The Short-Faced Bear: America's Top Predator 

The short-faced bear (Arctodus spp.) is an extinct bear that inhabited North America during the Pleistocene epoch from about 1.8 Mya until 11,000 years ago. It was the most common early North American bear and was most abundant in California. There are two recognized species: Arctodus pristinus and Arctodus simus, with the latter considered one of the largest known terrestrial mammalian carnivores. It has been hypothesized that their extinction coincides with the Younger Dryas period of global cooling commencing around 10,900BC. It has been proposed that a large air burst or earth impact from one or more comets from outer space impacted North America, initiating the Younger Dryas, which caused wildfires and environmental catastrophes led to the extinction of North American Pleistocene megafauna, including the short-faced bear together with the demise of the Clovis culture.