One Gentoo Penguin Walked Into a Genome Sequencer. Four Came Out.

There is a penguin living on the Kerguelen Islands, almost 2,000 miles (3,200 kilometers) from the nearest permanently settled land. The French call the place the Desolation Islands. Apart from slight differences in size and voice, the bird could pass for any other gentoo, which is how it went unrecognized.

Biologists call that a cryptic species, one that is genetically distinct but nearly identical to the eye. A team led by scientists in Chile and at UC Berkeley sequenced gentoo genomes and reported in Communications Biology that the single wide-ranging gentoo is really four species. The Kerguelen bird is the first penguin species to be newly named in more than 100 years.

The cause the researchers propose is almost embarrassingly mundane. Gentoos will eat nearly anything they can catch, from krill to cuttlefish, so they rarely stray from the colonies where they breed. Stay home long enough, across enough generations, and geography does the taxonomic work for you.

The result is four lineages: northern gentoos from South America and the Falkland Islands; southern gentoos from Antarctica; eastern gentoos from Crozet, Marion and Macquarie Islands; and southeastern gentoos from the Kerguelen Islands. Three of the four face an uncertain future as climate change reshapes their sub-Antarctic habitat. The exception is the southern gentoo, Pygoscelis ellsworthi, the one species living in Antarctica, which is projected to hold steady or even gain ground as its range expands.

Rauri Bowie, a UC Berkeley biologist and co-senior author, said the gentoo may be the most argued-over penguin in taxonomy, with the number of species and subspecies in dispute for more than 100 years.

Three were subspecies waiting on a promotion. The fourth, Pygoscelis kerguelensis, was waiting on a name.

Read the full story at UC Berkeley Research, May 8, 2026

Hot Take: Count the gentoo as one species and the tally looks healthy, because the Antarctic birds are increasing. Taxonomy isn't just bookkeeping; sometimes it's the thing standing between a species and a status report that says everything is fine.