see a slideshow of some of the zoo's recent arrivals.
