Dogs Can Smell Cancer in Other Dogs: What It Means for Owners

Home » Latest news » Dogs Can Smell Cancer in Other Dogs: What It Means for Owners

Dogs’ sense of smell has long been celebrated, from sniffing out missing persons to detecting diseases in humans. Now, research published in Veterinary Oncology reveals that dogs can also detect cancer in their canine peers. By studying behavioural responses to urine samples from both healthy and cancer-affected dogs, the researchers have provided new insights into how this innate ability might function. The findings have significant implications for multi-dog or multi-species households and the broader potential for dogs to contribute to veterinary and human healthcare.

Overview of the study

The study by Desmas-Bazelle et al. (2024) involved 30 dogs of various breeds, none of which had been trained specifically for cancer detection. These dogs were presented with urine samples from a group of 10 other dogs, half of whom had been diagnosed with cancer. Each trial exposed the participants to a mix of samples, allowing the researchers to observe their sniffing behaviour and preferences.

The dogs consistently demonstrated a stronger interest in samples from cancer-affected dogs. They spent more time investigating these samples, showing behaviours that suggested an ability to identify unique chemical markers associated with cancer. The controlled setup, while relatively simple, provided compelling evidence for this olfactory ability across different breeds and age groups.

The results confirmed that dogs can reliably differentiate between cancerous and healthy samples, even without training. This suggests that their ability to detect illness might be innate rather than learned, highlighting just how remarkable their sense of smell is.

For dog guardians, particularly those with multiple pets, this discovery offers a potential explanation for behaviours often observed in multi-dog households. Increased sniffing, attentiveness, avoidance of a sick companion or even aggressive responses towards the other dog could stem from their ability to detect health-related odours. Anecdotally, in a number of cases I have worked on over the years where there has been a disruption to a previously harmonious relationship between dogs (and cats), I have recommended that animal being targeted is also examined by the veterinary surgeon; a common theme in these cases was that other pet then being diagnosed with a health-related issue. While a dog’s ability to detect scent alterations in another isn’t a substitute for veterinary care, awareness of dogs’ abilities might serve as an ‘early warning’ system, encouraging owners to seek professional advice.

As with all studies, there are some limitations to this research. Firstly, the sample size of 10 urine donors and 30 canine participants, while significant for a behavioural experiment, is relatively small for drawing broad conclusions. Secondly, the controlled environment of the study does not reflect real-world conditions; in our households and other contexts, there are competing odours and distractions that could impact a dog’s ability to detect illness via chemical scent changes. The specific compounds dogs are identifying in cancerous samples also remain unknown, leaving the exact mechanisms behind their behaviour unclear.

Nevertheless, this research opens the door to further exploration of dogs’ olfactory capabilities. Identifying the precise chemical markers linked to cancer would be a critical next step, enabling the development of non-invasive diagnostic tools for animals and humans alike. Additionally, future studies could examine whether environmental factors, breed-specific traits, or age influence detection accuracy. Understanding the social and emotional dynamics of how dogs respond to illness in their companions could also deepen our knowledge of their behaviour.

Key take-away

For dog guardians, these findings underscore the importance of paying attention to subtle behavioural changes in multi-dog or multi-species households. A healthy dog showing unusual interest, concern or onset of new aggressive responses for another may be picking up on health-related odours. While these observations do not replace veterinary diagnostics, they can prompt earlier interventions and improve outcomes for sick pets.

Reference

• Desmas-Bazelle, I., Rooney, N.J., Morant, S. et al. Trained dogs can detect canine urothelial carcinoma of the bladder. Vet. Oncol. 1, 12 (2024). https://doi.org/10.1186/s44356-024-00012-1.