They can't
Geese in Northern Canada can live there in the summer. As it gets cold, they move south to more hospitable weather. But it's a losing action! With many more geese, there would be mass extermination. Ah, but the geese in southern Canada migrate (invade) Northern USA. The pattern continues as if all the geese were part of one hand that moves its small finger out of the cold one month and then moves its thumb out of the heat months later. The whole hand moves just to accommodate the small finger and then the thumb. So it is with geese. This forms a model for other species that migrate.
Migration helps animals survive in extreme conditions by providing them with access to food, a less harsh climate, or better protected area in which to breed or to have offspring. Many animals migrations are linked to those of other animals, for example some animals at the top of the food chain will follow packs of other animals they use as a main source of food.
While there are organisms that can live for long periods of time and organisms that can survive extreme conditions, there is no organism that is immortal. Unless God counts.
they survive in extreme conditions
Some organisms are better at adaptation to their environment because of their size, their diet, or any number of other reasons.
The term used to describe organisms that can survive in severe conditions is extremophiles. Extremophiles are able to thrive in environments with extreme temperatures, pH levels, salinity, pressure, or other challenging conditions that are typically uninhabitable for most forms of life. Examples of extremophiles include bacteria living in hot springs, organisms in deep-sea hydrothermal vents, and lichens in arid deserts.
Extreme temperatures
some can and some cannot
A jaguar survives in extreme weather because of it's thick fur.
Root modifications are modifications of the roots that help them to survive in extreme conditions
Lichens grow extremely slowly. Lichens are able to survive extreme conditions.
hibernation
organisms on one extreme of the population have a better chance to survive than do those on the other extreme.