It’s been observed in a bunch of mammals, birds, as well as some fish as far as I’m aware. Some theories suggest that it has to do with matriarchal societies or extended familial groups in which the continued presence of the older female contributes to the survival of young even though they themselves can no longer reproduce. But as its been observed in animals in which females provide very little or no reproductive care, this explanation appears too adaptionist in at least some cases. In other words some animals may live beyond their reproductive years simply because of varying rates of aging within the organs of an individual.