Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
Birkenia
Introduction References & Edit History Related Topics
Quizzes
Sea otter (Enhydra lutris), also called great sea otter, rare, completely marine otter of the northern Pacific, usually found in kelp beds. Floats on back. Looks like sea otter laughing. saltwater otters
Animal Group Names
Lion (panthera leo)
Deadliest Animals Quiz
Young chimpanzee dressed in a shirt and sweater vest, scratching his head thinking. (primates)
Wild Words from the Animal Kingdom Vocabulary Quiz
Mute swan with cygnet. (birds)
Match the Baby Animal to Its Mama Quiz
The bearded vulture (Gypaetus barbatus) is seen in Switzerland on December 2024
Animal Factoids
Quick Facts
Britannica AI Icon
Adding us as a Preferred Source tells Google you trust our content, so our articles show up more often in your Google Search, Discover feed, and AI Overviews.
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

External Websites

Birkenia

fossil vertebrate genus
Written and fact-checked by
Britannica Editors
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....
Britannica Editors
History

Birkenia, genus of extinct early fishlike vertebrates found in Late Silurian and Early Devonian rocks in Europe (from about 421 to 387 million years ago). Birkenia was a primitive jawless vertebrate that attained a length of only about 10 cm (4 inches). Birkenia was adapted for active swimming, and its sucking mouth was in a terminal rather than a ventral position. The head of Birkenia was covered by small scales rather than by the fused bony shield of some of its relatives.