Hawaiian Bobtail Squid

Community Contributed

By Hannah Osland

If you are ever wandering around the reef flats along the south shore at night, you may come across a small animal in the water that looks like a baby squid or octopus. This animal might actually be a Hawaiian bobtail squid — a bobtail squid, not a he‘e — and is about the size of your thumb. They appear reddish or brownish in color, have large eyes, eight arms and two feeding tentacles. At first glance, these little bobtail squids may appear unassuming, but they have a special relationship with a glowing bacteria called, Vibrio fischeri, that live inside their bodies. The bobtail squids provide a cozy home for the bacteria, and in return, the bacteria allow the bobtail squid to produce light from their bodies. This light produced matches the amount of light coming from the moon, making the bobtail squids invisible to predators by eliminating any shadows. 

Scientists have studied the Hawaiian bobtail squid and the glowing bacteria for decades in labs on Oahu, but there’s still a lot we don’t know about their lives in the wild. 

Molokai provides a home for a population of these animals along the south shore, where they have plenty of small shrimp and crabs to eat on the shallow reef flats. I used to work as a research technician studying these animals in a lab at the University of Hawaii, but I am now a graduate student studying how these animals are different across the Hawaiian islands. Thanks to Captain Clay Ching and Jeannine Rossa, my partner and I were able to observe these animals off the south shore over the past month to learn more about what makes the Molokai Hawaiian bobtail squid different from those on Oahu. 

So, stay tuned for more updates on these amazing animals and for a potentially unique Molokai population of Hawaiian bobtail squid! For more information, comments, sightings, questions, or opportunities to get involved, please email me, Hannah Osland, at osland@hawaii.edu.