Photo: wheany (flickr)
Anyone who owns a cat is familiar with the head-bumping way they greet you.
If you are standing up, the cat may make a figure eight around your feet, colliding slightly with your legs. If you are sitting down, it may rub the side of its face along some part of you, from the edge of the mouth back to the flattened ears. Occasionally it may actually bump you head-on.
Most pet owners take this appealing behavior as evidence of affection on the cat’s part, coupled perhaps with a desire to be petted. Although we allow ourselves the assumption that cats think the way humans do, it is probably to some degree accurate.
Like most behaviors in complex creatures, however, that bump-rub has more than just one function. As you may have suspected if you ever noticed the cat rubbing chairs and table-legs with the same friendly affection.
A cat’s sense of smell is much stronger than a human’s, and they use odors to mark their territory. Outdoors, these message-bearing odors may come in the form of spraying or defecating where other cats will smell it; fortunately, indoors a cat marks its territory by rubbing sweat onto things. The particular sweat glands that exist along a cat’s snout, head, and to a lesser extent along its flanks, contain pheromones, or message-carrying chemicals that we humans won’t notice.
Next time Fluffy the cat rubs up against you, she may indeed be expressing affection, but she’s probably also putting an invisible marker on you that says this belongs to Fluffy.