A themograph highlighting the hot and cold portions of a dog’s face with its cold nose and very hot tongue/Scientific Reports

Add FLIR – or something resembling it – to the amazing powers of a dogs’ nose.

Military members and those familiar with Alaska Search and Rescue will immediately recognize the acronym for “forward looking infrared” imaging. FLIR is the “heat-seeking” technology that allows people in aircraft to detect warm objects against cold ground.

Dogs, according to new research, possess a similar natural ability although the extent of its range at this point remains unclear.

Still, Anna Bálint from Sweden’s Lund University along with colleagues from Hungary and Sweden, are reporting they have documented the ability of dogs to do more with their nose than smell.

They can also use it to find warm bodies.

“It is unclear how thermal radiation is transduced in the dog rhinarium,” the naked and often most skin on the tip of a dog’s nose, their peer-reviewed study published Scientific Reports said. But researchers could detect a clear response to heat in the brains of the dogs they tested, and they could train the animals to find objects by looking for heat instead of scent.

Animal powers

Noting the cold noses of dogs as compared to the noses of herbivores or, for that matter humans, they theorized that “this coldness makes the dog rhinarium particularly sensitive to radiating heat. (And) we trained three dogs to distinguish between two distant objects based on radiating heat.”

Dogs trained to look for heated panels in order to earn a reward ignored panels at room temperature, but reacted to those with “about the same surface temperature as a furry mammal,” the study said. “In addition, we employed functional magnetic resonance imaging (MRI) on 13 awake dogs, comparing the responses to heat stimuli of about the same temperatures as in the behavioral experiment. The warm stimulus elicited increased neural response in the left somatosensory association cortex.”

The ability to sense heat has previously been documented in other animals, notable insects bats and especially snakes which can detect “temperature changes as small as 0.001 degrees, possibly even smaller,” as the researchers noted.

How snakes are able to do this remains unclear. Thermal radiation is emitted at very low energies, but hungry snakes can track it well enough to find prey as can some insects and bats.

“Crotaline snakes can strike at prey guided exclusively by the thermal radiation emanating from a warm body,” the researchers observed, and the ability to detect radiation from warm bodies could be advantageous to wolves, the closest wild relative of the domestic dogs.

The common vampire bat uses its nose to detect skin areas richest with warm blood before chomping into its prey.

“The sensitive area in vampire bats is also in the nasal region and it is also somewhat colder than other parts of the face,” the researchers noted.

Dogs appear to heat-sensing abilities similar to bats, but a lot remains to be discovered about the range of their thermal-sensing.

How powerful?

“Determining thresholds at various ambient temperatures, with various rhinarium temperatures, for different stimulus sizes, distances, and temperatures requires further studies,” the researchers noted. “In this investigation, we used dogs of various breeds and sizes as well as two different experimental approaches and found that sensing weak thermal radiation is within the abilities of the species….The limits and mechanisms of this ability remain to be” defined.

The study does raise some interesting questions about the ability of dogs to “smell” various cancers, an ability for which they have become somewhat well known.

“Dogs have an incredibly sensitive sense of smell that can detect the odor signatures of various types of cancer. Among others, they can detect colon cancer, prostate cancer, breast cancer, and melanoma by sniffing people’s skin, bodily fluids, or breath,” Medical News Today reports.

What those cancers smell like no ones knows because humans lack the olfactory abilities of dogs. But some of those cancers,  melanoma being one, are known to have heat signatures.

Breast cancer is another. A thermal imaging museum in Scotland – the Camera Obscura & World of Illusions in Edinburgh – made the news big time last year when a woman making a thermal image of herself spotted hot spots.

“Thinking the uneven heat was ‘odd’ compared to other people, Ms. (Bal) Gill carried out an internet search on thermal imaging cameras and found out they can be used by oncologists to help diagnose cancers,” The Telegraph reported in October. 

The internet research led her to make an appointment with her doctor.

“The 41-year-old, from Slough in Berkshire, was diagnosed with breast cancer at the ‘really early stages’ and is now waiting for a third operation to try to prevent the disease from spreading,” the newspaper reported.