Blue whales are the largest predator to ever inhabit this planet, though it is thought to feed almost exclusively on tiny, shrimp-like creatures called euphausiids or krill. Feeding is usually at depths less than 100 m; harpooned animals have dived as deep as 500 m.lue whales, Balaenoptera musculus (Linnaeus, 1758), like all rorquals (Family Balaenopteridae, the family that includes the blue whale, Bryde's whale, fin whale, humpback whale, minke whale, and sei whale), are long, slender whales that are much more streamlined than other large whales.