Science Friday Don’t Let Their Name Fool You—Sea Slugs Are Awesome
Dec 8, 2025
Marine biologist Dr. Patrick Krug, a professor at Cal State LA, dives into the vibrant world of sea slugs, revealing their breathtaking diversity—some are as tiny as a quarter, while others can weigh up to 30 pounds. He explores their unique feeding strategies, the fascinating ability to regenerate by detaching heads, and their stunning colors linked to chemical defenses. Krug also discusses kleptoplasty, where some slugs use stolen chloroplasts for photosynthesis, and shares insights on their reproductive quirks and contributions to neuroscience.
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Sea Slugs Are Shell-Less Mollusks
- Sea slugs are mollusks that evolved to live without heavy shells and are relatives of snails and garden slugs.
- They have diversified into many ecological roles and rely on other organisms, usually their food, to survive.
Extreme Lifestyles From Shell Loss
- Different sea slug groups evolved extreme lifestyles, from fish parasites to free-swimming sea butterflies and photosynthetic kleptoplasts.
- These adaptations show how losing a shell led to diverse, specialized survival strategies.
Heads Can Regrow Whole Bodies
- Some sea slugs can autotomize their bodies: they pop off an old body and regenerate a new one from the head in weeks.
- Patrick Krug recounts reading the paper and recognizing he had previously collected severed slug heads.