You have to get up at 6:00 a.m. during the week. But you dont even have to set your alarm, because your cat comes in and licks your fingers or jumps up and purrs on your chest just before you wake up. How do cats do it? Do they really sense what hour it is, or is it something else? Alas, this is one of the many enduring mysteries about cats, says Larry Myers, DVM, PhD, of the Auburn University School of Veterinary Medicine in Alabama. “Some of what appears to be cats telling time is entrainment. Its routine reinforced. Cats very quickly become aware of when human family members wake up, eat, go out and come home,” says Dr. Myers, whose 18-year-old female cat wakes him at 6:00 a.m. daily for breakfast. In fact, it often seems more likely that our cats are training us than that they innately know what time it is. This is especially true when a cat wants to eat. “But it wouldnt surprise me if cats had some kind of internal rhythm, says Dr. Myers. “Thats true of other species [like birds]. However, there hasnt been enough research done on the issue of cats and their sense of time.” Environmental Cues. We do know, however, that there are lots of cues that cats take from their environment. Sunlight, the song of birds, the jangle of keys in the door lock – all these things let cats know whats happening in the world. Being the intelligent creatures they are, cats respond to these external cues. And when we or something else reinforces these behaviors, cats will often perform them regularly. There are also internal cues that drive cats to do things at certain times. These include hunger, thirst, the need to eliminate and the desire to play or socialize,” says Dr. Myers. Although some of these issues are greater for dogs, they can explain why your cat appears to be waiting for when you get home.