The spectacled cormorant was a large-bodied seabird first discovered on Bering Island in the 18th century. It was believed to have only existed on this one island in the northern Pacific Ocean, before being hunted to extinction after Bering Island was colonized by humans in the early 1800s. But scientists have now made an exciting discovery – no, the species is still extinct – but researchers from Kyoto University have found that this bird also resided in Japan almost 120,000 years ago.
In a study published in The Auk: Ornithological Advances, the research team reports that this species underwent a significant range contraction or shift, and that the specimens found on Bering Island are “relicts” of a species that was once more widespread.
“Before our report, there was no evidence that the cormorant lived outside of Bering Island,” says Junya Watanabe of Kyoto University’s Department of Geology and Mineralogy, and first author of the study.
The research team studied bird fossils recovered from Shiriya, identifying 13 bones of the spectacled cormorant from upper Pleistocene deposits, which formed almost 120,000 years ago.
“It became clear that we were seeing a cormorant species much larger than any of the four native species in present-day Japan,” explains co-author Hiroshige Matsuoka. “At first, we thought this might be a new species, but these fossils matched bones of the spectacled cormorant stored at the Smithsonian Institution.”
It is thought that changes in oceanographic conditions could have been responsible for the disappearance of the species in Japan. Previous paleoclimate studies have found that oceanic productivity near Shiriya decreased significantly in the Last Glacial Maximum, which occurred roughly 20,000 years ago. These changes may have dramatically affected the cormorant population.
“The cormorant was a gigantic animal, its large size thought to have been achieved through adaptation to the island-oriented lifestyle on Bering,” says Watanabe. “But our finding suggests that this might not have been the case; after all, it just resided there as a relict. The biological aspects of these animals deserve much more attention.”
The study of extinction events such as this are necessary for us to better understand how natural disturbances affect species – especially in our changing climate. It’s possible that studying the past may ultimately save our future.