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The ampullae of Lorenzini are a group of organs on the heads of sharks. It is composed of tiny holes, usually concentrated in the snout, which connect to jelly-filled canals. These in turn connect to the ampullae (singular ampulla), which are themselves connected to the nervous system. The ampullae of Lorenzini detect the electromagnetic impulses created by all living things. They are of little use in long-range hunting, in which the olfactory dominates1, but they are extremely useful within their range of a few inches. They are typically pronounced and vital in sharks deriving a substantial portion of their diet from shellfish and other bottom-dwellers2, because of their efficacy in detecting buried prey.

1: Some sharks can detect a single part of blood in one million parts of water.

2: Sharks such as these are also characterized by their broad, flat teeth, useful in crushing exoskeletons. Examples include the tiger shark and the nurse shark.

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