Assuming that the grandmother hypothesis of menopause is correct, speculate on what aspects of a species' behavior and sociality may make menopause likely to evolve. For instance, is it important whether the species is highly social, or whether the species lives in kin groups? Might the age of independence of the young be important? Could menopause ever evolve in a species without parental care, such as aphids or willow trees? As fuel for thought, consider the likelihood of evolution of menopause in (1) orangutans, who live in small groups consisting simply of a female and her dependent young; (2) lions, in which females are very social and remain with their female kin for most of their lives; and (3) Arabian oryx, a species of antelope that lives in small family groups in arid deserts and must sometimes find distant waterholes known only to the older oryx.