Discover

Today
Animals
Explore
Archive
Search

Use it

Classroom
Resources
Field lab
Quiz
Saved

Trust

Methodology
Sources
Corrections
Accessibility
Contributors

Details

About
Contact
Privacy
Terms
Newsletter

Animal profile

Sea Squirt

Ciona intestinalis

AscidiaceaHarbours, pilings and hard substrates in temperate coastal waters

Field profile

A translucent, sac-like tunicate that attaches to hard surfaces and filters water through two siphons. Adults are sessile and superficially resemble simple invertebrates. Their larvae reveal that tunicates are the closest living relatives of vertebrates.

Scope note

This is an editorial profile, not a diagnostic field-identification guide or a substitute for current conservation assessments. Follow the cited sources on each fact for the evidence trail.

Published field notes

2026-09-02

Sea Squirt

The sea squirt larva is built like a tadpole

The adult is a filtering sac with no backbone and no obvious head. Its larva, by contrast, swims with a tail stiffened by a notochord and a dorsal nerve cord, the defining features of the group that includes vertebrates.

Read with evidence →

Sea Squirt | Daily Animal Facts