Rare Deep Sea Squid’s “Human-Like Teeth” Actually Folded Lips, Scientists Confirm

A viral image circulating on social media since 2013 shows what appears to be a small sea creature with an uncanny set of human-like teeth. The image, which resurfaced most recently in October 2025, has captured widespread attention across Facebook, Reddit, X, Threads, and TikTok for its bizarre appearance.

The creature in question is real, but there’s more to the story than first meets the eye. The seemingly human-like dental features aren’t teeth at all, according to marine biologists who have studied the specimen.

The creature is a rare deep sea squid species called Promachoteuthis sulcus, first documented scientifically in 2007. What many internet users have mistaken for teeth are actually “circular, folded lips, of which only the upper and lower portions can be seen” in the photograph, according to researchers Richard Young and Michael Vecchione, who detailed the specimen in the Tree of Life Web Project.

The mysterious squid was originally captured in March 1971 by a trawling vessel operating more than a mile beneath the surface of the Atlantic Ocean. Despite being collected over five decades ago, the specimen wasn’t formally described in scientific literature until 2007, when it appeared in a research paper published by Young, Vecchione, and colleagues in the journal Reviews in Fish Biology and Fisheries.

What makes this specimen particularly notable is its extreme rarity. According to the researchers, this individual remains the only documented example of Promachoteuthis sulcus ever found. Scientists had initially delayed publishing their findings in hopes of discovering additional specimens, but no others have been documented in the scientific literature in the years since.

Behind those deceptive “lips” lie beaks, which are standard anatomical features among cephalopods – the group of marine mollusks that includes squids, octopuses, cuttlefish, and nautiluses. Cephalopod beaks function similarly to those of birds but are made of hard chitin rather than bone. They’re used for capturing and consuming prey, often with surprising efficiency for their size.

The confusion around the squid’s appearance highlights the public fascination with unusual deep sea creatures. The ocean’s depths remain largely unexplored, with estimates suggesting that more than 80% of our oceans have never been mapped, observed, or explored. This vast unknown continues to yield bizarre and unexpected life forms that challenge our understanding of marine biology.

The viral nature of the Promachoteuthis sulcus image also demonstrates how social media can simultaneously spread awareness of rare marine species while sometimes distorting scientific understanding through sensationalized descriptions. Many posts referring to the creature as a “little sea monster” with human teeth have garnered significant engagement, despite the inaccuracy of the tooth comparison.

For marine biologists, rare specimens like this single Promachoteuthis sulcus individual provide valuable insights into the diversity of deep-sea ecosystems. The continued circulation of its image, while sometimes accompanied by misconceptions, nonetheless contributes to public awareness about the strange and wonderful creatures inhabiting the ocean’s deepest regions.

As deep-sea exploration technology advances, researchers hope to discover additional specimens of this enigmatic squid species, which would allow for more comprehensive study of its biology, behavior, and ecological role in the deep ocean environment.