06/25/2012 02:27 pm ET Updated Jun 25, 2012

Gunnar Dead: National Zoo's Elderly Gray Seal And Veteran Of The Navy's Marine Mammal Program Dies At Age 38 (PHOTOS)

WASHINGTON -- Gunnar, the Smithsonian National Zoo's elderly gray seal who died on Friday, did not lead a boring life.

Gunnar spent his early life as part of the U.S. Navy's marine mammal program -- that's a program that studies the use of marine mammals, like dolphins and seals, in the military.

Dolphins have been taught to do things like detect mines, identify enemy swimmers and escort oil tankers through the Persian Gulf. And some people believe dolphins have also been trained to shoot guns.

The Navy taught Gunnar and Selkie, the Zoo's two gray seals, both born in 1973 and captured in Iceland at about six months old, to use screwdrivers and to perform underwater tasks.

Gunnar The Gray Seal

But they didn't last long in the military, according to a 2008 Zoogoer article:

The gray seals were taught how to retrieve items, insert and remove equipment, use a screwdriver, and even turn a large wheel valve. Eventually, seals were dropped from the training program, in part because they were not as consistent in their performance as other animals, such as California sea lions and bottlenose dolphins -- which are still used today. One Navy trainer specifically remembers the Zoo’s female seal, Selkie, because of her distinctive behavior. He would take her by boat for an ocean training session. Sometimes she’d put her head in, enter the water, and practice her skills. Other times, she would pull her head back out of the water and stay put -- which meant she wouldn’t cooperate, so he would simply give up and head back to shore with her.

Gunnar and Selkie came to the National Zoo in 1979, and had two babies in the ensuing years; the pups were sent to live at an aquarium in Camden, N.J.

The 2008 Zoogoer article quotes Linda Moore, a National Zoo biologist, as saying that Selkie "still displays some of the skills she learned" in the Navy, but Gunnar's displays were more rare and unexpected:

Moore was surprised recently when Gunnar displayed his problemsolving abilities -- perhaps instilled from his Navy days. When Moore was feeding Gunnar, one fish dropped to the bottom of the pool and disappeared under the drain grate. Moore showed Gunnar the empty fish bucket, which is how keepers indicate a feeding is over. She planned to then go flush the fallen fish out of the drain -- but noticed Gunnar swimming toward the drain. “He took his front flipper and began waving it rapidly over the grate. Suddenly the fish popped up out of the grate and Gunnar ate it! This was obviously something he had figured out how to do on his own, and it didn’t appear to be the first time he had done it.”

Gunnar was 38 years old when he died. The zoo said in a statement that his health was in decline for several months before he died.

Selkie is alive but no longer on display at the zoo. Gunnar and Selkie's two pups, Kara and Kjia, will soon leave New Jersey to come back home -- they're scheduled to return to the National Zoo in the fall as part of the new American Trail exhibit.