Heatran is a Legendary Pokemon which can be male or female but cannot breed. To capture Heatran you must do a side quest and have the National Dex. Go to Hard Mountain and team up with Buck who you meet in the main room. To get to
The Main room you must have 3 HM's to get through the first room. When you have reached the small room Bucky will take the item in there and leave. Go to the Resort Area on the other side of the island and talk to Buck and return to the room in Stark Mountain and battle Heatran. Use Dusk balls as they are very effective against it. Heatran is at level 70 and can learn the following moves when you have captured it. All legendaries have at least a 580 stat total.