Several hundred individuals have been seen traveling in a single herd. These social mammals commuicate by squeaking, grunting, trilling, and moaning. They also send messages through body language by leaping, breaching , smacking their tails against the water, butting heads, and jaw-snapping. Within each pod, some dolphins are more dominant than others. Natural predators pursue dolphins.
Sharks are a dolphin's main predator.
Dolphin remains are often found in the stomachs of tiger sharks, dusky sharks and bull sharks. On occasion, killer whales may feed on some species of dolphins. Human activities can harm dolphins. In some parts of the world, humans hunt certain types of dolphins for food. Yet even where they're not hunted, dolphins are threatened by some human activities.