Danish researchers have sequenced the genome of a narwhal, the Arctic whale famous for the horn-like tusk protruding from its forehead. Their work, appearing May 1 in the journal iScience, finds that compared to other Arctic marine mammals, narwhals have low genetic diversity, which typically indicates a species is struggling. However, narwhal populations number in the hundreds of thousands -- but researchers warn they are still vulnerable to climate change and human activities in the Arctic.
