. A dominant female and male reign supreme, dictating the jobs and reproductive rights of all subordinate members. When lower level females do manage to birth their own litter of pups, retaliation is swift and brutal. Alpha females kill those unwelcome, helpless additions to the colony, and, according to new research, then present the bereaved mothers with two options: leave the colony, or earn their keep as wet-nurses for the offspring of their babies’ killer.
. The evictions stress the subordinate females so much that they are less likely to be fertile.
. Evictions by the pregnant dominant female are mainly targeted at older or pregnant subordinate females, and more distantly related females. They occur most frequently in the 20 days before the dominant female gives birth. Evictees remain in the group’s territory and try to join their family again, but are repeatedly attacked by the dominant female and the rest of the group. It has been shown that this leads to weight loss and higher stress hormone levels, but more importantly eviction doubles the probability for an abortion in case the evicted female was pregnant, and it results in a severely impaired ability of the evicted female to successfully conceive. In most cases, evictees are allowed back into the group a few days after pup birth – at a time when pups are considered too old for infanticide by the subordinate.
Based research, there are two probable reasons for evictions:
. The dominant removes competition for her own pups, since it increases the helper/pup ratio and thus the pups’ chance to survive.
. The risk of a pregnant subordinate killing the dominant’s newborn pups is reduced (either because the subordinate cannot reach the pups, or because she is no longer pregnant due to abortion).
Source
http://www.eurekalert.org/pub_releases/2013-10/uoc-ilt100713.php
Source
Source
http://www.sciencedirect.com/science/article/pii/S0003347213004156
Source
http://friends.kalahari-meerkats.com/index.php?id=faq_meerkat_bio