Widest gape for a mammal

The common hippopotamus Hippopotamus amphibius of sub-Saharan Africa including South Africa and eastern Africa has the widest gape of any mammal, as it is able to open its jaws to a remarkable 150°. This is more than 100° greater than the gape that a human can achieve (45°). The common hippo's mouth can yield this huge gape due to its jaws being hinged far back in its skull. The pygmy hippo can also yield a very wide gape, but smaller than that of the common hippo.

It is often claimed that the presumed-extinct thylacine or Tasmanian wolf Thylacinus cynocephalus, whose last confirmed specimen died in Hobart Zoo in 1936, had the widest gape among mammals, with claims of 120° and even up to 180° having been alleged, and a rare video of a living specimen gaping demonstrates that this deceptively wolf-like marsupial could certainly open its mouth wide. However, examination of its jaws' anatomy using preserved skulls reveals that their structure would not have enabled the thylacine to gape wider than 80°, thereby falling far short of that of the common hippopotamus.