Posted by Dr. Pamela Barker

Discovering an unusual growth on your pet’s body can be a scary experience. With so much media attention devoted to the dangers of cancer, the sudden realization that your pet might have a tumor is understandably distressing. Knowing what to look for can help you spot potentially dangerous situations and may even save your pet’s life.

First, a little reassurance: skin growths and lumps that develop below the skin surface are a fairly common occurrence, especially in middle-aged and senior dogs. Many are completely harmless — a cosmetic issue, at worst.

As pets age, changes occur in the skin that can cause an overgrowth of skin cells — commonly referred to as skin tags. Some dogs, especially smaller breeds such as poodles and spaniels, are also prone to plugged-up oil glands or hair follicles. These cyst-like growths may be unsightly, but they’re not problematic unless they break open and become irritated or bleed.

Larger breeds, particularly retrievers, are prone to fatty tumors beneath the skin or within muscle tissue. These fat deposits, called lipomas, are soft and can rapidly grow quite large. Lipomas can cause discomfort if they interfere with the animal’s movement, or if their size causes the overlying skin to stretch. In very rare instances, fatty tumors can prove malignant, behaving like more aggressive types of cancerous growths.

So when should you become concerned?

First, beware of growths that look like wounds but don’t heal. This is particularly true for cats. Tumors of the ears, nose and face may begin as reddened, scabbed areas rather than lumps.

Just like people, pets can suffer from melanomas: malignant growths of skin pigment cells. (White-faced animals, like fair-skinned people, are particularly prone to these skin tumors.) Melanomas tend to dark or black in colour, but may also be pale or pink. When these tumors occur in or around the mouth or feet, they can be extremely aggressive, and may spread to the lungs or bone. If you find a mass fitting this description, an immediate trip to the vet is called for.

A mast cell tumor is another common type of cancer — one that can be particularly deceiving. Mast cell tumors generally occur on or under the skin. They tend to be small and grow slowly, sometimes over a period of months or even longer. They look unimpressive, so many owners simply don’t realize how dangerous they can be. These tumors release histamine — the same chemical that the body produces in response to an insect bite or sting — so you may notice your pet scratching or chewing at the area. The lump may also be red, and may vary in size — becoming smaller over time, then growing larger. Again, schedule a visit with your veterinarian as soon as possible. Left untreated, these tumors can become extremely aggressive, potentially spreading to internal organs.

Female dogs and cats that have not been spayed, or that have been spayed later in life, stand a higher risk of developing breast cancer. These tumors occur on the belly, often starting out as firm growths under the skin that feel like tiny pebbles. They can multiply rapidly, and may spread to the lungs or lymph nodes.

Cats are less likely than dogs to develop abnormal growths — but those tumors that do occur are more likely to be cancerous. Some of the most aggressive types of tumors are deceptively innocent in appearance, so a good rule of thumb is to have any growth on your cat checked out as soon as possible. Don’t wait to see if the mass grows. Early diagnosis and treatment can be critical to preventing the advancement of the disease.

If you’ve found an unusual growth, make a point of marking the location prior to the examination. You’d be surprised how often a readily noticeable lump will seem to move or disappear once you’re in the vet’s office — especially if you happen to have a large or long-haired animal. Clip the hair short in the vicinity of the lump, or use a permanent marker on a light-coloured pet. Lipstick also works well and is easy to remove.

For a definitive diagnosis of any abnormal growth, you must arrange a veterinary exam. But your sharp eyes and vigilance are also key to ensuring early diagnosis and successful treatment.

Dr. Pamela Barker is a professional veterinarian with more than 15 years of experience, currently practicing in 100 Mile House, B.C. Her special areas of interest include animal behaviour and training, nutrition and condition for canine athletes, and public education about animal health and care. If you’d like to suggest a topic for one of her future blog posts, please feel free to leave a comment below.

Posted by Dr. Pamela Barker

Our recent online survey has shown that an overwhelming majority of you are opposed to the keeping of wild animals as pets. As a veterinarian and a former zookeeper, I wholeheartedly agree. Regardless of where they live, there are immense differences between a “tame” or captive animal and a truly domesticated one.

Domestication is a long, gradual process that involves far more than the “taming” and keeping of individual animals. In the case of the dog, this evolution has been going on for about 10,000 years. We know from DNA evidence that dogs descended from wolves, but newer theories have changed dramatically our understanding of how this likely happened.

We used to think that early humans must have raised orphaned wolf cubs, and that the descendants of those animals evolved into our domestic dogs. The problem with this theory is that it doesn’t explain why, even after generations of being raised in captivity, wild wolves don’t become domestic wolves. It also ignores the fact that, in primitive societies, food was a scarce and guarded resource. The idea that early humans would have voluntarily added another mouth to feed seems highly improbable. Wild wolves almost certainly represented danger and competition for food, not working companions. Moreover, we know that generations of other wild species raised in the company of humans, such as large cats or primates, do not become domesticated.

Turns out that the ancestors of our modern dogs likely played an active role in the domestication process. It is now believed that some wolves, as a result of naturally occurring genetic variations, were less wary of humans than were their relatives. These wolves probably approached the hunting and living areas of humans more readily, taking advantage of discarded or unattended food sources. More food meant an advantage in the struggle for survival, and a better chance to breed and produce surviving offspring.

Insightful humans may also have seen the advantage of following wolves to find prey. And they may have realized that the protective company of a predator made them less likely to become dinner for other animals.

This helps to explain the significant differences we see today between wolves and dogs. While wolves are predators, feral or semi-wild dogs tend to be scavengers. In a wolf pack, breeding is restricted to only the alpha pair, while dogs breed indiscriminately. And social structure within a dog pack (or a dog and human pack) tends to be flexible. Changes in pack order, or the social position of pack members, occurs readily and usually with little conflict. Changes of status within a wolf pack, by contrast, most often require the death or removal of a pack member.

The special qualities of dogs that make them uniquely suited for life with humans actually represent a genetic retention of juvenile characteristics. That is to say, a pet dog more closely resembles a wolf cub than a “tame” wolf. Interestingly, these behavioural traits are also linked to a number of physical traits that we see in adult domestic dogs but not wild canines: floppy ears, blunt faces, curly tails, and large white patches or a piebald (spotted) pattern. An experiment in Siberia on silver foxes, spanning the greater part of fifty years, clearly illustrated this phenomenon. Researchers seeking to breed tame foxes that were easier to handle succeeded in doing so within a few generations; in the process, however, they also changed significantly the foxes’ physical appearance and biochemical physiology.

When people attempt to keep wild animals as pets, the dramatic impact of that centuries of domestication have had become clear. While things may go fairly smoothly when the animal is young, things often fall apart once the normal changes that accompany sexual maturity begin to manifest themselves. Previously gentle youngsters begin to exhibit typical adult behaviours. In captivity they become aggressive, unpredictable and, in the case of carnivores, highly predatory.

Wild animals will behave this way, regardless of their upbringing, because they are genetically programmed to do so. Domestic animals are a result of genetic changes: selective breeding for not only physical traits, but for the behavioural traits that make them compatible for life with humans.

Each day, millions of us interact with our pets happily and safely. They live in our cities and farms, and share our homes. They ride in our cars, play with our children, and bring comfort to the elderly, ill and infirm. We trust them to carry us safely on their backs, to lead the visually impaired, and to give lifesaving assistance to law enforcement and military personnel. We don’t often stop to think how amazing it is that such different creatures have come together for their mutual benefit.

Dr. Pamela Barker is a professional veterinarian with more than 15 years of experience, currently practicing in 100 Mile House, B.C. Her special areas of interest include animal behaviour and training, nutrition and condition for canine athletes, and public education about animal health and care. If you’d like to suggest a topic for one of her future blog posts, please feel free to leave a comment below.