Gus, one of the oldest male Asian small-clawed otters in North American zoos, has died at the Columbus Zoo and Aquarium in Powell.

The zoo announced Saturday, Aug. 29, that Gus was nearly 18 years old. Male Asian small-clawed otters in captivity have a median life expectancy of 14.7 years, according to the zoo. Gus exceeded that by more than three years.

The zoo's animal care and conservation medicine teams chose humane euthanasia after Gus's health declined from age-related conditions, 10TV first reported. The zoo said his wellbeing and quality of life guided every decision.

Gus arrived in Powell in 2014 at age 5. He was paired with a female named Peanut, and together they raised two litters. The zoo said the pair stayed closely bonded throughout their years together.

Asian small-clawed otters are the smallest of all 13 otter species, weighing less than 10 pounds and measuring up to two feet long, according to the Smithsonian's National Zoo. The Smithsonian notes the species can live up to 12 years in human care, though some individuals have surpassed 20. Gus's nearly 18 years placed him well above the typical range.

As Gus aged, his care shifted to address conditions common in older otters. That process helped zoo staff and other zoological organizations learn how to care for geriatric members of the species. The zoo said the knowledge Gus provided will shape animal care for years to come.

The species faces threats including habitat loss and the illegal pet trade. Gus served as an ambassador at the zoo, teaching guests about Asian small-clawed otters and the resources required to keep them healthy.

During his final days, caregivers filled Gus's living spaces with things he loved: hay, straw, wood wool and shavings.

In a Facebook post, the zoo said Gus left his mark over nearly 18 years and that his legacy would extend well beyond his own lifetime.

He leaves behind his mate Peanut and generations of offspring at the zoo.