Earlier this year, researchers at the University of Washington published a paper in the Proceedings of the National Academy of Sciences on the spotted ratfish, sometimes called a ghost shark. 

It’s one of the most common fish you’ll find in the Puget Sound and it has teeth in an unexpected place. The study’s authors say that, not only is this unusual, but it also tells us something very interesting about evolution. 

GUEST: 

Karly Cohen, post-doctoral researcher at Friday Harbor Labs

RELATED LINKS:

PNAS: Teeth outside the jaw: Evolution and development of the toothed head clasper in chimaeras

Smithsonian: This Deep-Sea Fish Has Teeth on Its Forehead—and It Uses Them for Sex 

University of Washington: This common fish has an uncommon feature: Forehead teeth, used for mating 

 

Thank you to the supporters of KUOW, you help make this show possible! If you want to help out, go to kuow.org/donate/soundsidenotes

Soundside is a production of KUOW in Seattle, a proud member of the NPR Network.

Earlier this year, researchers at the University of Washington published a paper in the Proceedings of the National Academy of Sciences on the spotted ratfish, sometimes called a ghost shark.&nbsp; It&rsquo;s one of the most common fish you&rsquo;ll find in the Puget Sound and it has teeth in an unexpected place. The study&rsquo;s authors say that, not only is this unusual, but it also tells us something very interesting about evolution.&nbsp;
GUEST:&nbsp;
Karly Cohen, post-doctoral researcher at Friday Harbor Labs
RELATED LINKS:
PNAS: <a href="https://www.pnas.org/doi/10.1073/pnas.2508054122">Teeth outside the jaw: Evolution and development of the toothed head clasper in chimaeras</a>
Smithsonian: <a href="https://www.smithsonianmag.com/smart-news/this-deep-sea-fish-has-teeth-on-its-forehead-and-it-uses-them-for-sex-180987300/">This Deep-Sea Fish Has Teeth on Its Forehead&mdash;and It Uses Them for Sex</a>&nbsp;
University of Washington: <a href="https://www.washington.edu/news/2025/09/04/common-fish-has-forehead-teeth-for-mating/">This common fish has an uncommon feature: Forehead teeth, used for mating </a>
&nbsp;
Thank you to the supporters of KUOW, you help make this show possible! If you want to help out, go to <a href="http://kuow.org/donate/soundsidenotes">kuow.org/donate/soundsidenotes</a>
Soundside&nbsp;is a production of KUOW in Seattle, a proud member of the NPR Network.

Soundside

A recent study on the spotted ratfish looked at the fish's unusual feature and what it tells us about evolution

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