Dolphin Facts

Clever facts about dolphins — the ocean's most intelligent and socially complex residents.

Dolphins are among the most cognitively complex non-human animals studied by science. Bottlenose dolphins (Tursiops truncatus) have the highest brain-to-body mass ratio of any non-human mammal after great apes, and they have passed the mirror self-recognition test — one of the most stringent markers of self-awareness used in animal cognition research. Dolphins produce individually distinctive signature whistles that function analogously to names: other dolphins in the group use these calls to address specific individuals, and dolphins retain the ability to recognise the signature whistles of companions they have not encountered for over 20 years.

Dolphin echolocation — biosonar — operates in the ultrasonic range above 100 kHz, far above human hearing. The clicks are produced in the nasal passages and focused by the melon, a fatty organ in the forehead. Returning echoes are received primarily through the lower jaw, which conducts sound directly to the inner ear. The resolution of dolphin sonar is fine enough to detect a golf ball-sized object at 100 metres.