The Smithsonian’s National Zoo has lost Rolles, one of its endangered Przewalski’s horses, after the 23-year-old was euthanised in the early hours of Friday morning.
Rolles had been suffering from a tumor in his nasal area. A final pathology report will provide more information.
In July, keepers observed that Rolles had some nasal discharge. Zoo veterinarians prescribed oral antibiotics, which helped initially. About 10 days later, he developed a visible mass on the side of his nose. Rolles also lost weight and rubbed the affected area, an indication that the mass caused him discomfort.
Zoo veterinarians, in consultation with an outside equine veterinarian, performed a full examination on Rolles, including X-rays and nasal endoscopy. The location of the tumor greatly limited the options for treatment. Animal care staff elected to humanely euthanize Rolles based on his poor long-term prognosis.
Born at the Bronx Zoo June 10, 1990, Rolles arrived at the National Zoo in 2008. Rolles served as a non-breeding companion for Rose Marie, the Zoo’s 27-year-old female Przewalski’s horse. He also acted as an educational ambassador for his species, illustrating the social nature and behavior of Przewalski’s horses to scientists, keepers and Zoo visitors.
Visitors can see Rose Marie on exhibit adjacent to the Small Mammal House.
This species is considered endangered by the International Union for Conservation of Nature’s Red List of Threatened Species.
Scientists at the Zoo’s Smithsonian Conservation Biology Institute recently celebrated a huge breakthrough for the survival of this species with the birth of a female Przewalski’s horse — the first born via artificial insemination.
Przewalski’s horses have 66 chromosomes, two more than domestic horses. Their Mongolian name is “takhi,” which means “spirit”.
The Chinese call the Przewalski’s horse “yehmah.”
These horses were scientifically described in the late 19th century after Polish naturalist Colonel Nikolai Przewalski obtained a skull and hide of this seldom-seen animal and shared them with scientists at a museum in St. Petersburg.