A Conscious Perception of Time:
This may be unique. I'm not sure any other animal demonstrates this by any implication of their behavior.
How could this perception manifest itself in behavior. How do we manifest this perception, other than by language and communication.
Are there any animals which have behaviors which seem to indicate an anticipation of their own mortality?
A sense of Morality:
(Morality: 1. The quality of being in accord with standards of right or good conduct.
2. A system of ideas of right and wrong conduct)
Morality breaks down to the judgement and perception of good and bad. The ability to pass judgement on the perceptions of good and bad, may be uniquely human.
However, if an animals behavior seemed to display guilt over an action, then we might suspect that they were applying a judgement of right/wrong to their actions, and therefor had some sense of morality. I think I've seen guilt in animal behavior before (pets I've had in the past)
A sense of Humor:
Animals definitely enjoy play, but I'm not sure it's the same thing as humor. Also, humor at another's expense may be just another form of dominance behavior, so maybe a better measure of things would be shared humor.
All a matter of degree:
It's certainly possible that there's nothing completely unique about us, and that we (and everything else) are only different to degree. But that was why I asked the question; to explore if there is something *completely* unique about us.
How about written language? No other animal seems to have that. Do any animals make marks to communicate? Claw marks on trees? Bower Birds decorate their nests, but I'm not sure that could be construed as written language.
Thanks for the answers so far
Interesting stuff.
Best Regards,