This is the moment a black bear saved two of her cubs from a big male bear in Yellowstone National Park.

The rare footage captured among the US wilderness shows the mother bear leading her cubs up a tree away from a male bear in an attempt to keep them out of danger.

“The mother bear not only sent her cubs up a tall tree but also herself! Seeing an adult black bear in a tree is quite a sight!” the filmer wrote online.

Male black bears have been known to kill cubs in order to mate with the female.

In the video, you can hear an onlooker say: “What a good mum! She’s making sure the male is really gone with one last sniff.”

In Yellowstone, feeding in a meadow with her two cubs, a mother black bear becomes aware of an encroaching male. Male black bears can kill cubs in order to force the mother into estrus (fertility) and then mate with her. Watch the mother bear send not only her cubs up a tall tree but also herself! Seeing an adult black bear in a tree is quite a sight! As is seeing her on her hind legs sniffing the air for signs of the male and wailing to warn him off!