The National Aquarium and its Animal Care and Rescue Center are temporarily closed in response to COVID-19 (Coronavirus). CLICK HERE for more information.

A Blue View: The Fierce Feeding Tactics of Nudibranchs

You might not expect a sea slug to be particularly pretty, but nudibranchs—toxic sea slugs—could take the crown in an undersea beauty pageant.

Published March 17, 2015

nudibranch

Image via WikiCommons

The brilliantly colored creatures owe it all to their food. Epitomizing the expression “You are what you eat,” nudibranchs derive their vibrant hues from their prey, which ranges from algae, sponges and anemones to barnacles, corals and even other nudibranchs. 

As you probably guessed, sea slugs aren’t the quickest predators, and their tiny eyes provide limited sight. But nudibranchs are hardly helpless. On their heads, two highly sensitive tentacles, called rhinophores, allow them to smell, taste and feel their way around. These appendages receive chemical signals helping them to identify potential prey. 

nudibranch

Image via WikiCommons

Once they’ve found their next meal, nudibranchs scrape up their food with a file-like organ on the mouth, called a radula. It’s covered with chitinous teeth that help tear apart their prey. Pretty fierce for a delicate-looking sea slug, right?

Nudibranchs aren’t afraid to be adventurous with their food either, chowing down on the poisonous anemones that most aquatic creatures avoid. The sea slugs sneak up on their poisonous prey; raise themselves above the anemone, carefully dodging tentacles; and then invert their mouths and dive into their dinner.

Once the anemone realizes what’s happening and withdraws its tentacles, it’s usually too late. The digestion process has already begun. What’s more, the sea slug is simultaneously stealing the anemone’s defense mechanism, storing the stinging tentacles underneath its own skin. Predators beware: This nudibranch is now armed and dangerous. 

To learn more about nudibranchs, listen to this week’s A Blue View podcast!

Previous Post

Featured Stories

Calypso header Remembering Calypso

We’re looking back at Calypso’s incredible life and reflecting on the many ways she impacted the lives of those who knew her best.

Read the full story

octo header No Hands? No Problem: Tool Use Among Aquatic Animals

Aquatic animals are resourceful—just like humans, when they can’t solve a problem, they can look to the world around them ... and fashion tools!  

Read the full story

Related Stories

Caring For Trafficked and Seized Animals: A Multi-Aquarium Effort!

Published September 11, 2019

A Blue View: Nudibranchs

Published April 26, 2016