I got to thinking about this because there are two floor length mirrors in our bedroom and when the cat walks by she ignores the image of herself. As an experiment I held her up to the bathroom mirror...no response; she was more interested in examining the light fixture.
Back when she was a kitten she was sitting on my lap while I was watching Animal Planet. When a scene involving lions walking towards the camera appeared, she took an interest and ran to the TV, studied it intently, and when the lions got close she started batting at the screen. When the lions didn't respond she quickly lost interest and to this day she ignores animals when they appear on the television.
In psychology the mirror test is considered an important evaluation as a sign of the normal development of cognitive skills in children. Humans are typically 18 months old before they are able to recognize themselves in the mirror. But what about animals?
Studies have shown (yes, people actually experiment with this stuff) that only higher primates, dolphins, orcas, elephants and European magpies are known to recognize that what they see in a mirror is a reflection of themselves. Here is an odd fact...pigs show no sign of recognizing their reflections in a mirror but they are able to identify the location of food placed behind them.
Why is that? Evidently only animals that rely on vision as their primary sense are impressed with mirrors.
When a kitten or puppy first sees his image in a mirror they often react as if it is a strange animal. But, cats and dogs both check new things out by sniffing them. So the theory is that when cats or dogs see themselves in a mirror there is nothing to smell, so they aren't interested.
A controversial test was designed to see if animals could recognize themselves in mirrors. Gordon Gallup, Jr., a professor at Tulane University, showed chimpanzees their reflection. He isolated two chimps in cages and placed a mirror in each cage for eight hours at a time over 10 days and observed their behavior. At first they treated the reflection like it was another chimp, but over time they started using it to explore their own bodies. They used the mirror to look at the inside of their mouths, to make faces and to inspect their genitals and even to remove mucous from the corner of their eyes.
Gallup was not completely sure that the chimps recognized themselves in the mirror though so, under anesthesia, he painted one eyebrow ridge and the opposite ear tip with a red dye that they would not be able to feel or smell. The idea was that if they really did recognize themselves then they would inspect the new marks and that's exactly what they did.
Next he tested monkeys, which are different than chimpanzees. The monkeys did not react the same. The conclusion was that the ability to recognize one’s reflection is not a matter of learning abilities but one of higher intellectual capacity. Charles Darwin had shown mirrors to orangutans, but they didn’t respond and in 1889 a German researcher named Wilhelm Preyer claimed there was a connection between mirror self-recognition and an inner sense of self in people, but that's a whole other area.
In the early 1990s two bottlenose dolphins at an aquarium were exposed to a mirror. Like the chimpanzees, the dolphins learned to use the mirror in a variety of ways that suggested they recognized themselves. To test the theory they used a modified “mark test” by marking black ink on various parts of their bodies and the dolphins went through a lot of contortions trying to examine the marks.
What was controversial about these experiments was that one researcher became convinced that the mirror test indicated that there is at least some level of self-awareness on the part of the animals and that made it unethical to keep them in captivity. As a result she set up the Nonhuman Rights Project which is attempting to gain legal rights for animals with higher-order cognitive abilities by getting courts to recognize them as “legal persons.” Their belief is some animals are, like humans, self-aware and so can also suffer mental anguish because of their captivity. But all that is another matter.
The point is that while some animals recognize themselves in a mirror, most of the ones we are associated with, cats and dogs, don't. They may, as mentioned, treat their image as another animal the first time, but they quickly lose interest. And, as mentioned, for humans recognizing you own image in a mirror is a major mental feat because it requires self-awareness, which is one of the most sophisticated aspects of consciousness. And, we are not born with the ability to recognize ourselves in mirrors. Young infants may be fascinated by their reflection, however they view this as social interaction with what appears to be another baby. Somewhere between the age of 18 and 24 months babies begin to understand that they are looking at themselves. Interestingly, a baby recognizing itself in a mirror was tested using nearly the same “spot test” that was used on animals.
However, one researcher concluded that dogs do have some sense of self-awareness as well as a sense of what's his and what belongs to someone else...like his territory, his toys and his sleeping place, but they fail the mirror test because there is no smell. In the dog's mind (or a cat's) the reflection isn't important enough to warrant attention if it has no smell.