A female walrus has attacked a Russian Navy boat, causing it to sink.

The walrus attacked a navy landing boat while it was exploring the Arctic Ocean last week, sending it to the bottom of the ocean, CNN reports.

The Russian Ministry of Defense says the walrus was protecting her calves when the incident occurred. 

Members of the Northern Fleet and Russian Geographic Society were on board the boat for the incident. The RGO said those on board reached the shore safely and nobody was injured.

The sailors were in the area to investigate flora and fauna in the arctic, as well as glaciers.

"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," the ministry said.

"The incident is another confirmation that no one is expecting humans in the Arctic," the Russian Geographic Society said.