Meet the Huge “Sea Elephant” Heteropod in Palau’s Ocean

While diving on an Unnamed Seamount approximately 30 nm north of Tobi Island within the Palau National Marine Sanctuary, our Corps of Exploration came across something truly unique: a giant heteropod (aka Pterotracheoidea). This predatory gastropod has blue eyes and a “snout” like proboscis that allows it to suck up snails- giving it the nickname “sea elephant.” Can you spot its tiny shell on the bottom and the modified foot (visible as a dark-edged undulating fin) it uses to move? 

At more than 30 cm long (~11.5 inches) this animal is massive compared to it's coin-sized marine snail cousins. A totally pelagic creature, heteropods have evolved a transparent body lined with special organs (statotcysts) to help understand it's orientation in a world with no reference light above or seabed below. As a surprise to our team, this individual seems to be swimming upside down as it drifted in from it's open ocean home to the top of this seamount at around 700 m (2,300 ft) deep. This sighting feels like a trip back in time to a time of ancient ocean animals. 

The NA168 Lebuu’s Voyage expedition to explore the deep sea inside and around the Palau National Marine Sanctuary was conducted in partnership with the Palau International Coral Reef Center and funded by NOAA Ocean Exploration via the Ocean Exploration Cooperative Institute. It was named Lebuu’s Voyage by Palauan stakeholders as part of a strategic effort to advance traditional knowledge and best practices in tandem with scientific understanding.