An Indo-Pacific bottlenose dolphin mother alternately balances two dead calves on her snout as she moves through waters between Gimnyeong-ri and Woljeong-ri in Jeju on Wednesday afternoon. [Docu Jeju · Jeju National University Whale and Marine Life Conservation Research Center]
An Indo-Pacific bottlenose dolphin mother alternately balances two dead calves on her snout as she moves through waters between Gimnyeong-ri and Woljeong-ri in Jeju on Wednesday afternoon. [Docu Jeju · Jeju National University Whale and Marine Life Conservation Research Center]

Two Indo-Pacific bottlenose dolphin mothers have been spotted off Jeju carrying their dead calves on their heads as they drifted through the sea.

Experts say the unusual phenomenon has raised concerns about the possible impact of ecosystem degradation.

According to the Marine Life Conservation Research Center, Oh Seung-mok, director of Docu Jeju, observed the behavior Wednesday at around 3:20 p.m. in waters between Gimnyeong-ri and Woljeong-ri in Jeju's Gujwa-eup. The dolphins — internationally protected and classified as endangered wildlife — were seen alternately balancing two dead calves on their snouts as they moved through the water.

"It is the first time two have been confirmed in the same frame," Oh said. "Finding even one is shocking, so confirming two at the same time is highly unusual."

Footage captured the two calves at different stages of decomposition. The first calf discovered was emaciated and significantly decomposed, while the second, identified later, still appeared plump and was only beginning to show signs of decay.

Oh estimated the calves died at least three to four days apart, based on factors including water temperature, noting that Saturday through Sunday was the likely window. "Both are believed to be less than a year old," he added.

No external injuries from fishing lines, discarded fishing gear or marine debris were found at the scene. The exact cause of death has not been determined, though disease, suffocation and stress have been raised as possibilities.

The two calves bring to four the total number of Indo-Pacific bottlenose dolphin calf deaths confirmed off Jeju this year. One was found in February off Sagye Port in Andeok-myeon, Seogwipo, another in March off Ilgwa-ri in Hangyeong-myeon, Jeju, and the two most recent off Gimnyeong.

According to Docu Jeju and Jeju National University's Whale and Marine Life Conservation Research Center, calf deaths numbered three in 2023, nine in 2024, five in 2025 and four so far this year. As young dolphin deaths recur annually, concern is growing over a possible link to changes in the coastal ecosystem around Jeju.

Particularly striking is the reluctance of mother dolphins to part with their dead calves. Experts interpret the behavior — in which mothers carry calves on their snouts for days even after recognizing their death — as a form of "funeral behavior."

"Continuing to carry a decomposing calf is not simply movement — it can be seen as performing a funeral," Oh said. He also noted that dolphins believed to belong to the same pod had been observed moving more slowly than usual in recent days around Gimnyeong, Woljeong-ri, Hamdeok and Jongdal-ri.

"The sad funeral of mother dolphins wandering Jeju's waters, unable to let go of their two dead calves, is further evidence that the sea around Jeju is in serious distress," he said.


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