Popularized by the character Timon in the animated Disney film "Lion King," meerkats are often viewed as meek animals constantly on the lookout for danger. But within their small groups, these creatures are anything but meek — including when it comes to their mating behaviors.
Meerkats (Suricata suricatta) live in complex, hierarchical social groups or "mobs" consisting of two to 50 individuals. These groups are ruled by a dominant male and female, called the alpha pair, that have exclusive breeding rights. The group also contains subordinate females who are typically closely related to the dominant female; subordinate males who are usually the offspring of the alpha pair; and one or more unrelated immigrant males.
Meerkats reach sexual maturity at 1 year old, and males willingly leave their group permanently at around 2 years old to attempt to join or take over another group. Adult subordinate females, on the other hand, are often forcefully (and sometimes violently) evicted by the dominant female — they'll sometimes remain on the group's territory, sleeping and foraging alone or with other evicted females until the dominant female's aggression towards them subsides. [Strange Love: 11 Animals with Truly Weird Courtship Rituals]
Some females don't return to the group and instead form new groups, sometimes becoming the alpha female, said Tim Clutton-Brock, a zoologist at the University of Cambridge in the United Kingdom. A female may alternatively become alpha by inheriting the position in her natal group upon the death of the previous alpha (by being the largest and most powerful subordinate).
"And it's very common that the breeding males in groups are the ones that have fought and evicted other males," Clutton-Brock told Live Science.
Dominant females don't have much choice in their mate, given that the dominant male will do all he can to prevent her from mating with immigrant males in the group. And the dominant male will usually only mate with the dominant female, because the other sexually mature females in his group are his offspring.
Similar to humans, meerkats are able to breed year-round. But in their native home range in southern Africa, mating often coincides with periods of high rainfall, Clutton-Brock said, adding that "the rainfall is unpredictable but it's lowest between April and July."
Given that mating typically occurs underground, it's unclear if meerkats engage in many courtship rituals. In some cases, the dominant male may fight with the dominant female and grip her by her nape until she subdues and allows him to mount her from behind.
Subordinate females may occasionally mate with the immigrant males from within the group or outside of the group. But this sneaky behavior comes at a price — dominant females routinely kill subordinate females' pups and evict the wrongdoers (sometimes while the subordinate female is pregnant, forcing her to abort).
As payment for their misdeeds, subordinate females that lose their litters or return to the group after being evicted act as wet nurses for the dominant female's pups.
The dominant female has up to four litters a year and will often remain in her position until her death. When that happens, the remaining females will fight for the ruling seat, with the biggest female often coming out ahead. The ultimate winner will experience spikes in testosterone and estrogen, as well as a rapid increase in weight and skeletal size, in the three months after taking over, Clutton-Brock said.
Interestingly, recent research shows that subordinate meerkat sisters in a group actively compete with each other through eating. In experiments, Clutton-Brock and his colleagues fed younger sisters lots of food to increase their size. Older sisters responded by eating more on their own to grow bigger, helping them keep their place in the queue for the crown and the right to breed.