A 56-year-old rhinoceros, the oldest in the U.S., has died in Tennessee after exceeding the median life expectancy for her species by nearly 20 years. Zoo Knoxville announced Feb. 6 that Dolly the Southern white rhino had experienced severe mobility issues in recent days, leading to the decision to euthanize her.

Zoo Knoxville said goodbye to a beloved southern white rhino named Dolly, who was the oldest rhinoceros in the United States at 56 years old. The zoo says Dolly was euthanized after her mobility declined significantly.