Social marine mammals that navigate with sound
Dolphin
Dolphins are toothed marine mammals known for streamlined bodies, social groups, complex communication, and echolocation that helps them hunt and move through the ocean.
What a dolphin is
A dolphin is a toothed cetacean adapted for life in water. Dolphins have streamlined bodies, flippers, tail flukes, a blowhole for breathing, and a layer of blubber that helps with energy storage and insulation. They are mammals, so they nurse their young and breathe air.
Dolphins, porpoises, and whales
The word dolphin covers many species, including oceanic dolphins and several river dolphins. Porpoises are related but usually have different tooth shape, body form, and behavior. Some animals with whale in their name, such as killer whales, are members of the dolphin family.
Bodies built for swimming
Dolphins swim by moving their tail flukes up and down, while flippers help steer. Their smooth body shape reduces drag, and their breathing is coordinated with surfacing. Unlike fish, dolphins do not use gills, and their tails move vertically rather than side to side.
Echolocation
Echolocation is a biological sonar system. A dolphin produces clicks, then listens for echoes returning from fish, objects, or the seafloor. The timing and quality of the echoes can reveal distance, shape, movement, and texture. Echolocation is especially useful where light is limited or water is cloudy.
Communication and social life
Dolphins live in social groups that vary by species, habitat, age, sex, and food availability. They use whistles, clicks, burst pulses, touch, body posture, leaps, and coordinated movement. Some species show long-term associations, cooperative hunting, play, and learning from others.
Feeding and hunting
Dolphins eat fish, squid, crustaceans, and other marine animals depending on species and habitat. Some hunt alone, while others herd fish together, use mud rings, chase prey toward shore, or coordinate dives. Hunting strategies can be local traditions learned within groups.
Human impacts
Dolphins face risks from fishing gear entanglement, ship strikes, underwater noise, pollution, habitat loss, prey changes, and climate shifts. Conservation work includes monitoring populations, reducing bycatch, protecting habitat, regulating vessel behavior, and studying sound in the ocean.
Why it matters
Dolphins matter because they connect ocean biology, animal intelligence, conservation, and human responsibility. Their lives show how sound shapes underwater worlds. Protecting dolphins also means paying attention to fisheries, water quality, coastal development, and the health of marine ecosystems.