The photo of Coco in today’s comic was taken by Elaine, who has an awesome photo page called Elaine Remains. Coco passed away last Saturday.
Every dog carries an ID in his back pocket, so to speak. On each side of the rectum is an anal sac, which contains a strong-smelling fluid. This fluid is the equivalent of a dog’s thumb-print. With a quick sniff, dogs can tell more about each other than we could determine by rifling through one another’s wallets. Dogs can tell the sex, age, health, reproductive status, diet, and mood from those smells. They get all the information they need to decide whether they want to associate with that dog and what kind of relationship they ought to have.
Quotation from Dog Behavior: When Dogs Lick & Sniff “Private” Places (BestBetPetSupplies.com)