Elderly Sloth Bear Dies at the Smithsonian’s National Zoo

Merlin, the National Zoo’s senior male sloth bear, died this morning after a 48-hour illness. On Monday morning, Nov. 2, he underwent a routine physical examination. Although the examination went well, his anesthetic recovery was prolonged, and he had not returned to normal by the afternoon.  While under observation, veterinarians noticed that he had vomited some blood-tinged fluid. 

Due to concerns with this prolonged recovery, the vomiting and his previous medical history of a gastric volvulus (“twisted stomach”) in 1994, he underwent additional evaluation and diagnostics at the National Zoo’s hospital later the same day. Based on the results of his blood work, ultrasound and radiographs, the animal care team determined he required surgery, during which they corrected a partially twisted spleen. Following the procedure, Merlin showed signs of increased wakefulness, but never fully recovered. Sequential blood work analysis suggested additional metabolic compromise, including possible circulatory shock and renal failure.    

The bear was attended by staff who remained on 24-hour watch and provided intensive care continuously for two days, until he passed away this morning. A necropsy will be performed later today, but results will not be available for several weeks. 

Merlin was born at the National Zoo in December 1981. He sired a total of seven cubs.  The Zoo has two females on exhibit, Hana and Khali.

National Zoo scientists have been doing research on sloth bear conservation since the 1970s and have estimated that about 6,000 to 11,000 sloth bears remain in the wild with their biggest threat being the loss of habitat. The IUCN’s Red List of Threatened Species categorizes sloth bears as vulnerable.

In the wild, these animals are found in the forests of India, Sri Lanka and Nepal. A 2008 Association of Zoos and Aquariums’ Species Survival Plan Life Table reveals that the oldest male sloth bear in captivity died at age 29. 

Sloth bears have shaggy, dusty-black coats, pale, short-haired muzzles and long, curved claws that they use to excavate ants and termites. Additionally, their long snout, along with their lips, allows them to create a vacuum-like seal to suck up the insects. Sloth bears are the only bears to carry young on their backs.

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SI-495-2009