No, nothing humans do is any different from what animals do save that our evolution moved into a more rapid cultural/social form leading to an exponential advancement of sophisticated adaptation. There is no behavior in humans that is "special" or hasn't been observed in some primitive progressive form in other animals.
"Sentience" is a very mushy term. We make arbitrary distinctions as to where various lines are (self-awareness, empathy responses, self-recognization, tool use, problem solving, etc...), but they are just that: arbitrary. There is nothing fundamentally different between humans and any other animal save our accelerating rate of adaptation brought on by the exponential growth of "culture" and the transmission of memes through symbolic language.
I was going to say racism but after doing a search it looks like that is actually seen in animals. I was expecting dogs to be the example actually but apparently horses were what they went with. I was also going to go with sexual fetishes but that was easily shown to exist in nature after a search as well. I think the only one I have been unable to find anything on would be religion among animals. I am more curious as to whether that exists and where than being right as I think that would be interesting to read about.
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Wow didn't expect Breitbart to die suddenly...
http://www.washingtonpost.com/local/obituaries/comic-actor-steve-bridges-who-impersonated-george-w-bush-dies-in-los-angeles/2012/03/05/gIQAipI3sR_story.html