1. Mature sea pens provide shelter for other animals, such as juvenile fish. 2. RLuc was isolated from the sea pansy " bioluminescent sea pen . 3. A bilingual guide proudly pointed out the boulder-sized adults in a sea pen . 4. When touched, sea pens emit a bright greenish light; this is known as bioluminescence. 5. Most of the strays get out when storms or seals damage their floating sea pens . 6. Their primary predators are nudibranchs and sea stars, some of which feed exclusively on sea pens . 7. Some sea pens exhibit glide reflection symmetry, which is rare among non-extinct animals ( see ). 8. While generally sessile animals, sea pens are able to relocate and re-anchor themselves if need be. 9. Keiko's emergence in the sea pen marked his return to native Icelandic waters he left at age 2. 10. Similar fossils from the Ediacaran ( ala " Charnia " ) may represent the dawn of sea pens .
