A study led by Monterey Bay Aquarium Research Institute scientists reported distinct trends in the songs of humpback whales and blue whales.

Blue whales have been singing less, and it could be a bellwether of climate change. Warming oceans affect the availability of their only food source, krill, and according to a study published in the journal PLOS One,

Blue whales are loud. According to the National Oceanic and Atmospheric Administration, they are some of the loudest animals on the entire planet. However, something is changing.