This bear cub showed he has no fear of heights - calmly scaling a large tree at the Oregon Zoo in Portland.

Zookeepers said the two bears, named Timber and Thorn, are captivating visitors as they embrace their natural instincts by scaling the towering Douglas Fir trees within their habitat.

The bears are venturing to the tree summit to indulge in the 'succulent new growth of leaves' as temperatures rise in spring.

Jen Osburn Eliot, overseeing the zoo's Great Northwest area, expressed awe at the cubs' climbing prowess, noting that visitors often spot them from afar even before entering the zoo premises.

Found separately in Alaska, both cubs were rescued and nurtured by state wildlife officials at the Alaska Zoo in Anchorage before finding sanctuary in Portland last December.