Meerkat bands consist
of related and non-kin males and females (Doolan and MacDonald, 1997,
Zoology). Interactions occur in the context of a two separate linear
dominance
hierarchies for males and females. Meerkats are singular breeders, or
cooperative breeders for whom reproduction is limited to the alpha
pair. Meerkat dominance
increases according to age (Doolan and MacDonald, 1997, Behaviour). Subordinates
develop a creeping posture around dominants and often allogroom them
(Doolan and MacDonald, 1997, Zoology). The dominate male tends to
be more aggressive than subordinate males, and
he scent marks up to ten times more often (Clutton-Brock et al., Feb
1998). His enlarged anal scent gland reflects the increase in marking
behavior.
The dominant female
scent marks more than subordinate females as well. Subordinate females
emit submissive calls to the dominant female
(O’Riain et al., 2000). Both male and female dominants tend to
be heavier than other meerkats of the same band. Females can gain the
alpha position in their
natal burrows or by immigrating to neighboring burrows, but males must
disperse to reach the top of a dominance hierarchy. Either sex can also
establish a new burrow (Griffen et al., 2003). Male dispersal decreases
the likelihood of inbreeding.
High predation pressure
causes constant turnover of the dominance hierarchy. When an alpha
animal dies or disappears,
competition for the
alpha position is immediate and fierce. Once a new dominant meerkat is
established, the fighting stops and the remaining subordinates regain
their position (O’Riain et al., 2000). The hierarchy is strict
and the competition fierce because
reproduction and pup survival depend on helping behavior. The dominance
hierarchy ensures that only one litter is born at a time and that there
are an adequate number of helpers to care for the young. Breeding opportunities
are related to unpredictable weather conditions. If a new dominant weren’t
established soon after the death of the original dominant, a reproductive
opportunity could be missed. The fitness benefits of gaining the alpha
position outweigh the costs of fighting for the position.