While your pet is active, you and your pet will regenerate X% of total health every 10 sec sec.
"After the hunt, we rest here as one entity and together feel our strength return.[1]
Spirit Bond is a Beast Mastery talent for hunters. Every ten seconds, the hunter gains 1% of their max health per rank, up to two ranks. The talent is constantly active as long as the hunter's pet is alive. The healing effect also applies to the pet.
Note: Originally this healed you for a small amount when your pet hit the target, and it lasted only 30 seconds.
At higher levels with more Stamina, it begins to count almost as much as a free tic of Mend Pet.
It seems to generate some threat on your pet. (You shouldnt have taken any damage for the tic to affect you, thus removing the possibility of gaining any aggro from this buff.)
It may keep you alive, but it doesn't stop you or your pet from getting killed.
Sadly it does not provide a large portion of health returned. Many Hunters say it would be worth investing two points in if it returned more of their health. 5/6% seems to be a general consensus of what the Rank 2 of Spirit Bond should be.