Sea Pen
About the Sea Pen
Named for their resemblance to old-fashioned quill pens. Each sea pen is a colony of specialized polyps - some form the stalk, others feed, and others pump water. They can burrow into soft sediment by inflating their base. When threatened, they can inflate to twice their size or withdraw completely into the sediment. Some species are bioluminescent, glowing green when disturbed. Over 300 species exist. They are found from 10 to 6,000 meters depth. They are among the oldest colonial animals, with fossils dating back 540 million years. Some live 100+ years.
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