Researchers at the University of Cambridge’s Department of Veterinary Medicine discovered that male dogs, especially free roaming dogs, were four to five times likely to develop the Oro-nasal form of Canine Transmissible Venereal Tumors (CTVT) than female dogs.

CTVT is an unusual cancer that can spread between dogs that come in contact. This type of cancer is infectious because the living cancer cells can be physically transplanted from one animal to another. The researchers feel that the reason it is more prevalent in male dogs is because they spend more time sniffing and licking female dog genitalia.

The common symptoms are difficulty breathing, nasal deformation or bloody or other discharge from the nose and/or mouth. Fortunately, this type of cancer is treatable with Vincristine chemotherapy.  

The researchers noted that transmissible cancers are found in Tasmanian Devils as well as marine bivalves such as mussels and clams.