Dogs, we usually understand, mostly because they are so easy to understand. They have expressive faces and body language that we can read pretty accurately. Cats, on the other hand, are known for their emotional vagueness and standoffishness.
There is a growing belief that cats are as expressive as dogs. It’s just that we misunderstand or don’t see what they’re trying to communicate.
For the increasing number of pet owners who want to connect with their often-aloof cats, experts say there’s something to gain from those attempts at communication. Cats are very independent, and so they are easily misunderstood.
Why Cats Show Their Butt
Visual communication by cats is performed via body language. The position of a cat’s ears, head, tail, and butt all convey a message to other cats and to owners as well.
Tail sniffing behavior is normal between cats, and cat butt presentation is a part of this cat talk. It's often surprising when Fluffy leaps onto your lap for a petting session, turns around and presents his (ahem) furry nether regions.
Think of this from your cat's perspective. When greeting each other for the first time (after the hissing stops!), cats sniff each other's face and neck as a sort of "Hello there." This could be compared to you nodding a greeting to a stranger at the first meeting. Cats produce cheek pheromones that signal friendship, so sniffing this area can help calm feelings of aggression or fear.
Once they feel comfortable with each other, the cat's progress to sniffing flanks. That could be similar to a human's "nice to meet you" polite handshake. This is the area that holds the family scent of other cat's body rubs, grooming, or a human's petting hand, so it tells the sniffer quite a lot about the cat.
Cat Butt Presentation
The last step is a sniff of the anal region beneath the raised tail. The cat's signature scent is found here. Kitties that keep the tail down and don't want to be sniffed might be compared to a shy person hiding her face.
A raised tail signals "I mean no threat." So, the combination of a raising a tail with offering a butt-sniffing opportunity is the equivalent of a human's enthusiastic hug or a kiss on each cheek in greeting.
When kitty presents his tail in your face, does he really expect you to sniff? Probably not. Cats are smart, and as much as they love us, they realize we are not feline. The body language of politely opening themselves up to a sniff—figuratively uncovering their face so we see and recognize the "real kitty"—is a huge compliment granted between trusting friends. The cat butt sniff offer is a back-handed feline compliment.