Survivability in harsh and unfavourable environments is especially critical during parturition and during the neonatal period, when there is a greater chance of ewe and lamb mortality. This is especially true for extensively managed animals such as hill compared to lowland (intensively managed) breeds of sheep. The extensively managed sheep have to have different behavioural and physiological adaptations that enable them to survive. Some of the differences between hill and lowland sheep are as follows: hill sheep have smaller average litter sizes than lowland sheep, but their litters are significantly heavier. Maternal experience and knowledge of the environment will affect isolation seeking at parturition. Domestication seems to have had an effect on isolation seeking. This behaviour has decreased in intensively managed breeds. The extensively managed breeds have a shorter labour, and an easier delivery than intensively managed breeds. The hill (extensive) breeds also lick their lambs more after birth and perform more low-pitched bleating than lowland ewes. These differences in behaviour result in hill breeds having better ewe-lamb recognition and closer spatial relationships. The hill ewes are also more aware of their during lactation, which could also be a useful protective measure against predators. Hill lambs stand and suck faster after birth and show greater maternal recognition than lowland lambs. Hill lambs are more tolerant of cold temperatures, due to birthcoat characteristics, higher thyroid concentrations and possibly due to the higher lipid content in the colostrum. Compared to lowland sheep, the behavioural and physiological mechanisms of hill sheep have evolved to ensure lamb survivability in harsh environments.