(Kongensvoll - South-Trøndelag / 19 meters / 10.12.2001)
(Kongensvoll - South-Trøndelag / 19 meters / 10.12.2001)
The Siphonophores are free-swimming or floating (pelagic) colonies. Unlike species of the two other major orders of Hydrozoans, the Athecate and Thecate hydroids, the medusae are never released from the stem. Sometimes the colony resemble a single animal, like the Portuguese Man o'War (Physalia physalis).
The colony is often held together by a long thread where different kinds of specialized animals are attached. Some digest food, while others are use stinging tentacles to catch their prey. They hand the food over to the "stomachs" that swallow and digest the food, and thus provide nutrition for the entire colony. Some even emit light.