By Nan Talleno

PHILADELPHIA (CBS) – Dogs certainly do have plenty of personality and, like humans, they experience a great deal of emotions like love, grief, fear, sadness, loneliness, pain, excitement, and joy.

In 1996, the American Society for the Prevention of Cruelty to Animals conducted a Companion Animal Mourning Project which found that 66% of dogs exhibited four or more behavioral changes after losing a pet companion.

Dogs certainly do grieve after a loss. They display signs of depression, anxiety, fear, loss of appetite and change in sleep pattern.

In Austria, a researcher from the University of Vienna discovered that dogs adhere to a sense of “fair play” while experimenting with a large group of dogs. Rewarding only several dogs with treats while all of the dogs were asked to perform the “shake” command and “give their paw.” When a majority of the dogs became aware that only several dogs were receiving treats, those dogs immediately stopped the activity.

From their ancestry of the wolf down to the domestic dog, canines, being pack animals, are truly loyal to their pack, nurture their young and sick, greet each other, interact socially, enjoy companionship, warn each other of danger and ultimately protect the pack.