A walrus, fearing for her cubs, sunk an inflatable landing boat, with Russian scientists on board (Credit: Leonid Kruglov/Rgo.ru)

A female walrus demonstrated the lengths moms — animal and human alike — will go in order to protect their offspring when she sank a Russian research boat that came close to her calves. The incident occurred on September 18, 2019, when a team of sailors and scientists from Russia's Northern Fleet and Geographical Society were sailing to Wilczek Island in the Arctic Ocean.