Focus is the Hunter Pet version of a Rogue's Energy. Focus is required for the execution of all of a pet's active abilities. By default the focus bar is full, with 100 points. When used, it regenerates fairly slowly (24.5 focus every 4 seconds). The regeneration rate is not affected by being in combat.
The size of the focus pool and the regeneration rate are both constant - they do not increase with levels, and are not related to any statistics. As of patch 2.0, the 2 point 
[Bestial Discipline] talent will increase the focus regeneration rate by 100% (prior to patch 2.0 it increased it by 10-20%).
Go to Pet (Hunter)
Go to Glossary