When tracking bison in Poland last week we also came across another sign of their presence. The bison had rubbed themselves against this tree-stump (see photo) and left some tell-tale hair. The colour, texture and height of the hair on the stump clearly indicates that it was bison. Rubbing against tree stumps like this is probably a kind of comfort behaviour, done to ease an itch or remove ticks. We found a small herd soon after finding this sign.