Hawaiian bobtail squid
Euprymna scolopes
- Not on exhibit
- Animal type
- Octopus & kin
- Ecosystem
- Coastal waters
- Relatives
- Other squid, octopuses, cuttlefishes, and the chambered nautilus; Phylum: Mollusca; Class: Cephalopoda; Family: Sepiolidae
- Diet
- Crustaceans
- Range
- Pacific Ocean; shallow coastal waters off Hawaii
- Size
- Up to 1.4 inches (3.5 cm) in mantle length
Meet the Hawaiian bobtail squid
Native to the Pacific Ocean, this species can be found in shallow coastal waters off Hawaii. It buries itself in sand or muddy areas near sea grass beds during the day—even gluing sand grains to its body to form camouflage—and emerges at night to feed.
Natural history
This pear-shaped squid has an “invisibility cloak,” thanks to a symbiotic relationship with bioluminescent bacteria that live in its mantle in a special light organ.
When the squid leaves the safety of the seafloor to hunt at night, the bacteria hide the squid’s silhouette by matching the amount of light hitting the top of its mantle—making it virtually invisible in moonlit waters when viewed from below. In return, the small squid provides the bacteria with food (a sugar and amino acid solution).
The Hawaiian bobtail squid hatchling isn’t born with this bacteria; it secretes a mucus around its light organs to capture it. Less than a day after hatching, a juvenile is able to “disappear” from predators just like its elders.
Predators
The Hawaiian monk seal is a common predator of the Hawaiian bobtail squid.
Lifespan and reproduction
This squid lives for only three to 10 months, but grows quickly. It’s able to reproduce just two months after hatching and breeds only once. The female lays eggs on the underside of coral ledges in shallows and dies shortly thereafter.
Relatives
The Hawaiian bobtail squid is a cephalopod—related to other squid, octopuses, cuttlefishes and the chambered nautilus.
Conservation
The population size of the Hawaiian bobtail squid is currently unknown, as are threats to this species.
Human impact on the ocean is growing, but so is the knowledge that we all depend on a healthy global ocean. Working together, people can discover solutions to pollution, overfishing and other common threats to coastal marine habitats.
Cool facts
- Each morning a squid vents 90 percent of its bioluminescent bacteria back into the seawater. The bacteria replenish during the day when the squid is buried in the sand. By evening, when it’s time to feed, the squid has a new crop of bacteria in its light organ that will help it evade predators.
- Materials science experts in the U.S. Air Force have studied the symbiotic relationship between the squid and its bacteria to see if the reflective qualities could be used to improve their aircraft camouflage.
Up next in coastal waters
Animal
Skeleton shrimp
Look closely to see these tiny skeleton shrimp clinging to bryozoans, hydroids or algae.
Keep exploring
Animal
Sea otter
Beyond their cute faces and fluffy fur, sea otters play an irreplaceable role in their coastal habitats.