While kayaking in Pamlico Sound, or just exploring the shallow waters close to shore, you might encounter an odd-looking creature attached to a piling or other submerged object. If you pick it up and it squirts water at you, you've almost certainly discovered a sea squirt.
As Pat Garber writes in Ocracoke Wild, A Naturalist's Year on an Outer Banks Island, sea squirts appear to be "primitive, dull organism[s]." In truth, however, they "are among the most highly evolved animals in the sea."
Sea Squirts are Tunicates or Urochordates, organisms that evolved in the early Cambrian Period, beginning about 540 million years ago. I was fascinated to read that they are members of the phylum Chordata (a group that includes fish, birds, humans, and other vertebrates). It is difficult to imagine, but sea squirts, in their larval stage, are mobile and posses a primitive backbone, a spinal cord, and a primitive brain.
Pat points out that sea squirts' development curiously stops abruptly...and they "grow backwards." She says "their tails are absorbed, their body shapes alter, their stomachs and hearts migrate to the bottom, and their mouths enlarge into spout-like openings." It is during this time that they become immobile and attach themselves to stationary objects, sometimes living in clusters.
What an amazing, awe-inspiring world we live in! Look for sea squirts on your next excursion into Pamlico Sound. I believe Pat's book is out of print, but you can borrow a copy at the Ocracoke library.
Our latest Ocracoke Newsletter is the story of slavery on Ocracoke. You can read it here: http://www.villagecraftsmen.com/news092111.htm.