Despite sanctions and slow economic growth hindering Russia’s defense efforts, it has recently doubled down on efforts to establish a fearsome Navy, bolstered by powerful new submarine classes like the 170-meter long Borei. Not all of Russia’s naval assets are quite so powerful, however, as demonstrated by the loss of a Russian Navy tugboat named Altai earlier this week.

The Altai, which was assigned to Russia’s Northern Fleet, was sailing to the Franz Josef Land archipelago in the Arctic in support of the Russian Geographical Society. As the boat full of researchers were attempting to conduct an offshore landing (where the researchers and scientists were ferried to shore on smaller boats), a nearby female walrus with young nearby attacked the tug boat.

“During the landing at Cape Heller, a group of researchers had to flee from a female walrus, which, protecting its cubs, attacked an expedition boat. Serious troubles were avoided thanks to the clear and well-coordinated actions of the Northern Fleet servicemen, who were able to take the boat away from the animals without harming them,” Russia’s Northern Fleet said in a statement.

Interestingly, Russian military officials made no mention of the loss of any equipment, let alone the entire vessel. It was the Russian Geographical Society that let the cat out of the bag. Their statement echoed the Russian Navy‘s, while also pointing out that the walrus won its fight with their vessel.

“Walruses attacked the participating boat,” the group explained in a press release. “The boat sank, but the tragedy was avoided thanks to the clear actions of the squad leader. All the landing participants safely reached the shore.”

Walrus can grow to massive proportions, with females like the one in question sometimes exceeding 2,500 pounds. Their sheer size, combined with massive tusks, make them a formidable opponent for nearly any wildlife (or boat) you might find in the Arctic. Walrus mothers will nurse their young for a full year and often remain with them for up to five years before splitting up, and like many other animals, walrus mothers will attack to defend their young. These animals are so large, they’ve even been known to stand and swing with polar bears.

According to some reports, the Russian researchers were using a drone to approach the walrus and her young just prior to the attack, which the walrus must have interpreted as a threat.