Study Redefines the Monk Seal Family Tree

   Caribbean monk seal specimen collected in Matanzas, Cuba. (Image: Henry W. Elliott/US National Museum)

What’s in a name? Quite a bit when it comes to monk seals, says Sergios-Orestis Kolokotronis, Ph.D., assistant professor in the Department of Biological Sciences. 

Kolokotronis is the co-author of a recent study in the journal Zookeys that has named the first new genus of modern pinnipeds (seals, sea lions, and walruses) in more than 140 years.

Until the 1950s, he said, there were three identified species of monk seals—the Hawaiian, the Mediterranean, and the Caribbean—and it was assumed that all three were closely related. The Caribbean monk seal was last seen in the early 1950s, the victim of overhunting and possibly disease. 

The study, however, has found that the relationship between the three species is far more distinct than was previously thought. As both the Hawaiian and Mediterranean seals are now dangerously close to extinction (numbering just 600 and 1,200 respectively), that distinction is cause for intensified alarm for the remaining two species. 

Using museum specimens of the extinct Caribbean seal, researchers from the Smithsonian, the Leibniz Institute in Berlin, and Fordham conducted DNA analysis and skull comparisons that allowed them to clarify the extinct Caribbean species’ exact spot in the monk seal family tree. And it’s pretty far from its cousin in Hawaii, and even farther from its Mediterranean brethren. 

The Atlantic and Pacific monk seals swam freely between North and South America some 3 to 4 million years ago before tectonic shifts closed the Isthmus of Panama. At that time, they split and evolved into distinct species. 

“By studying recently extinct species, those whose disappearance is due to human intervention and hunting, we can understand the living species better,” said Kolokotronis, “and surmise what obstacles they may face.”

He noted that while the cause for concern was substantial, there was a school of thought among some biodiversity specialists that if the numbers dwindled further, perhaps a transfer of the Hawaiian species to the Mediterranean species could help with repopulation.  

“People thought, ‘It’s OK if [one species] goes extinct because we can translocate,’” he said. “But we need more careful research. This should intensify intergovernmental collaboration to save about-to-go-extinct species.” 

Unfortunately, there is little or no talk among the countries to actively save the animals, he said. And while the findings and conclusions are impressive, there’s little cause for celebration in watching a species’ demise. 

“We gain nothing by just documenting the populations as they go extinct and not doing anything substantial,” he said. Read more on Kolokotronis' research here.

-Tom Stoelker