Since all the other D animals have an Exchange icon that let you gain resources when you discard the card, it seems suspect that the Orca has no such icon. It also feels unthematic/illogical. Could this be a misprint?
If it is not a misprint: so in a "D" type energy/elder depletion event, you can still choose to discard the Orca as an alternative, even if this does not give you any resources? (Why would an orca, of all animals, not give you any energy?)
As I recall, this is because the orca is the only “domestic” creature in the game in which it is humans that are domesticated, rather than the other way around. The methods by which orcas train humans is mentioned in the fluff text as “the law of the tongue “.