One of the species identified as living at both the North and the South Poles, Pelagonemertes rollestoni, which hunts for its zooplankton prey with a retractable dart attached to its tongue. Its yellow stomach reaches out to feed all parts of its body. Credit Russ Hopcroft, Universtiy of Alaska-Fairbanks, Census of Marine Life.
The Census of Marine Life (COML) continues to produce surprising and cool results. One recently released study, conducted as part of the COML, showed that about 235 species live near both the North and the South Poles, but not in between. Scientists were interested to learn that these species, about 2% of the total number of species living at the poles, were the same at both poles. Genetic studies to determine if the species are still genetically the same, or if they have drifted apart. Although there's no evidence to explain how they ended up so far apart, scientists of course have some theories. It's likely the species originated in the Antarctic, perhaps via deep, cold currents that took larvae north but did not pass into warmer surface waters. But that won't explain why there aren't similar species in between the poles, since presumably the larvae could have lived at the equator in the deeper, colder waters.
Visit the COML website for more pictures of polar oddities.
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