Body of Dolphin "Teoki" Found After 7 Years of Survival Despite Oral Cancer

Jaw Deformation Attributed to Malignant Diseases Like Oral Cancer
Survived Seven Years on Small Prey... "A Symbol of Hope"

Jeju's Indo-Pacific bottlenose dolphin known as "Teoki," who survived for more than seven years despite being unable to close its mouth due to oral cancer, has been confirmed dead.

According to Yonhap News, citing Professor Kim Byungyeop of the Jeju National University Whale and Marine Life Conservation Research Center and Director Oh Seungmok of Daqoo Jeju, Teoki's carcass was discovered on June 2 in the waters off Jungmun, Seogwipo, Jeju. The report was published on June 5.

Teoki was first discovered in 2019 in the waters off Jeju. The dolphin was named "Teoki" due to its deformed appearance, with a twisted snout, an inability to close its mouth, and a protruding tongue.

Experts speculated that Teoki's jaw was deformed due to malignant diseases such as oral cancer. Director Oh stated, "Even at the time of discovery, it was presumed that Teoki was suffering from oral cancer and had been battling the disease for a considerable period."

The jaw (lower part) of a Indo-Pacific bottlenose dolphin captured in September 2022. Provided by Jeju National University Whale and Marine Life Conservation Research Center and Daqoo Jeju.

Because Teoki lost jaw function, it was difficult to sever and consume larger prey, which limited its diet. However, studies found that Teoki survived for seven years by mainly feeding on flatfish, which are relatively easy to catch, near fish farms in the southwestern area of Seogwipo.

At the time, an animal protection group representative noted that cetaceans are generally not prone to cancer and have excellent wound healing abilities. The representative expressed concern, stating, "This raises worries about whether the coastal waters of Jeju are becoming contaminated with toxic chemicals and carcinogens."

Until the day before the carcass was found, Teoki was observed swimming off the coast of Mureung-ri, Daejeong-eup, showing no unusual signs.

At the time the carcass was discovered, Teoki measured approximately 209 cm in length and was in relatively good condition. There were some scratches, but decomposition was not severe.

Currently, the carcass is being stored at the Korea Fisheries Resources Agency Jeju Regional Headquarters' freezing facility in Ungpo-ri, Hallim-eup. The Jeju National University Whale and Marine Life Conservation Research Center plans to conduct a necropsy as early as mid-July to determine the exact cause of death, confirm the presence of disease, and record the findings for academic purposes.

Director Oh stated on his social media, "Although the exact age is unknown, Teoki's resilient presence was a symbol of hope for overcoming disability to researchers and citizens who watched over him. I hope Teoki's soul rests peacefully in a beautiful place."