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Article: When nature calls
- Article from:
- Natural History
- Article date:
- March 1, 1996
- Author:
CopyrightCopyright American Museum of Natural History Mar 1996. Provided by ProQuest LLC. (Hide copyright information)
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Our own anatomy is often a poor guide to the behavior of other animals, particularly those in other phyla. Clinging to an intertidal outcrop of basalt in the Galapagos, this Sally Lightfoot crab (Graspus grapsus) appears to be squirting two jets of water from its mouth. But those conversant with crustacean body plans know that the animal is merely relieving itself.
According to Tom and Donna Wolcott, professors of marine science at North Carolina State University in Raleigh, the crab is equipped with two antennal glands--equivalent to our kidneys and bladder--so named because their duct openings are adjacent to the animal's antennae. These glands allow the crab to adjust its fluid volume ...