Associated Press photos
This photo provided by the Chicago Zoological Society shows bottlenose dolphins from left, Spree, 10, Tapeko, 31, and Allie, 26, at the Brookfield Zoo in Brookfield, Ill. Officials at the zoo say all three dolphins are pregnant and are due to give birth this summer and fall. Allie has had two previous calves and Tapeko, three. But first-time mother Spree will require extra care as her pregnancy will have greater risks, as with other mammals. Chicago Zoological Society | Jim Schulz
Jennifer Langan, center, associate veterinarian for the Chicago Zoological Society, performs an ultrasound on Allie. Langan is assisted by keeper Kristina Fliss, left, and Kate Sladek, a senior veterinary technician. The care staff provides to the pregnant dolphins is facilitated by the trusting relationships the animals have with their trainers and the veterinary staff.