CHICAGO (CBS) — A mother dolphin suddenly and unexpectedly lost her unborn calf this week at the Shedd Aquarium.

The Pacific white-sided dolphin named Piquet, 31, was expected to deliver the calf in October.

“While we are saddened by this loss, we are grateful that mom is doing okay and, as always, we are ensuring she has everything she needs at this time,” Peggy Sloan, Shedd Aquarium’s chief animal operations officer, said in a news release.

Everything had been progressing normally for Piquet’s pregnancy over the past 10 months, including routine observations, data monitoring, and weekly ultrasounds, the aquarium said.

But on Monday evening, caregivers found that the dolphin’s fetal membrane had prematurely ruptured and immediately began providing her round-the-clock care. The Shedd’s expert team also consulted with scientific advisers from the National Oceanic and Atmospheric Administration, the American Veterinary Medical Association, and human health organizations.

Tragically, the veterinary staff at the Shedd confirmed that the calf had died on Wednesday evening. The cause remains unknown.

Piquet The Dolphin

Piquet the Dolphin at the Shedd Aquarium. (Credit: Shedd Aquarium)

Mother dolphin Piquet, whose name translates to “female of small stature” in the language of the Tlingit people, has been eating and interacting with the animal care team.

She is swimming with another dolphin, Kri, at the Abbott Oceanarium, but is off display for now, the Shedd said.