The sheer size of a fully grown humpback whale dissuades all but the most aggressive sea predators from attacking them. In addition, whales typically swim in large groups called "pods" to protect smaller, weaker whales and youth. Mothers with calves swimming within a pod are accompanied by "escort" whales, which follow along slightly outside the pod to protect against aggression from competing humpback groups.
Escort whales scare off potential threats by blowing screens of bubbles through their blow holes. Large pods may attempt to protect themselves by wildly thrashing, swinging their tails against the water, and slapping the surface of the water with their tails. They express this behavior toward other whale pods and even toward groups of boats if they get too close.
The predators of the humpback whale include humans, large sharks and orcas. Scientists theorize that one reason humpbacks breed off the coast of Hawaii is to avoid predation from orcas, which favor cooler waters. Sharks such as the great white prey upon these breeding groups as they migrate, trailing behind and picking off the slowest whales. In cases of shark predation, the predator's strategy is for the whale to bleed out and attract more sharks to the scene. The size and strength of the whale is too much for a single shark to take down in a fight.