This story was originally published in Wired and appears here as part of our Climate Desk collaboration. Researchers have long debated what the 10-foot-long tooth that erupts from a narwhal’s head is actually for. Perhaps it has something to do with sexual selection, and males with longer horns attract more females. Or maybe the things sense salinity. Or perhaps a narwhal uses its tusk to flush out prey on the ocean bottom. Whatever the purpose, scientists know this for certain: The Arctic region, which the narwhals call home, is warming…
