Some busy humans are constantly aware of time passing, while animals may not even be conscious that time even exists :
Dog owners, who have noticed that their four-legged friend seem equally delighted to see them after five minutes away as five hours, may wonder if animals can tell when time passes. Newly published research from The University of Western Ontario may bring us closer to answering that very question.Full Story Is Here
William Roberts and his colleagues in Western's Psychology Department found that rats are able to keep track of how much time has passed since they discovered a piece of cheese, be it a little or a lot, but they don't actually form memories of when the discovery occurred. That is, the rats can't place the memories in time.
These results, the researchers say, suggest that episodic-like memory in rats is qualitatively different from human episodic memory, which involves retention of the point in past time when an event occurred.
"This research," said Roberts, "supports the theory I introduced that animals are stuck in time, with no sense of time extending into the past or future."
Maybe we only know what time is, and are aware of its passage, because we gave the concept of time a name, and invented clocks and watches.