LAS VEGAS (KLAS) — Another dolphin at the Mirage’s Secret Garden and Dolphin Habitat has died, the resort confirmed Wednesday.

Duchess, one of the five original dolphins at the habitat, is the fourth dolphin to die in less than a year. She was 48.

“With a heavy heart, I share that Duchess, our matriarch bottlenose dolphin and beloved member of The Mirage Secret Garden and Dolphin Habitat family, has passed away. Duchess was 48 years old, one of 5 original dolphins that opened the Habitat in 1990,” a statement from Mirage President Joe Lupo said.

Last April, 13-year-old Bella, who was Duchess’ granddaughter, died after undergoing treatment for gastroenteritis for several weeks. In early September, 19-year-old Maverick died following treatment for a lung infection. Weeks later, 11-year-old K2 died while in the process of receiving treatment for a respiratory illness.

The facility temporarily closed after K2’s death before its permanent closure was announced last November.

“I extend my heartfelt appreciation to the Mirage animal care team and the veterinary experts who worked tirelessly to ensure Duchess was loved, received the highest quality care, and was as comfortable as possible. Duchess brought an unmeasurable amount of joy and happiness to the countless visitors and The Mirage family while at the Dolphin Habitat,” the statement continued.

MGM had previously announced it was going to sell The Mirage to Hard Rock International. Hard Rock’s leadership team announced it would eventually permanently close the habitat before beginning construction of the Guitar Hotel and other planned redevelopments, according to a letter sent to Mirage employees.

Wild bottlenose dolphins typically have lifespans of 40 to 60 years, according to the National Marine Fisheries Service.

8 News Now reached out to the Mirage Las Vegas about how many dolphins remain on the property and when it plans to permanently close the exhibit.

The Secret Garden has been closed to the general public while Duchess was receiving treatment.  We do not intend to re-open the facility to the general public in the manner it was previously operated while we endeavor to relocate the remaining Dolphins, Tigers, Lions and Leopards.  We are planning some upcoming periodic visitations and educational programs to our valued team members and their family members and other invited guests.

Joe Lupo, President, The Mirage Las Vegas