Here is how gorillas grieve:

Gorillas are known to hold wakes for dead friends, something that some zoos have formalized in a ceremony when one of their gorillas passes away. Donna Fernandes, now president of the Buffalo Zoo, tells the story of being at Boston's Franklin Park Zoo ten years ago during the wake for a female gorilla, Babs, who had died of cancer. She describes seeing the gorilla's longtime mate say good-bye: "He was howling and banging his chest,... and he picked up a piece of her favorite food — celery — and put it in her hand and tried to get her to wake up. I was weeping, it was so emotional." Later, the scene at Babs's December funeral was similarly moving. As reported by local news, gorilla family members "one by one ... filed into" the room where "Babs's body lay," approaching their "beloved leader" and "gently sniffing the body."

Here is how elephants express their grief:

[These] are the actions of the members of an elephant family... after a group member had been shot: "Teresia and Trista became frantic and knelt down and tried to lift her up. They worked their tusks under her back and under her head. At one point they succeeded in lifting her into a sitting position but her body flopped back down. Her family tried everything to rouse her, kicking and tusking her, and Tullulah even went off and collected a trunkful of grass and tried to stuff it in her mouth."

Finally, wolves:

[A] wolf pack after the loss of the low-ranking omega female wolf, Motaki, to a mountain lion. The pack lost their spirit and their playfulness. They no longer howled as a group, but rather they "sang alone in a slow mournful cry." They were depressed — tails and heads held low and walking softly and slowly — when they came upon the place where Motaki was killed. They inspected the area and pinned their ears back and dropped their tails, a gesture that usually means submission. It took about six weeks for the pack to return to normal. The Dutchers also tell of a wolf pack in Canada in which one pack member died and the others wandered about in a figure eight as if searching for her. They also howled long and mournfully.

As for humans, some of us can completely contain our emotions and turn the grief into a dark, inner sea that's wide and deep. We know the depths of death. No crying, no smelling, no stomping about—just the silent sea of grief.