page_title: Cetacea
section_title: Intelligence
hierarchical_section_title: Cetacea / Behaviour / Intelligence
caption_attribution_description: Cropped version of the single breaching orca picture from Hood Canal. May 2005.
context_page_description: Cetaceans are aquatic mammals constituting the infraorder Cetacea. There are around 89 living species, which are divided into two parvorders. The first is the Odontoceti, the toothed whales, which consist of around 70 species, including the dolphin, porpoise, beluga whale, narwhal, sperm whale, and beaked whale. The second is the Mysticeti, the baleen whales, which have a filter-feeder system, and consist of fifteen species divided into three families, and include the blue whale, right whale, bowhead whale, rorqual, and gray whale.
  The ancient and extinct ancestors of modern whales lived 53 to 45 million years ago. They diverged from even-toed ungulates; their closest living relatives are hippopotamuses and others such as cows and pigs. They were semiaquatic and evolved in the shallow waters that separated India from Asia. Around 30 species adapted to a fully oceanic life. Baleen whales split from toothed whales around 34 million years ago.
  The smallest cetacean is Maui's dolphin, at 1 m and 50 kg; the largest is the blue whale, at 29.9 m and 173 t.
context_section_description: Cetacea are known to teach, learn, cooperate, scheme and grieve.
  Smaller cetaceans, such as dolphins and porpoises, engage in complex play behavior, including such things as producing stable underwater toroidal air-core vortex rings or "bubble rings". The two main methods of bubble ring production are rapid puffing of air into the water and allowing it to rise to the surface, forming a ring, or swimming repeatedly in a circle and then stopping to inject air into the helical vortex currents thus formed. They also appear to enjoy biting the vortex rings, so that they burst into many separate bubbles and then rise quickly to the surface. Whales produce bubble nets to aid in herding prey.
  Larger whales are also thought to engage in play. The southern right whale elevates its tail fluke above the water, remaining in the same position for a considerable time. This is known as "sailing". It appears to be a form of play and is most commonly seen off the coast of Argentina and South Africa. Humpback whales also display this behaviour.
  Self-awareness appears to be a sign of abstract thinking. Self-awareness, although not well-defined, is believed to be a precursor to more advanced processes such as metacognitive reasoning (thinking about thinking) that humans exploit. Cetaceans appear to possess self-awareness. The most widely used test for self-awareness in animals is the mirror test, in which a temporary dye is placed on an animal's body and the animal is then presented with a mirror. Researchers then explore whether the animal shows signs of self-recognition.
  Critics claim that the results of these tests are susceptible to the Clever Hans effect. This test is much less definitive than when used for primates. Primates can touch the mark or the mirror, while cetaceans cannot, making their alleged self-recognition behavior less certain. Skeptics argue that behaviors said to identify self-awareness resemble existing social behaviors, so researchers could be misinterpreting self-awareness for social responses. Advocates counter that the behaviors are different from normal responses to another individual. Cetaceans show less definitive behavior of self-awareness, because they have no pointing ability.
  In 1995, Marten and Psarakos used video to test dolphin self-awareness. They showed dolphins real-time footage of themselves, recorded footage and another dolphin. They concluded that their evidence suggested self-awareness rather than social behavior. While this particular study has not been replicated, dolphins later "passed" the mirror test.
caption: Killer whale porpoising
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