Our Better Nature: Do Animals Have Feelings Too?

If you’ve ever had a dog, you know how obvious it is that they’re happy to see you when you come home. And yet for many years, scientists warned us not to anthropomorphize, or assign human feelings to animals. We were told we were likely to misinterpret their behaviors, and also that animals were incapable of real emotion.

These days, we’re still advised to use caution when comparing an animal’s motives to our own, but biologists have made a complete reversal on the question of animal emotions. It turns out pet owners were right all along: Many animals experience a range of feelings, including joy, fear, grief, and compassion.

It’s important to note that biologists do not equate animals’ lives with ours. No one in the scientific world is saying that other animals feel happiness or sorrow the way humans do. It’s just that evidence shows that animals do feel. For example, most vertebrate species play throughout their lives for the sheer fun of it, not merely as a juvenile adaptation. At least 65 animal species are known to laugh out loud to denote happiness, and some have even evolved a complex sense of humor.

A chimpanzee laughing (Uploaded to YouTube by BBC)

Non-human species feel negative emotions as well. Research strongly suggests that many animals, especially social ones, mourn the loss of a group member. In fact, there is a branch of science called evolutionary thanatology that studies how social species, including our own, respond to death and loss from an evolutionary perspective.

It’s no surprise that our primate cousins like chimps, apes, and monkeys keenly mourn the loss of their loved ones. And elephants are renowned for their highly choreographed death rituals, often lasting days, when a herd member passes.

But we don’t have to go far from home to see this kind of performance. Crows hold elaborate “funerals” for their dead, gathering in large numbers around a fallen peer, guarding the corpse from predators. Studies also show that ravens can feel empathy for grieving comrades.

A crow “funeral” (Uploaded to YouTube by Adam Molina)

We know that marine mammals react strongly to the loss of their young. In 2018, an orca off the coast of Seattle was seen carrying her dead calf on the surface for 17 straight days. At least a dozen cases of dolphins behaving similarly after the death of an offspring have been documented, and mother whales have been observed risking starvation to stay by the side of a dead calf.

An orca was seen carrying her dead calf for 17 straight days (Uploaded to YouTube by CBC News: The National)

One of the most unlikely species to react to death within their group may end up being the most helpful to us in terms of healing from loss. A recent discovery made by University of Michigan scientists about the brain chemistry of fruit flies could point to new ways of treating trauma in humans. The 2023 study showed that fruit flies exposed to numerous fly corpses (“an excess of dead flies,” in the authors’ words) of the same species had significantly shorter lifespans as compared to the unexposed group.

This mirrors what can happen to people as well. Grief does more than just affect us psychologically. It hits physically as well, raising the risk of heart disease threefold and making us nearly four times more likely to have an early death from all causes across the board.

This is not intended to compare human anguish wrought by loss and the neurological responses in the primitive brain of a fly that views its dead peers. The researchers make it clear their work is not to find a window into the human experience through fruit flies, but to “…provide insight for treating individuals who are routinely exposed to stressful situations surrounding death…”

Fruit flies were chosen for their simple brains, which made it easier for researchers to fluorescently tag individual neurons. They were thus able to identify and track chemical changes that resulted from exposure to dead flies. Also, fruit flies are economical to study – they breed like, well, flies.

When flies were shown a bunch of dead compatriots (in a sealed chamber, to rule out smell as a trigger), it activated serotonin 5-HT2A receptors on select neurons. As strange as it might sound, the serotonin 5-HT2A receptors on fly brain cells are identical to the ones located on human brain cells. In people, these receptors control a number of things, including muscle movement and memory formation.

If scientists can locate the specific neurons activated by trauma and find a safe way of silencing the 5-HT2A receptors on those neurons exclusively, it would be a huge step toward helping us understand our response to traumatic loss. Specifically, it could help the small subset of people who can’t seem to move on from grief, developing what is known as “persistent complex bereavement disorder.”

Science has proven that dogs sense when we’re sad and will seek us out to comfort us.  Now it seems a very different animal may be a key to helping us move beyond persistent grief.