This is from a CNN news item:
"After Babs the gorilla died at age 30, keepers at Brookfield Zoo decided to allow surviving gorillas to mourn the most influential female in their social family....Babs' 9-year-old daughter, Bana, was the first to approach the body, followed by Babs' mother, Alpha, 43. Bana sat down, held Babs' hand and stroked her mother's stomach. Then she sat down and laid her head on Babs' arm."
There's apparently no question they understood she was dead, and were acknowledging her in some way, for whatever reason.
While I have very little in common with animal-rights people in general, my perspective changes dramatically when we're talking about intelligent animals. Considering gorillas to be the moral equivalent of cows or fish is a huge mistake. Maybe considering cows to be the moral equivalent of fish is also a mistake - I'm not sure. But wherever the line is drawn, the great apes and possibly a number of other animals should be on the side where we treat them more like people and less like chattel.