The first member of an endangered monkey species to be born at the Toledo Zoo died Wednesday of congestive heart failure.
Tien, a male Francois langur, began receiving treatment last month because it showed signs of respiratory problems.
Though Tien responded partially to treatment, it became increasingly lethargic and anorexic, zoo officials said.
When the langur was examined Tuesday, its heart was enlarged and fluid was building up in its abdomen. Treatment was started to slow the heart disease and comfort the animal.
An examination in January revealed no signs of heart disease in Tien, Dr. Chris Hanley, zoo associate veterinarian, said in a statement. Although the necropsy indicated cardiomyopathy as the cause of death, further tests may help determine the exact cause of the heart failure.
Tien was born in July, 2002, the first Francois langur birthed at the zoo, the offspring of female Ashes, now about 12, and male Dong Puong, now about 13. The parents survive at the zoo, as do its brothers, Treiu Bay, born in July, 2004, and Chay, born in September, 2008.
The species, native to southwestern China and northeastern Vietnam, is listed as endangered by the World Conservation Union, with its numbers in the wild decreasing through habitat loss.