Squirrel almost encounter

On a climb today my wife yells squirrel coming up tree. I look around and see nothing. Then I hear him coming up the back side. I thought I was about to come face to face. Wife said he was a young squirrel and just sniffed the line. But do admit made me alittle nervous. Maybe I am chicken, but he has sharp teeth! Just a side note: There were no nests in that tree, just an adventurous squirrel.