A bottlenose dolphin at a Chicago zoo gave birth to a calf early Saturday morning with the help of a fellow mom, in a successful birth recorded on video by zoo staff. The dolphin calf was born at Brookfield Zoo Chicago early Saturday morning as a team of veterinarians monitored and cheered on the mom, a 38-year-old bottlenose dolphin named Allie. “Push, push, push,” one observer can be heard shouting in video released by the zoo Saturday, as Allie swims around the tank, the calf’s little tail fins poking out below her own. Then the calf wriggles free and instinctively darts to the surface of the pool for its first breath. Also in the tank was an experienced mother dolphin named Tapeko, 43, who stayed close to Allie through her more than one hour labor. In the video, she can be seen following the calf as it head to the surface, and staying with it as it takes that first breath. It's natural for dolphins to look out for each other during a birth, zoo staff say. “That’s very common both in free-ranging settings but also in aquaria,” said Brookfield Zoo Chicago Senior Veterinarian Dr. Jennifer Langan. “It provides the mom extra protection and a little bit of extra help to help get the calf to the surface to help it breath in those couple minutes where she’s still having really strong contractions.” In a written statement, zoo officials said early signs indicate that the calf is in good health. They estimate it weighs around 35 pounds (16 kilograms) and stretches nearly four feet in length (115-120 centimeters). That is about the weight and length of an adult golden retriever dog. The zoo’s Seven Seas exhibit will be closed as the calf bonds with its mother and acclimates with other dolphins in its group. As part of that bonding, the calf has already learned to slipstream, or draft alongside its mother so that it doesn’t have to work as hard to move. Veterinarians will monitor progress in nursing, swimming and other milestones particularly closely over the next 30 days. The calf will eventually take a paternity test to see which of the male dolphins at the zoo is its father. Zoo officials say they will name the calf later this summer.