Andrewsarchus mongoliensis, was a mammal that lived during the Eocene epoch, roughly between 45 and 36 million years ago. It had a long snout with large, sharp teeth and flat cheek teeth that may have been used to crush bones. 

The appearance and behavioural patterns of Andrewsarchus are virtually unknown. All that is known about Andrewsarchus comes chiefly from the single, nearly perfectly preserved three-foot-long skull found in Late Eocene sediments in what is now Mongolia. An estimated weight of 1000kg, it is unknown whether Andrewsarchuswas an active predator or merely a large scavenger.

When the Indian subcontinent collided with Asia during the Late Eocene/Early Oligocene, this event caused the formation of the Himalaya mountains while closing off the eastern Tethys Ocean, thus changing weather patterns, and caused Central Asia to dry out, ultimately resulting in a dramatic faunal turnover. It is suggested that Andrewsarchus became extinct due to this.

(Source: thepredatorblog)