The Dolphin Family

The Dolphin Brain

How Echolocation Works

Dolphin Behaviors

Cerebral Matters

Both humans and dolphins have invested a lot in evolving a big brain, though sometimes to different ends. Dolphins don't process high-level information in enlarged frontal lobes as we do, but they're adept at solving problems and can apparently plan for the future.

Seeing With Sound

Dolphins have evolved a sensory system to detect objects underwater using the echoes created by sounds. Sound travels four times as fast in the water as in the air.

How Echolocation Works

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1 Dolphins produce clicks by pushing air past structures called phonic lips, which are attached to the blowhole. The sound is then beamed through fatty tissue called the melon. Changing the shape of the melon directs the beam.

2 The beam of clicks bounces off the target and returns to the echolocating dolphin. Clicks can be overheard by neighboring dolphins.

3 The lower jaw—like the melon, filled with acoustic fat—directs an incoming echo to the brain via the ear and auditory nerve.

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Dolphin Behaviors

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Using tools
In Australia some dolphins put marine basket sponges on their rostra, or beaks, to protect against abrasion while they probe the seafloor for prey.

Teaming up
Two small groups of males sometimes work together to herd a female away from her companions. If they succeed, one of the groups gets to mate with her.

Strand feeding
Some dolphins will charge toward shore, making waves that force fish onto land. The dolphins then beach themselves to feast.

Remembering each other
Dolphins can recognize the signature whistles of other dolphins, perhaps even if the animals haven’t encountered each other for as long as 20 years.

Fernando G. Baptista and Daniela Santamarina, NGM Staff; Mesa Schumacher and J. L. Wang. Internal Structure Illustrations: Shizuka Aoki. Text: Rachel Hartigan Shea. Audio: Marcelo Magnasco, Rockefeller University; Diana Reiss, Hunter College, CUNY. Sources: Sam Ridgway, National Marine Mammal Foundation; Denise Herzing, Wild Dolphin Project; Rachel Racicot, Howard University; Diana Reiss, Hunter College, CUNY; Juan Troncoso, Johns Hopkins University