I stomped across this question and would very much appreciate any form of clarification. 

A otter 75kg slides down a hill starting from rest. Hyp = 8.8, height = 6.5, final speed of otter = 9.2 m/s. And it wants me to find how much energy was lost due to nonconservative forces on the hill? 

I guess my question is what the term nonconservative means in this context. I am not asking anyone to do this for me, I merely ask for some advice or even which formulas I could use to solve this. Is friction a nonconservative force? If so, do I just have to find how much work was done by friction?
Thanks in advance!