CHICAGO -- A rare dolphin at Chicago's Shedd Aquarium is expecting a calf in May.

Tique (TEE'-kay) is one of the few Pacific white-sided dolphins currently living in a zoo or aquarium.

Ken Ramirez, executive vice president of Animal Collections and Training at the Shedd, says there are fewer than 20 of the dolphins in North American facilities.

ique is 26 years old and weighs about 200 pounds.

She and another female dolphin were taken to live with male dolphins at the Miami Seaquarium as part of a breeding partnership where they lived there with male dolphins for two years and returned to the Shedd in the fall.

Dolphin pregnancies last approximately 12 months. The calf is expected in mid-May.