My horse keep moving to it's pack

Okay i found some horse's when i first started a game and than i tamed one (it took me until night time lol) and then i rode to find a great place for my house and barn for my horse i got off of the horse and than it keep moving to the direction where i found him/her and the direction where he/she was going had a ravines in front of it and he/she fell in the ravines and he/she died.