Migration allows acclimation to the changing salinity. Both thermal sensitivity levels and nociceptive thresholds change with changes in acclimation temperature. They often have trouble tolerating cold weather without careful acclimation. This prepares the plant for seasonal acclimation to the cooler temperatures. Acclimation boosted the temperature needed to kill half of active tardigrades to . The changes in temperature and acclimation are complex. This follows the climber's adage "climb high, sleep low", and helps altitude acclimation. Are changes in enzyme activities of fish muscle during cold acclimation significant?. This idea has come to be known as the beneficial acclimation hypothesis. A hostile environment will directly counter acclimation and feeding efforts. He is also known as one of the first testers of the beneficial acclimation hypothesis. Additionally, one of the doctors said that "total acclimation (to the Qatari climate) is impossible". The zebras were removed four months after their arrival due to "acclimation" issues. It is an example of mechanical acclimation in trees. However, there are likely to be costs associated with acclimation.