For three decades, Old Man selflessly helped scientists unravel the mysteries behind Alzheimer's, osteoporosis, cancer and other age-related diseases.

Born in Kenya, he lived an active life — including siring offspring — until early Thanksgiving morning, when his body was discovered in a lab at the Barshop Institute for Longevity and Aging Studies on the campus of the Texas Research Park in Bexar County.

A naked mole rat, Old Man was believed to be 32.

Often called the ugliest animals on the planet, naked mole rats are positively beautiful in the eyes of researchers on aging such as Rochelle Buffenstein, a professor in the department of physiology.

"In many ways, they confound what scientists think they know about how diseases progress and why living things age," she said.

The Barshop Institute, part of the University of Texas Health Science Center, maintains the world's largest mole rat colony. About 2,000 of the tiny, burrowing rodents whose most distinctive feature is their sharp, protruding teeth, live and breed in four basement labs. With their long, hairless bodies and translucent pink skin, they look a bit like Vietnamese spring rolls with legs.

Because these natives of East Africa live an average 26 years (compared to the 2- to 4-year lifespan of other rodents), they're well suited for studies of age-related disease. For example, older mole rats develop the same type of brain plaque found in Alzheimer's patients. But for reasons unknown, they don't experience similar cognitive decline.

Their bones also stay strong and healthy well into their later years.

And perhaps most intriguing, mole rats very rarely develop cancer - a common cause of death among other rodents. In fact, when immune-suppressed mice were injected with naked mole rat cells containing tumor-forming genes, they didn't develop cancer.

Among the many mole rats at the institute, however, Old Man stood out. Because of his advanced age and vigor, he'd claimed a special place in the hearts of many researchers. Laboratory animal attendant Cody Villanueva discovered his body early Thanksgiving morning.

"Oh, it was a sad day," she recalled. "I cried. We all did."

Old Man was thought to be 1½ to 2 years old in 1980 when he and 75 of his naked mole rat brethren were captured in a Kenyan sweet potato field - sweet potatoes being one of the mole rat's favorite dishes.

Buffenstein brought him first to the University of Cape Town in South Africa, and then to City College of New York in Harlem. The pair arrived in San Antonio in 2007.

Like other mole rat colonies, Old Man's was led by a female queen who breeds with up to four males.

"Mole rats are a lot like bees in their social structure," Buffenstein explained. "When the queen dies, the other females in the colony will fight to the death to succeed her."

Even in his old age, Old Man remained an alpha male in his colony. Come feeding time, Old Man was served a special cereal that he loved and that Buffenstein imported from South Africa.

"He'd wrap his body around the bowl and eat until he was full," she said. "The other rats would wait until he was finished before they ate."

He also continued to mate with the colony's breeding female right to the end. About the only outward sign of his advancing age was the sarcopenia, or loss of muscle mass, he developed about five years ago.

The cause of Old Man's death remains uncertain.

"We know he didn't die of cancer," said Buffenstein. "It may have been something cardiovascular."

A necropsy has been performed and tissue samples have been sent to the institute's pathology lab for evaluation.

Buffenstein expects that, even in death, Old Man will help advance the state of scientific knowledge.

rmarini@express-news.net