Pokedex EntriesSome of the following information is based off of Gogoat's "official" profile and other books from Pokemon, while the rest I have gathered from playing Pokemon. Some information may be based off of the manga version as well if stated other wise.
X VERSION: It can tell how its trainer is feeling by subtle shifts in the grip on its horns. This empathetic sense lets them run as if one being.
Y VERSION: They inhabit mountainous regions. The leader of the herd is decided by a battle of clashing horns.
In both version of the game, Gogoat can be found in the wild grasses in the Friend Safari. This Safari is located in Kiloude City. It's a facility made for trainers to catch Pokemon that they normally can't on their journeys. All of the Pokemon found in the Friend Safari are on level 30. Pokemon encountered in the Friend Safari have a 1/512 chance of being Shiny; this rate is unaffected by the Shiny Charm. There is a 25% chance that you will find a Gogoat in the grass here.
You have a 50/50 % chance of getting a boy or a girl of Gogoat, so the decision is all yours! However, Gogoat is a rare Pokemon to find, and so is Skiddo, the stage before. So, if you are just trying to catch one, I would go with the first one you find!