It is June in the Alaskan Arctic and two grizzlies are traversing the tundra at an hour that would, at lower latitudes, be dawn. One, a blonde, ambles along a riverbank, light from the already-high sun glinting off her massive haunches. The other, chocolate-coloured, is loping to catch up with her, his heaving breath audible from your correspondent’s seat at the mouth of her small tent. Though she is camping on the other side of a frigid river, its channel is narrow enough to be a moment’s swim for a bear so inclined. Thankfully humans are incidental to these grizzlies’ morning. The dark bear reaches the blonde. They mate and loll, briefly, then lumber up a hill, over a ridge and vanish.