Extremely dependent upon estuaries, mudflats and the sheltered beaches of significant bays, approximately 135 species of shorebirds move through and inhabit North America. Alaska's Copper River Delta, Washington's Gray's Harbor, and the New Jersey and Delaware beaches of Delaware Bay are critical shorebird staging and feeding areas. Sometimes, pods join together to form temporary herds of up to several hundred individuals. Dolphins coordinate this social behavior by communicating through squeaks, grunts, trills, and moans. They also communicate via body language by leaping, breaching, smacking their tails against the water, butting heads, and jaw-snapping.
Communication helps dolphins coordinate their hunting techniques so that the whole pod catches food.
Dolphins living in the open ocean often swim in tight circles around a school of fish and take turns dashing in to catch a bite. Closer to shore, dolphins often herd fish into shallow water, keeping them trapped while other group members feed. Oceans host more varied life forms than dry land environments. Scientists classify organisms using a series of hierarchical categories called taxa. The hierarchical system moves upward into larger and larger groups of organisms.