Beast Lore is a level 5 hunter ability that allows the hunter to see a variety of extra information about a target beast, such as whether it can be tamed. After Beast Lore is cast on a beast, the information will temporarily appear in the creature's tooltip.
Some beasts have no extra information to view. For example, casting Beast Lore on a Cow will only add "Cannot be Tamed" to its tooltip.
Beast Lore does not require the target to be a mob. It can be used on friendly targets, hunter pets, and even on players in a beast form such as [Cat Form] or [Ghost Wolf] form.
Previously, this ability could be used to find out how difficult a beast (or player, as noted above) was to fight, since it showed the target's exact armor, damage range, and HP amount.
Patch changes
Patch 8.1.0 (2018-12-11): Beast Lore now shows spec and abilities. No longer shows damage range or HP.
Previously: Gathers information about the target beast, displaying damage, health, armor, diet, abilities, whether or not the creature is tameable, and if it is exotic.
Patch 7.1.0 (2016-10-25): Now learned at level 13 (was 12).
Patch 4.0.1 (2010-10-12): Now trained at all hunter trainers at level 10.
Patch 1.6.0 (2005-07-12): Will no longer flag you for PvP or cause guard retaliation when used on an enemy faction target.
Patch 1.2.0 (2004-12-18): Beasts under the effect of Beast Lore will now display whether they are tameable or not.
[Cat Form] or 
[Ghost Wolf] form.
Patch 8.1.0 (2018-12-11): Beast Lore now shows spec and abilities. No longer shows damage range or HP.
Patch 7.1.0 (2016-10-25): Now learned at level 13 (was 12). 
Patch 4.0.1 (2010-10-12): Now trained at all hunter trainers at level 10. 
Patch 1.6.0 (2005-07-12): Will no longer flag you for PvP or cause guard retaliation when used on an enemy faction target. 
