According to a group of biologists at the University of Manitoba, black-tailed prairie dogs (Cynomys ludovicianus) test the alertness of their neighbors with contagious jump-yip display.
The black-tailed prairie dog, Cynomys ludovicianus. Image credit: John & Karen Hollingsworth.
Black-tailed prairie dogs are large, short-tailed burrowing rodents with eyes and small ears set far back on their heads. They measure up to 40 cm long and weigh as much as 0.5 – 1.5 kg.
These rodents are social and live together in large aggregations, called colonies or towns, on the North American grassy plains and prairies in a range that stretches from Canada to Mexico.
Their colonies must be constantly vigilant to detect predators. However, sharing the responsibilities for keeping watch means prairie dogs need to collect up-to-date information about how alert other members of the group are.
The new study, published in the Proceedings of the Royal Society B, suggests that the jumping display of the prairie dog, the ‘jump-yip’ which is accompanied by a ‘wee-oo’ sound, is used to see if other members of the social group are paying attention. The jump-yip is a contagious behavior which spreads though the community like the Mexican wave around a sports stadium as neighboring prairie dogs respond by copying the display from each other.
Biologists have speculated in the past that its purpose could be to mark territory, give an ‘all clear’ signal or promote social bonding.
But the authors of the new study hypothesized that the jump-yip is used to probe how alert other individuals in the group are. This could help determine the risk of a prairie dog reducing their own vigilance to forage for food.
The team studied how the responsiveness of the colony to the jump-yip affected how vigilant the instigating prairie dog was for one minute after the display.
Vigilant prairie dogs take on an upright posture, so when the prairie dogs had their heads above the horizontal plane they were observed to be alert and when below they were treated as foraging.
To assess how responsive the group was the team measured the total time that the wave lasted, the number of individuals who responded to the initial jump-yip, and the time it took them to respond.
The findings showed that though the time taken to receive a response had no significant effect on the behavior of the instigator, the longer the wave lasted and the greater the number of prairie dogs who responded to the display the less vigilant the instigating prairie dog was afterwards.
The team found that instigators of the jump-yip wave increased the proportion of time they spent foraging, decreasing the proportion of time they were vigilant, as the responsiveness of other prairie dogs increased.
“It is not surprising that these highly social animals have evolved coordinated social behavior and commensurate cognitive abilities promoting their success in the face of intense predation pressure,” lead author Dr Robert Senkiw and his colleagues said.
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Hare JF et al. 2014. Catch the wave: prairie dogs assess neighbours’ awareness using contagious displays. Proc. R. Soc. B, vol. 281, no. 1777; doi: 10.1098/rspb.2013.2153
