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The Daily Vet by petMD

The Daily Vet is a blog featuring veterinarians from all walks of life. Every week they will tackle entertaining, interesting, and sometimes difficult topics in the world of animal medicine – all in the hopes that their unique insights and personal experiences will help you to understand your pets.

Dogs Have Superpowers Even Beyond Their Noses

Dogs, for all their familiar, comforting, domesticated presence in our homes, remain to me mysterious creatures. How an animal can predict epilepsy at one turn like some ethereal body scanner and drink out of the toilet the next moment is one of the great paradoxes of the universe; this capacity for strange miracles comingled with the banal. 


Some of the mystery surrounding dogs’ unusual prowess in sensing disease resides in their noses. The canine nose is thought to be between 10,000 and 100,000 times more sensitive than the human nose. In addition, a greater portion of their brain is dedicated to interpreting this massive amount of data.


Given their aptitude to experience the world through their noses, it’s no surprise than among the many things dogs can sniff out, cancer is one of them. Dogs have been trained to correctly identify lung cancer on the breath, colon cancer in the stool, and bladder cancer in the urine.


While we know dogs have been able to correctly identify the difference between ill patients and well ones, we still haven’t been able to isolate exactly what it is the dogs are smelling; inflammatory mediators, necrosis, or benzene derivatives secreted by cancer cells? Perhaps we’ll figure it out one day, but for now we can simply revel in the marvel of the idea of a dog breath-sniffer one day replacing the dreaded mammogram or colonoscopy.


In a 2006 study in Integrative Cancer Therapy, dogs from Guide Dogs for the Blind were able to identify breast cancer patients 88 percent of the time. Until they were trained to identify the smell of cancer, these dogs had completed only basic obedience training, meaning this sort of sniff sensitivity isn’t limited just to certain “supersniffer” canines.


My mother, who loves all of my dogs, remarked earlier this year that she had a special bond with my current pup Brody. It’s true, he lavishes love on everyone, but it seemed like he had a special attachment to her.


Three weeks ago she was diagnosed with a malignant glioblastoma, one of the most aggressive forms of cancer and the worst of all the brain cancers. We all realized that Brody knew well before the rest of us did.


We have no way to explain “this person has terminal cancer” to a dog the way we can to another person, no words we can use to get them to understand what is happening to their human. We don’t need to. In the time since the diagnosis, my parents have been staying with me. My dog, who has spent every night of his life sleeping by my bedside, hasn’t left her side. He sleeps at her feet at night, lays his head on her by the couch by day, and licks her toes whenever a medical person stops by to check on her.


“He’s my natural Xanax,” Mom says, and we laugh, but it’s true. Of all the gifts dogs have to offer, that is still the greatest one of them all. 



Dr. Jessica Vogelsang



Image: Annette Shaff / Shutterstock


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