Hiking equipment
According to Tom Brown, the basic plan for survival is in the order of shelter (including clothing), water, fire, and food. Cody Lundin writes about the "Rule of 3s"; this relates to human survival without basics: three minutes without air, three hours without shelter, three days without water, or three weeks without food.
Narwhal
Narwhals can live up to at least 50 years. Mortality often occurs when the narwhals suffocate after they fail to leave before the surface of the Arctic waters freeze over in the late autumn. As narwhals need to breathe, they drown if open water is no longer accessible and the ice is too thick for them to break through. Maximum aerobic swimming distance between breathing holes in ice is less than which limits the use of foraging grounds, and these holes must be at least wide to allow an adult whale to breathe. The last major entrapment events occurred when there was little to no wind. Entrapment can affect as many as 600 individuals, most occurring in narwhal wintering areas such as Disko Bay. In the largest entrapment in 1915 in West Greenland, over 1,000 narwhals were trapped under the ice.