This is the moment a grizzly bear chases a smaller black bear that has to climb up a tree to get away.

The incident was filmed at Glacier National Park in the north-western US state of Montana on the US-Canada border, and the footage has been viewed over 120,000 times on Facebook.

The national park said: “Check out this amazing video of grizzly and black bears interacting from visitor Anthony James!

“Normally agreeable when food is abundant, grizzly and black bears run into one another more often when food is scarce – like early summer.

“While grizzly bears are larger and typically stronger than black bears, this black bear displays its powerful exit strategy: Climbing!”

Glacier National Park added: “The short, sharp claws of the black bear are ideal for tree climbing. The grizzly’s longer, duller claws are great for digging, but poor for climbing – especially because an adult grizzly is substantially heavier than a black bear.”

According to the National Park Service, there are around 600 black bears and 300 grizzly bears, also known as the North American brown bear, in Glacier National Park.

The National Park Service advises visitors to remain at least 100 yards from any wolves or bears in the park, adding: “Never intentionally get close to a bear. Individual bears have their own personal space requirements, which vary depending on their mood. Each will react differently and its behaviour cannot be predicted.”

Facebook user ‘Charley Emmerson Brewer’ said: “Bears doing what bears normally do.”

Netizen ‘Eric Robinson’ commented: “That’s so cool. I thought the grizzly might shake the tree to dislodge the black bear. Guess it wasn’t a matter of that much importance!”

‘Linda Cooper’ wrote: “Ha! So escaping from a bear by climbing a tree… maybe not. Great video from a distance!”