Do Cats Know When You’re Sick or Dying?

In 2007, geriatrician David Dosa described an unusual resident of the Steere House Nursing and Rehabilitation Center in Providence, Rhode Island, in the New England Journal of Medicine.

Oscar was a cat living on an advanced dementia ward. According to Dosa and the nursing staff, Oscar usually kept to himself. But when a resident was approaching death, he would sometimes enter the room, climb onto the bed and remain beside the patient.

The behaviour became sufficiently consistent that staff began treating Oscar’s choice of sleeping companion as a reason to contact relatives. Dosa initially described around 25 cases; later accounts associated with his follow-up work put the number considerably higher.

Oscar was not conducting a blinded clinical trial, naturally. He was a cat with an inconveniently dramatic bedside manner.

What was he detecting?

Death Changes a Living Body Before It Stops

One possibility is smell.

Cats possess a highly developed olfactory system and use scent extensively when identifying their surroundings and other individuals. Recent experiments have shown that domestic cats can distinguish familiar from unfamiliar humans using odour alone.

There is also evidence that cats respond differently to human body odours associated with different emotional states. In one experiment, cats exposed to odours collected from frightened humans behaved differently from those presented with neutral or physically stressed human odours.

If fear or stress alters human chemical signals enough for cats to notice, what happens during severe illness?

Metabolism changes. Medication changes. Breathing changes. People eat and move differently. Body temperature and circulation can change. Near the end of life, several of these things may be happening simultaneously.

Could Oscar have learned a particular smell associated with dying patients?

Dosa himself considered that possibility. Another suggestion was that he recognised reduced movement or other changes in behaviour. The curious part is that nobody identified the precise signal he appeared to be following.

Cats Notice More About Us Than They Let On

Cats are not merely smelling furniture while pretending not to care whether we exist.

Experiments have found that they can distinguish human emotional cues and can combine information from voices and faces. Other research suggests that cats modify their behaviour after observing an owner’s emotional response to something unfamiliar.

That makes the idea that a cat could notice illness considerably less mysterious at the first level.

If somebody suddenly smells different, breathes differently, moves differently and behaves differently, the cat may possess more information than another human entering the room for thirty seconds.

But does recognising illness explain recognising death several hours before it occurs?

That is where Oscar remains interesting.

Perhaps the final stages of dying produce a recognisable combination of chemical and behavioural signals. Perhaps a cat living permanently among severely ill patients learns that pattern through experience.

Or perhaps there was something else in the sequence nobody thought to measure.

And Then There Is the Purr

Cats contribute another strange piece to the story themselves.

Their purr is unusually low for an animal of their size. Modern anatomical research has found that feline vocal folds can naturally produce frequencies around 25 to 30 Hz, helping explain the characteristic low-frequency vibration.

An older study of several felid species found prominent purr frequencies across roughly 25 to 150 Hz and proposed an interesting possibility: some of those frequencies overlap with ranges investigated in therapeutic mechanical vibration for bone, muscle and tissue effects. The author asked whether purring might therefore provide cats with some kind of internal mechanical benefit.

It remains a hypothesis rather than evidence that putting a tabby on your chest constitutes advanced regenerative medicine. That particular leap has enjoyed a much more energetic life online than in clinical research.

Still, the question itself is odd enough.

Why do cats produce sustained low-frequency vibrations at all, and why do they sometimes purr in contexts other than obvious contentment?

Could the vibration affect the cat itself? Could it also affect another animal resting against it?

Why Sit Beside the Dying?

There is another possibility that has nothing to do with predicting death.

A very sick person is quiet.

They remain still for long periods. Their bed is warm. The room may become calmer. Family members and carers behave differently. All of that could make the location attractive to a cat.

But Oscar reportedly selected particular patients while ignoring others on the same ward, sometimes remaining with them until death.

Was he detecting the physiological process of dying, or merely responding to a set of environmental cues that happened to accompany it?

From the cat’s perspective, those may not even be different questions.

Do Cats Know?

Perhaps “know” is the difficult word.

A cat does not need a concept of terminal illness to recognise that something profound has changed in a familiar human body. It may smell what we cannot smell, notice changes we overlook and connect those signals with previous experience.

Whether Oscar understood that the person beside him was going to die is something nobody can extract from his behaviour alone.

But the behaviour happened often enough that experienced nursing staff began paying attention to it.

A cat walked into a room, chose a bed and settled beside someone.

The humans eventually learned that when he did, they might want to call the family.

What Oscar knew during those final hours remains his part of the story.