February 5, 2013
Meerkat Sentinels Watch For Predators To Protect Their Group
Brett Smith for redOrbit.com — Your Universe Online
[ Watch the Video: Meerkat Predator-Scanning Behaviour Is Altruistic ]
When foraging for food, meerkats often stand on their hind legs or climb to a perch in an attempt to scan for predators and, upon spotting a threat, the animals let out a series of warning vocalizations.
A pair of zoologists from the University of Cambridge in the UK has found the animals perform these behaviors for the good of their group, not just for their own personal safety. The zoologists reached this conclusion by noticing meerkat sentinels were much more vigilant in the presence of young pups.
Meerkats are cooperative by nature, with a dominant breeding pair and as many as 40 male and female ℠helpers´ that do not normally breed, but do assist with a number of activities; such as the babysitting and feeding of offspring.
Despite these pronounced examples of collectivist behavior, scientists have questioned if the meerkats act as sentinels for their own protection, with the group's increased safety being a side effect, or if the primary goal is the deliberate protection of the group.
"You see similar behavior in a range of mammal and bird species, and we know from previous work that other group members are less likely to be attacked by predators when someone is on guard,” said Peter Santema, a PhD student at the University of Cambridge's Department of Zoology. “Biologists have been debating, however, whether the protection that other group members enjoy is just a side-effect or one of the reasons why individuals perform these guarding behaviors."
In the study, the two zoologists observed helper meerkats during the period just before their female´s pups had joined their group on foraging trips. The researchers also recorded their observations of the helpers immediately after the pups joined the group. In addition to watching for the amount of sentinel or vigilance activity, the researchers also recorded the changes in foraging time and amount of food found between the two observation periods.
After comparing these sets of data, the team found the pups´ presence caused the helpers to show a sudden increase in their vigilant behavior. In their report, the zoologists mentioned factors outside their control could have played a role in the increased amount of vigilance.
“For instance, if the presence of pups attracts predators to the group, an increase in sentinel behavior and bipedal vigilance could also result from an increase in predation risk,” they wrote.
The scientists noted the helpers´ dedication to their sentinel duties resulted in them finding less food when pups were in the group. Conversely, this allows the non-sentinel members of the group to reduce their own vigilance, resulting in increased foraging efficiency.
"These results are exciting, as they show us that individuals are not just on the look-out for their own safety, but that the protection of other group members is another motivation for these behaviors,” Santema said. “Our results thus suggest that vigilance and sentinel behavior in meerkats represent forms of cooperation."