Watch this amazing footage of his close relationship with this magnificent creature.
Casey insists the creatures (grizzly bears) are similar to humans in that they are intelligent, have personality, and according to him can even shed tears.
It is his passion for the creatures that sparked Anderson to set out on a year-long mission to chronicle the lives of Yellowstone National Park bears.
Together with National Geographic, Expedition Grizzly aims to dispel the negative stereotypes surrounding the bears and chart the impact humans have had on their environment.
In the documentary, which is due to air on National Geographic on May 3, Anderson lives among the bears, often in extreme conditions as he observes their behaviour. Read more
WATCH Casey get up close and personal with grey wolves of Yellowstone: