In July and August each year, tens of thousands of fat salmon migrate back up the rivers of Northern America and Eastern Russia to spawn. For an opportunistic hunter like the brown bear, this is too good to miss.
A bear perched at the top of a low waterfall catching fish in mid air makes for a great photograph, but the right sort of waterfall is relatively rare and competition from other hungry bears at these spots can be very fierce. It also requires perfect reflexes. The bear has just one chance to snatch the slippery, struggling fish with a grip firm enough to make it back to the shore without it wriggling free. If he drops it, the fast-flowing water will whisk away his prize, even if the fish is already dead.
A much better hunting ground is where the river becomes broad and shallow. In ankle-deep water, the bear can outrun the salmon as they frantically flap themselves over the stones, and pinning one to the riverbed with heavy claws is much easier. Bears also watch from the bank as salmon rest in calmer pools close to shore. They will then suddenly leap and try to snatch a fish in their jaws.
The bear’s fearsome claws may be deadly weapons on land, but against salmon they aren’t much use. Bears don’t have opposable thumbs so they can’t grip the fish and brown bear claws are quite blunt. But they have very powerful jaws with huge, backward-curving canine teeth. Bears will attempt to snag the fish with the front of the mouth when they strike, but they will often then hold the fish against the crook of their elbow. This lets them get a better grip on the salmon with the molars at the back of the mouth, so they can securely carry it to the shore.