I think the closest land analogue to orcas is probably wolves, since they also live in packs, which I assume means older/weaker wolves/orcas use their social connections to other pack members to get food. This, I would expect, makes these two sorts of predators less likely to attack humans out of individual desperation. However, although it's rare, groups of wolves attacking humans as prey is not unheard of. Children are particularly at risk from what I understand, since the wolves know they're weaker. (To an orca, I think any human in the water would be weak.)
