Deep-Sea Squid Disguises as Sponge in Rare Pacific Observation

Researchers have documented a striking behavior in a deep-sea squid that camouflaged itself as sponge stalks in the Pacific Ocean. This observation occurred in the Clarion-Clipperton Zone (CCZ) and was published in the journal Ecology in December 2025. The findings highlight the complexities of cephalopod behavior and raise questions about their distribution and abundance in deep-sea environments.

The study was initiated in March 2023 during visual surveys conducted at a depth of approximately 4,100 meters using a remotely operated vehicle (ROV). Initially, the research team believed they were examining biogenic stalks, which are living structures found in deep-sea ecosystems. However, four seconds into the footage, a squid swiftly swam across the camera’s view, prompting further investigation.

Upon a closer examination of the video, the researchers discovered that the squid had been hidden beneath mud and polymetallic nodules, only surfacing just before being recorded. The squid was noted for its distinctive features: a mantle length of around 10 centimeters and long, white tentacles measuring approximately 22 centimeters. The team suspects it may be a previously unclassified species of whiplash squid within the family Mastigoteuthidae.

According to the study authors, this behavior, referred to as “masquerading,” allows the squid to conceal itself from predators, such as beaked whales, or to ambush prey. This observation marks the first recorded instance of masquerading in a deep-sea cephalopod. Prior to this, whiplash squids had been encountered only once in the Northeast Pacific abyss, with just four cephalopod sightings since seabed surveys began in the 1970s.

The researchers posit that the scarcity of sightings does not necessarily indicate low populations. Instead, it suggests that these creatures may be adept at avoiding detection. The authors of the study commented, “As with the number of genetic species, the occurrences and distributions we report here are most certainly an underestimate, since cephalopods can self-disguise as well as sense and potentially avoid underwater sampling vehicles.”

As these deep-sea areas face increasing threats from climate change and seabed mining, gaining a better understanding of their ecosystems is crucial. The abyssal plains span more than half of the Earth’s surface, yet much remains unknown about the habitats found there. Enhanced research methods with less intrusive camera platforms are essential for uncovering the diversity and behaviors of deep-sea cephalopods before these environments undergo irreversible changes.

The research team emphasizes the importance of this study in informing conservation and management strategies, particularly in regions targeted for resource extraction. By shedding light on the elusive lives of deep-sea cephalods, the findings contribute to a broader understanding of the ecological dynamics at play in one of the most obscure environments on the planet.

This article was authored by Krystal Kasal, edited by Gaby Clark, and reviewed by Robert Egan. It serves as a reminder of the complexities of marine life and the urgent need for continued exploration and conservation efforts in our oceans.