Oh, snap! Cat owners typically spend far less on health care for their pets than dog owners do. • Dogs with cancerous growths in their mouths have the chance at an increased life expectancy after tumor removal with the help of a new therapeutic canine melanoma vaccine, Oncept. The vaccine contains a substance produced by human DNA that is similar enough to dog’s genetic material that it targets canine melanoma cells, but is different enough to be considered foreign by the dog’s immune system, resulting in a potent immune response against canine melanoma cells. Dogs with stage II or III melanoma typically survive six months or less after tumor removal, but dogs vaccinated with Oncept had a longer survival time than those not vaccinated, according to DVM360.com.

• Cats should be hissing at the news that dog owners spend an average of $219 on veterinary visits each year, while cat owners spend an annual average of $179. So says the American Pet Products Association.

• Sperm are good team players in animals who mate with several males in quick succession. Sperm will make a collaborative push with their relatives for the egg, sometimes with hundreds of sperm linking to each other in an effort to cut out the competition. The strategy has risks, as the linking can set off a chemical reaction that can leave an individual sperm infertile, but the success of one is worth the loss of some. Previously, researchers assumed sperm linked with their closest neighbors, but Harvard University found that even sperm from two brothers would not link, but would link up only when from the same male.

• People who are overweight are more likely to have overweight dogs, although fat cats don’t correlate with an increased weight of an owner, according to a study published in Public Health Nutrition. More than half of all of pets in the United States are overweight. — Dr. Marty Becker and Mikkel Becker Shannon