Begging meerkat pups

Meerkats, © Roberta Stacy

Learning about animal behavior never fails to fascinate me, and so it was with great interest that I read a recent paper on how meerkat pups alter their food-begging behavior depending upon the adult meerkat that they are nearest to. {1}  Not all adults are created equal, it seems, in the world of a meerkat pup. And because these creatures are cooperative breeders, pups aren’t “stuck” with their birth parents. They have their choice of food-givers to hit up for a meal. Even better, some adults dole out food at a higher rate than others — leaving scientists wondering if the pups were preferentially seeking them out in order to maximize their food intake. Evolutionarily, it would make sense that a clever pup would hone in on the foodiest adult and put on a begging show, but that isn’t exactly what the researchers found.

But before I go into the paper, let’s spend a few words on what meerkats are and where they live. Meerkats belong to the mongoose family and they live in southern Africa in the Kalahari desert. They are slinky, social, carnivorous mammals that resemble a cross between a weasel and a prairie dog (at least, I think they do). Dark fur rims their eyes, functioning like sunglasses to help them see better in their sunny desert habitat. Their claws are non-retractable and they have the unique ability to close their ears. They live 12 to 14 years, and have adapted to changing desert temperatures by using their thinly furred bellies as solar panels to warm themselves when the ambient air temperature is too cool. Meerkats live in groups of 2 to 50 animals, usually with one socially dominant breeding pair, and many subserviant non-breeding pairs and helpers. The breeding pair may produce two to six pups per litter, and have two to four litters per year. Many photographs show them standing on their hind legs, depicting a guardian or lookout stance that the social animals use to keep an eye out for predators and to protect their group. They are the perfect meal size for martial eagles and jackals, their main predators.

Meerkat, Suricata suricatta, adult with juvenile.

Meerkats make their home in underground burrows, and various members of the group will care for newborns and pups to allow the mothers time to feed. And it is this last characteristic that was the focus of a recent study on how meerkat pups beg for food, and how the parents and group caregivers respond. Joah Madden and his team wrote that most studies on begging behavior have focused on birds confined to nests. But because the meerkat pups can move themselves around between various adults, it follows that they may have adaptive begging strategies. For example, perhaps they seek out the adults that give food at higher rates, or perhaps they beg at higher rates when near higher-provisioning adults. So Madden’s team posed the question: “Do the young choose which adult to associate with and what level of begging to exhibit, depending on specific attributes of the adult?” They also sought to determine if the pups wereactively seeking out higher-provisioning adults based upon how hungry they were, or if the differing begging strategies were merely an adaptive reaction to the adult’s behavior (that is, if the pups begged more in reaction to adults that gave food at higher rate).

And what yummy food it is that these pups sought! According to Fellow Earthlings Wildlife Center in California — a non-profit licensed to care for meerkats — they eat “Scorpions (meerkats are immune to their venom), beetles, spiders, centipedes, millipedes, worms, crickets… small mammals, small reptiles, birds, eggs, tubers and roots.” Quite a scrumptious menu, if you are a meerkat! Pups are fed by their parents and other caregivers for the first 25 days of their lives, and then they begin to forage with adults. They move freely between all adults in their group, and continue to beg. Adults typically feed the pup that is physically closest to them — a pattern that continues for about three months.

So the researchers set out to test whether these mobile beggers were 1.) strategically seeking out higher-provisioning adults, 2.) if they were adjusting their begging behavior based upon the “identity of the adult” nearest to them, and 3.) if this behavior had any net benefit to the pups’ dietary intake. They also wanted to determine if the adults changed their feeding behavior based upon the pups’ begging rate, and whether the pups or the adults ultimately controlled the associative patterns of feeding. Using hair dye to mark individual wild meerkats at a site near the Kuruman riverbed in the Kalahari desert, the team recorded pup vocalizations (begging) and adult responses within a 10-day time period. They tested the association patterns by physically picking pups up and relocating them next to a different adult, then observing its behavior. They found that pups did change their begging behavior by increasing it up to 80 percent more when near adults that doled out food at the highest rate versus those that gave the least. They also found that “Pups begged relatively consistently when next to specific adults,” which seem to show that there is a adaptability strategy in the way the pups begged.

Meerkats, National Geographic wallpaper. Image by Mattias Klum.

Interestingly, their results also show that pups begged at the highest rates to the highest-provisioning adults and spent more time next to these adults, but they found no evidence that the pups were actively seeking out these food troves. They found no evidence that the adult’s sex, body size or social status had any effect on the pups.  The authors state that the adult’s relative feeding rate varies little day to day within a litter, and that the pups begging behavior was dependent upon the identity of the adult that they begged next to. In short, it was the adult’s previous food donations (within the previous 10 days) that most influenced the rate at which pups begged — they begged at a higher rate when next to adults who had previously fed them at a higher rate.

But by conducting “displacement experiments,” where researchers picked up pups and moved them near to other adults, they were able to show that the pups did not “trade-up adults” in order to get nearer to adults who doled food out at higher rates. I was kind of surprised by this finding, because it would seem logical that if the pups have the ability to modulate their behavior based upon the adult they are nearest to, in order to maximize their food pay-off, then they would also be seeking out these pay-offs. Madden and his team acknowledge that this finding may be an artifact of their experiment (physically handling pups and disturbing or confusing them, thereby obviating a wild response or evoking an unnatural one).

The team also concluded that it was most likely the adults who controlled the association patterns, with the higher-provisioning adults seeking out hungry pups that then beg at a higher rate to counter their empty tummy. It sounds like a an elegant idea, and they suggest that the adults size-up the pups overall mass to determine whether or not to keep feeding it more.

If this is true, then the pups begging behavior is just a by-product of the pattern controlled by the adults, and pup mass is a greater predictor of the rates at which adults will feed it than is the pups specific request for food. Talk about tough love… and for all for a savory scorpion.

NOTES:
{1} Joah R. Madden, et al. 2009. Do meerkat (Suricata suricatta) pups exhibit strategic begging behaviour and so exploit adults that feed at relatively high rates? Behavioral Ecology and Sociobiology. 63:1259–1268.