Serious question for fellow christians about book of job, dinosaur?

job talks about behemoth.says that his tale is like a mighty cedar tree. but in the niv study bible it says this creature was a hippo? last time i looked a hippo has a little tail like fan maybe a foot long. how can the the people behind this study bible say that? cedar tree vs a little tail of a hippo. sounds like to me that the evolutionist got to some of there minds!! this is a error on there reasoning.the behemoth was a dinosaur period.