Why does the loss of a pet hurt so much?

People are deeply affected by significant losses, and the loss of a pet is no exception. Although the ways in which we relate to grief differ between individuals and cultures, contemporary research increasingly shows that grieving for a pet is a real, complex, and legitimate emotional experience.

For many people, the pain is accompanied by a troubling question:

"Why does it hurt so much?"

Sometimes this pain is comparable to or even more intense than that experienced after the loss of a loved one, and the reactions of those around us – "it was just a dog," "you'll get another one" – can deepen feelings of guilt, shame, and isolation.

In recent years, scientific research has begun to confirm what many people already knew from experience: the human-animal bond is deep, real, and biologically supported.

What attachment psychology and neuroscience say

The human-animal bond means attachment, a psychological and neurobiological process. Studies in attachment psychology show that a dog can become an attachment figure for an adult, fulfilling essential functions such as:

• a secure base

• an emotional refuge (safe haven)

• a constant presence in daily emotional regulation

Psychologist Lawrence Kurdek (2009) showed that, in times of emotional distress, some owners turn to their dogs for support more often than to their parents, siblings, or friends, with the exception of their romantic partners.

This bond involves:

• stress regulation

• a sense of belonging

• activation of attachment systems in the brain

In addition, the degree of attachment between humans and pets directly influences the psychological impact of loss (Cowles, 2016).

Oxytocin, emotional regulation, and sudden absence

Oxytocin, often called the "attachment hormone," plays an important role in the human-animal relationship. Numerous studies suggest that positive interactions—eye contact, petting, playing—may be associated with changes in oxytocin levels in both humans and dogs.

However, the research remains nuanced, not idealized. For example, Marshall-Pescini et al. (2019) highlight mixed results, emphasizing the importance of relationship quality, interaction context, and methodology used.

Not every interaction automatically produces oxytocin, but close relationships can, over time, become stable systems of emotional regulation. When a pet dies, these circuits are left without their "partner," and the brain is forced to reorganize itself. As a consequence of this reasoning, the following may occur:

• a feeling of physical emptiness

• disorientation

• anxiety

• a longing that is not only emotional, but also physical

What does neuroscience tell us about brains on the same wavelength?

A study published in Advanced Science (Ren et al., 2024) showed that when a human and their dog interact by looking at each other or petting each other, there is a synchronization of brain activity between the two.

This synchronization of neural activity (interbrain coupling) occurs in the frontal and parietal regions, increases with familiarity between humans and dogs, and suggests a form of neural communication between species.

In short, the human-dog relationship is not only emotional, but also neurobiologically synchronized. When this relationship ends in death, it is not just a "companion" that is lost, but a daily co-regulation of the brain and body.

Why is pet loss grief often invisible?

Disenfranchised grief and ambiguous loss

Research on dog theft (Roberts et al.; Walliss et al., 2025) shows that:

• the bond with a pet is often equivalent to family relationships

• the suffering is intense but socially minimized

• disenfranchised grief frequently occurs

The same thing happens after the death of a pet. The pain is real, but it does not receive social recognition, which makes it more difficult to process and integrate.

Research shows that the severity of grief is comparable to that of losing a loved one

Studies indicate that grief reactions after the loss of a pet can be similar in intensity and duration to those that occur after the loss of a person.

• A 2009 study showed that for about 30% of respondents, pain and sadness persisted for six months or more after the death of the animal.

• Research conducted in Australia in 2018 found no significant differences between the grief of people who lost a pet and those who lost a loved one.

• It was highlighted that animal lovers have the tendency to humanize pets and have a negative outlook on life after the loss of their pets (Uccedut et al., 2019).

A comprehensive study published in PLOS ONE (Hyland, 2026) showed that:

• 7.5% of people who have lost a pet meet the criteria for prolonged grief disorder (PGD)

• the symptoms are similar to those experienced after the loss of a person

• over 20% of respondents considered the loss of their pet more painful than the loss of a loved one

All of this information supports clinical observations that grief for a pet can be profound and long-lasting. This does not mean that everyone will need therapy, but clinical recognition and psychological support can be helpful when the suffering is intense and does not subside over time.

What does all this mean for you if you are grieving?

Grief after the loss of a pet is not just temporary sadness, but a complex, valid, and often intense emotional reaction. Scientific studies confirm what many people feel deeply. The pain can be real, strong, and sometimes long-lasting. It occurs because:

• you had a real attachment relationship

• your brain and body have been tuned in to this connection for years

• the loss is not only emotional but also neurobiological

Therefore, mourning for a pet is a natural human reaction to the loss of a meaningful relationship. Accepting this reality and receiving the right support (whether through therapy, support groups, or empathetic connections) influences how this experience is navigated.