Nonlinear effects of group size on the success of wolves hunting elk
Despite the popular view that social predators live in groups because group hunting facilitates prey capture, the apparent tendency for hunting success to peak at small group sizes suggests that the formation of large groups is unrelated to prey capture. Few empirical studies, however, have tested f...
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ftunivnebraskali:oai:digitalcommons.unl.edu:usgsnpwrc-1320 2023-11-12T04:15:37+01:00 Nonlinear effects of group size on the success of wolves hunting elk MacNulty, Daniel R. Smith, Douglas W. Mech, L. David Vucetich, John A. Packer, Craig 2012-01-01T08:00:00Z application/pdf https://digitalcommons.unl.edu/usgsnpwrc/376 https://digitalcommons.unl.edu/context/usgsnpwrc/article/1320/viewcontent/Mech_BE_2012_Nonlinear_effects.pdf unknown DigitalCommons@University of Nebraska - Lincoln https://digitalcommons.unl.edu/usgsnpwrc/376 https://digitalcommons.unl.edu/context/usgsnpwrc/article/1320/viewcontent/Mech_BE_2012_Nonlinear_effects.pdf USGS Northern Prairie Wildlife Research Center Canis lupus carnivore cooperation free riding group hunting group living interference predation sociality wolf Animal Sciences Behavior and Ethology Biodiversity Ecology and Evolutionary Biology Environmental Policy Life Sciences Recreation Parks and Tourism Administration Terrestrial and Aquatic Ecology text 2012 ftunivnebraskali 2023-10-30T09:54:47Z Despite the popular view that social predators live in groups because group hunting facilitates prey capture, the apparent tendency for hunting success to peak at small group sizes suggests that the formation of large groups is unrelated to prey capture. Few empirical studies, however, have tested for nonlinear relationships between hunting success and group size, and none have demonstrated why success trails off after peaking. Here, we use a unique dataset of observations of individually known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park to show that the relationship between success and group size is indeed nonlinear and that individuals withholding effort (free riding) is why success does not increase across large group sizes. Beyond 4 wolves, hunting success leveled off, and individual performance (a measure of effort) decreased for reasons unrelated to interference from inept hunters, individual age, or size. But performance did drop faster among wolves with an incentive to hold back, i.e., nonbreeders with no dependent offspring, those performing dangerous predatory tasks, i.e., grabbing and restraining prey, and those in groups of proficient hunters. These results suggest that decreasing performance was free riding and that was why success leveled off in groups with >4 wolves that had superficially appeared to be cooperating. This is the first direct evidence that nonlinear trends in group hunting success reflect a switch from cooperation to free riding. It also highlights how hunting success per se is unlikely to promote formation and maintenance of large groups. Text Canis lupus University of Nebraska-Lincoln: DigitalCommons@UNL |
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Open Polar |
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University of Nebraska-Lincoln: DigitalCommons@UNL |
op_collection_id |
ftunivnebraskali |
language |
unknown |
topic |
Canis lupus carnivore cooperation free riding group hunting group living interference predation sociality wolf Animal Sciences Behavior and Ethology Biodiversity Ecology and Evolutionary Biology Environmental Policy Life Sciences Recreation Parks and Tourism Administration Terrestrial and Aquatic Ecology |
spellingShingle |
Canis lupus carnivore cooperation free riding group hunting group living interference predation sociality wolf Animal Sciences Behavior and Ethology Biodiversity Ecology and Evolutionary Biology Environmental Policy Life Sciences Recreation Parks and Tourism Administration Terrestrial and Aquatic Ecology MacNulty, Daniel R. Smith, Douglas W. Mech, L. David Vucetich, John A. Packer, Craig Nonlinear effects of group size on the success of wolves hunting elk |
topic_facet |
Canis lupus carnivore cooperation free riding group hunting group living interference predation sociality wolf Animal Sciences Behavior and Ethology Biodiversity Ecology and Evolutionary Biology Environmental Policy Life Sciences Recreation Parks and Tourism Administration Terrestrial and Aquatic Ecology |
description |
Despite the popular view that social predators live in groups because group hunting facilitates prey capture, the apparent tendency for hunting success to peak at small group sizes suggests that the formation of large groups is unrelated to prey capture. Few empirical studies, however, have tested for nonlinear relationships between hunting success and group size, and none have demonstrated why success trails off after peaking. Here, we use a unique dataset of observations of individually known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park to show that the relationship between success and group size is indeed nonlinear and that individuals withholding effort (free riding) is why success does not increase across large group sizes. Beyond 4 wolves, hunting success leveled off, and individual performance (a measure of effort) decreased for reasons unrelated to interference from inept hunters, individual age, or size. But performance did drop faster among wolves with an incentive to hold back, i.e., nonbreeders with no dependent offspring, those performing dangerous predatory tasks, i.e., grabbing and restraining prey, and those in groups of proficient hunters. These results suggest that decreasing performance was free riding and that was why success leveled off in groups with >4 wolves that had superficially appeared to be cooperating. This is the first direct evidence that nonlinear trends in group hunting success reflect a switch from cooperation to free riding. It also highlights how hunting success per se is unlikely to promote formation and maintenance of large groups. |
format |
Text |
author |
MacNulty, Daniel R. Smith, Douglas W. Mech, L. David Vucetich, John A. Packer, Craig |
author_facet |
MacNulty, Daniel R. Smith, Douglas W. Mech, L. David Vucetich, John A. Packer, Craig |
author_sort |
MacNulty, Daniel R. |
title |
Nonlinear effects of group size on the success of wolves hunting elk |
title_short |
Nonlinear effects of group size on the success of wolves hunting elk |
title_full |
Nonlinear effects of group size on the success of wolves hunting elk |
title_fullStr |
Nonlinear effects of group size on the success of wolves hunting elk |
title_full_unstemmed |
Nonlinear effects of group size on the success of wolves hunting elk |
title_sort |
nonlinear effects of group size on the success of wolves hunting elk |
publisher |
DigitalCommons@University of Nebraska - Lincoln |
publishDate |
2012 |
url |
https://digitalcommons.unl.edu/usgsnpwrc/376 https://digitalcommons.unl.edu/context/usgsnpwrc/article/1320/viewcontent/Mech_BE_2012_Nonlinear_effects.pdf |
genre |
Canis lupus |
genre_facet |
Canis lupus |
op_source |
USGS Northern Prairie Wildlife Research Center |
op_relation |
https://digitalcommons.unl.edu/usgsnpwrc/376 https://digitalcommons.unl.edu/context/usgsnpwrc/article/1320/viewcontent/Mech_BE_2012_Nonlinear_effects.pdf |
_version_ |
1782332896314392576 |