Douglas Mawson and Xavier Mertz were part of the Far Eastern Party, a three-man sledging team with Lieutenant B. E. S. Ninnis, to survey King George V Land, Antarctica. On 14 December 1912 Ninnis fell through a snow-covered crevasse along with most of the party's rations, and was never seen again. Their meagre provisions forced them to eat their remaining dogs on their 315-mile (507 km) return journey. Their meat was tough, stringy and without a vestige of fat. Each animal yielded very little, and the major part was fed to the surviving dogs, which ate the meat, skin and bones until nothing remained. The men also ate the dog's brains and livers. Unfortunately eating the liver of sled dogs produces the condition hypervitaminosis A because canines have a much higher tolerance for vitamin A than humans do. Mertz suffered a quick deterioration. He developed stomach pains and became incapacitated and incoherent. On 7 January 1913, Mertz died. Mawson continued alone, eventually making it back to camp alive.