By Laura Geggel, Senior Writer | February 2, 2017 11:30am ET
This story was updated Feb. 2 at 11:30 a.m. EST.
A wild octopus surprised an Australian diver this week by suddenly, and quite dramatically, inflating itself with water, ballooning up like a parachute. Later, when the diver posted a video of the interaction online, she wondered whether the octopus was trying to intimidate her with its grandiose size.
That's possible, marine biologists said, but they can't agree on what caused the curious behavior.
One idea is that the octopus was hunting for food, said Kathleen Sullivan Sealey, an associate professor of biology at the University of Miami, who doesn't know the diver but watched the video online.
In the video post, the diver noted how the octopus "blew itself up like a parachute multiple times," turning its body and eight legs into a giant net as the animal traversed the rocky and sponge-filled ocean floor off the coast of Melbourne, Australia.