Feral druid tanks have the highest health pool in the game. It absorbs damage and gives enough time for the healers to fully heal them. Next to blood death knights, they are the preferred off tanks. However, the damage that a feral druid can do is the highest of all Wotlk tanks, meanwhile Blood Dk can provide Hysteria.

Rotation for Feral Druid Tank Wotlk

Feral Druid Tank Priorities

Keep Faerie Fire on the target > Mangle > Keep 5 stacks of Lacerate on the target > Maul without rage starving > Swipe as a filler

Tips

Never leave Bear Form while tanking, not even for combat ress, that will mean certain death.

Use Survival Instincts, Barskin, Frenzied Regeneration, and Enrage (Set bonus) to mitigate damage spikes when required, and Berserk has a threat/DPS boost as much as possible.