Selkie the gray seal lives on the American Trail exhibit at the National Zoo in Washington. She’s 43 years old and can’t see. (Mark Van Bergh/Smithsonian Institution)

Selkie the gray seal rips a silvery hunk of butterfish in half, gulps it down and looks to her keeper for more. Allie Killam, who cares for Selkie and other animals on the American Trail exhibit at the Smithsonian’s National Zoo, drops a slippery squid into the seal’s open mouth. Her teeth are worn with age. Cataracts cloud her eyes. She can’t see, but Selkie, 43, slurps the slimy stuff with ease. When she hears Killam tap the empty metal bucket against the edge of the pool, the seal knows chow time is over. She slips back into her pool with hardly a splash.

Maintaining Selkie’s ample weight and communicating through sound and touch are two ways that keepers care for the zoo’s eldest seal. She also gets dietary supplements and regular medical care. To make life easy, her exhibit includes ramps and steps so she can “haul out” of her pool without overexerting herself.

Zoos all over the world provide special care for elderly residents, such as an elderly gorilla at a zoo in Illinois whose keepers provide human medicine to ease aching joints. Like Selkie, these animals are cherished ambassadors who educate the public about their species.

Rob Vernon, a spokesman for the Association of Zoos & Aquariums (AZA) in Silver Spring, Maryland, says that through years of work, zoos have found ways to change habitats and nutrition and veterinary health programs to benefit older animals.

“Professional caretakers, like zookeepers and veterinarians, at AZA-accredited zoos are passionate and compassionate about the animals they care for,” he said in an email.

Dorothy, a 58-year-old Cuban crocodile at the National Zoo’s Reptile Discovery Center. There may be fewer than 3,000 Cuban crocs in the wild today, so every egg she lays counts. (Jacquelyn Martin/Associated Press)

In the wild, life for an animal such as Selkie would be much different. And, on average, much shorter. A gray seal in the wild might live to be 20 or 25 years old. It would have to hunt for food and dodge predators such as sharks and killer whales.

In captivity, some elderly animals are helping to save their species, such as a 58-year-old Cuban crocodile named Dorothy, who lives in the National Zoo’s Reptile Discovery Center. There may be fewer than 3,000 Cuban crocodiles left in the wild today. Every egg Dorothy lays could turn into an important, healthy hatchling. In 2012, Dorothy hatched two green-and-gold-speckled Cuban croc babies. Last year, she hatched five. She may lay eggs again next month.

To keep this species-saving mom in top condition, keeper Lauren Augustine hides calcium supplements in the whole rabbits, chickens and fish carcasses that Dorothy eats. Augustine also keeps a sharp eye on behavior of all the naturally aggressive, territorial crocs in the exhibit to make sure they’re getting along.

For both Dorothy and Selkie (grandma to Rona, one of the zoo’s younger gray seals), the days are generally quiet. “At her age, Selkie just wants to relax and have food put in her face,” Killam says. “We just want to set her up for success.”

Meet the Animals

You can visit and learn from elderly zoo animals across the country.

●Selkie, a 43-year-old gray seal, lives on the American Trail exhibit at the Smithsonian’s National Zoo.

●Dorothy, a 58-year-old Cuban crocodile, lives at the National Zoo’s Reptile Discovery Center.

●Ramar the gorilla, who is at least 48, lives at the Brookfield Zoo in Brookfield, Illinois.

●Mek Degong the Malayan tiger is 18. She gave birth to four cubs in 2014 at the Fresno Chaffee Zoo in California.

●Packy, an Asian elephant at the Oregon Zoo in Portland, Oregon, turned 54 on April 14. He’s the oldest male Asian elephant in North America.