NUDI GILL PIN-UP: Aplysia californica

In preparation for NUDI GILL, my debut picture book release in September 2022, I will be blogging about nudibranchs monthly. I’m going to diverge a bit this month to talk about sea hares, which are sea slugs, but are not nudibranchs. My hope is that you will fall in love with these little critters, too. Without further ado, allow me to introduce you to January’s fascinating supermodel:

Aplysia Californica

Sea Hare in Monterey Bay National Marine Sanctuary. Photo: Chad King/NOAA

Like nudibranchs, sea hares have rhinophores, are soft-bodied invertebrates, are hermaphroditic and do not wear exterior shells. You may be asking… “It walks like a nudibranch, reproduces like a nudibranch, is cute and squishy like a nudibranch. So what’s the difference? Well, I can name three.

  1. A sea hare has curled rhinophores like bunny ears. That’s where they get their cute name.

Photo credit: Scott F Cummins, Dirk Erpenbeck, Zhihua Zou, Charles Claudianos, Leonid L Moroz, Gregg T Nagle & Bernard M Degnan. 2009. Candidate chemoreceptor subfamilies differentially expressed in the chemosensory organs of the mollusc AplysiaBMC Biology 2009, 7:28. doi:10.1186/1741-7007-7-28. Cropped from figure 6

2. Sea hares are vegetarians who mostly eat seaweed. Nudibranchs are carnivores!

3. A nudibranch can’t do this…

Wait for it…

Are you getting excited?

I bet






Or you might be thinking…

This sea hare is

kind of boring

compared to flashy nudibranchs.

Well, you

are in

for a shock!

Okay, here it is:

Aplysia californica emitting ink cloud. Photos by Genny Anderson.

WHOA! What is going on here?

– said you just now.

The California sea hare has the ability to express purple dye from its body like an octopus. The octopus squirts (typically black) dye to provide a smoke screen or decoy so it can escape when attacked. In the case of the California sea hare, there is no chance of a quick escape. They are slugs after all. It is believed that their dye has an unpleasant taste and that is what ultimately persuades the attacker to move on to a more savory snack. Isn’t that the coolest?

Purple is the new black, my friends!

I hope you enjoyed meeting the fantastic Aplysia Californica sea hare. Stay tuned for February’s NUDI GILL Pin-Up!


Bonnie Kelso writes and illustrates books for children and adults that encourage individualism and brave self-expression. She facilitates art workshops for her local community and beyond. Her debut picture book, NUDI GILL, will be released in September, 2022. A lover of nature and travel, she can be found wandering about outside with her family whenever a good opportunity to do so presents itself.

3 thoughts on “NUDI GILL PIN-UP: Aplysia californica

  1. Each one of your illustrations is so much fun to see what you did to keep it all so cute and attractive even though some them are in nature as well. Your interpretations are so lively. Can’t wait for the book!


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