Blue whale massacre crustaceans
The blue whale, the worlds largest animal at 110 feet according to guiness world records eat krill, which are shrimp-like crustaceans only about an inch-and-a-half long.
Pick on somebody your own size? Not whales! An adult whale might slaughter 40 million, or 4-6 tons of these little creatures in one day!!
Amazingly, the krill population persists, but you have to assume this perpetual atrocity affects the krills ability to develop a stable society.