“Children, in particular, have a distinct sense of existential fairness around whether or not an animal lived until an appropriate age,” Dr. Russell said.

Image Reading age-appropriate books about a pet’s death, like this one for ages 4 to 8, may be helpful in getting a child over the grief. Credit... APA

Like adults, children more readily accepted their pet’s death when it was expected in some way. For example, children were less affected when they knew in advance that the animal would have a short life span. They seemed to know that a fish or hamster, for instance, would not live as long as a dog or cat. When an animal was sick, they generally agreed that euthanasia relieved the pet of its suffering. If an animal is terminally ill, parents can help prepare the child by talking about the impending loss, as well as the feelings of sadness it will evoke.

Yet when pets died in tragic and unexpected ways, the loss was harder for the child to accept. “When a pet dies suddenly, it highlights the unpredictability of the world. It tells children that the people and animals they love can die without warning,” said Abigail Marks, a clinical psychologist in San Francisco who specializes in childhood grief.

Of course, a child’s age and developmental level affect how he or she understands death, and a child’s grief looks very different from an adult’s. Children do not always cry or immediately show emotion. But this does not mean they are not deeply affected by the loss.

“Kids under the age of 5 will have a hard time understanding that the pet is gone forever because it’s difficult for them to grasp the concept of death,” said Jessica Harvey, a psychotherapist in San Francisco who specializes in pet grief.