scholarly journals Predator occurrence and perceived predation risk determine grouping behavior in guanaco (Lama guanicoe)

2020 ◽  
Author(s):  
EC Iranzo ◽  
Heiko Wittmer ◽  
J Traba ◽  
P Acebes ◽  
C Mata ◽  
...  
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Habitat Structure ◽  
Group Cohesion ◽  
Family Group ◽  
Lama Guanicoe ◽  
Low Visibility ◽  
Grouping Behavior ◽  
Perceived Predation Risk ◽  
Family Groups

© 2018 Blackwell Verlag GmbH Grouping behavior of social ungulates may depend on both predator occurrence and perceived predation risk associated with habitat structure, reproductive state, and density of conspecifics. Over 3 years, we studied grouping behavior of guanaco (Lama guanicoe) families in Chilean Patagonia during the birthing season and determined their response to variation in predator occurrence and perceived predation risk (habitat structure, calf/adult rate, and density of conspecifics). We considered the effect of two predators, puma (Puma concolor) and culpeo fox (Lycalopex culpaeus). We measured two common (family group size and vigilance) and one novel (family group cohesion) behavioral responses of guanaco. Our results show that guanaco family groups adapted their grouping behavior to both predator occurrence and perceived predation risk. Larger family groups were found in open habitats and areas with high puma occurrence, while guanacos stayed in small family groups in areas with high shrub cover or low visibility. Group cohesion increased in areas with higher occurrence of pumas and culpeo foxes, and also increased in smaller family groups and in areas with low guanaco density. Vigilance (number of vigilant adults) was mainly related to group size and visibility, increasing in areas with low visibility, while residual vigilance (vigilance after removing the group-size effect) did not vary with the explanatory variables examined. Our results suggest that a mix of predator occurrence and perceived predation risk influences guanaco grouping behavior and highlights the importance of evaluating different antipredator responses together and considering all predator species in studies aimed at understanding ungulate behavior.

scholarly journals Predator occurrence and perceived predation risk determine grouping behavior in guanaco (Lama guanicoe)

2020 ◽  
Author(s):  
EC Iranzo ◽  
Heiko Wittmer ◽  
J Traba ◽  
P Acebes ◽  
C Mata ◽  
...  
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Habitat Structure ◽  
Group Cohesion ◽  
Family Group ◽  
Lama Guanicoe ◽  
Low Visibility ◽  
Grouping Behavior ◽  
Perceived Predation Risk ◽  
Family Groups

© 2018 Blackwell Verlag GmbH Grouping behavior of social ungulates may depend on both predator occurrence and perceived predation risk associated with habitat structure, reproductive state, and density of conspecifics. Over 3 years, we studied grouping behavior of guanaco (Lama guanicoe) families in Chilean Patagonia during the birthing season and determined their response to variation in predator occurrence and perceived predation risk (habitat structure, calf/adult rate, and density of conspecifics). We considered the effect of two predators, puma (Puma concolor) and culpeo fox (Lycalopex culpaeus). We measured two common (family group size and vigilance) and one novel (family group cohesion) behavioral responses of guanaco. Our results show that guanaco family groups adapted their grouping behavior to both predator occurrence and perceived predation risk. Larger family groups were found in open habitats and areas with high puma occurrence, while guanacos stayed in small family groups in areas with high shrub cover or low visibility. Group cohesion increased in areas with higher occurrence of pumas and culpeo foxes, and also increased in smaller family groups and in areas with low guanaco density. Vigilance (number of vigilant adults) was mainly related to group size and visibility, increasing in areas with low visibility, while residual vigilance (vigilance after removing the group-size effect) did not vary with the explanatory variables examined. Our results suggest that a mix of predator occurrence and perceived predation risk influences guanaco grouping behavior and highlights the importance of evaluating different antipredator responses together and considering all predator species in studies aimed at understanding ungulate behavior.

scholarly journals Predator occurrence and perceived predation risk determine grouping behavior in guanaco (Lama guanicoe )

Ethology ◽  
2018 ◽  
Vol 124 (5) ◽  
pp. 281-289 ◽  
Author(s):  
Esperanza C. Iranzo ◽  
Heiko U. Wittmer ◽  
Juan Traba ◽  
Pablo Acebes ◽  
Cristina Mata ◽  
...  
Keyword(s):  
Predation Risk ◽  
Lama Guanicoe ◽  
Grouping Behavior ◽  
Perceived Predation Risk

Does habitat type modify group size in roe deer and red deer under predation risk by Iberian wolves?

2008 ◽  
Vol 86 (3) ◽  
pp. 170-176 ◽  
Author(s):  
I. Barja ◽  
S. Rosellini
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Cervus Elaphus ◽  
Red Deer ◽  
Roe Deer ◽  
Habitat Type ◽  
Capreolus Capreolus ◽  
Antipredator Response ◽  
The Mean ◽  
Grouping Behavior

We examined whether group size in red deer ( Cervus elaphus L., 1758) and roe deer ( Capreolus capreolus (L., 1758)) under predation risk by Iberian wolves ( Canis lupus L., 1758) is affected by the type of habitat in which the deer reside. We hypothesized that group size (i) would be larger in open than in closed habitats, since it is an antipredator response, and (ii) would vary more with habitat type in the species that had higher wolf predation rates. In the study area, wolves were the only predator of wild ungulates, with roe deer being the main target prey. We performed monthly transects along paths to observe the group size of red and roe deer. In roe deer, the mean group size was significantly higher in open than in closed habitats, serving as an antipredator response. However, in red deer, habitat type did not affect group size. The results indicate that under predation risk by wolves the habitat type influences the grouping behavior of roe deer but not red deer. Furthermore, compared with forests, heaths offer less protection from predators and species in this habitat would benefit from larger group sizes.

Perceived predation risk, parasitism, and the foraging behavior of a freshwater snail (Potamopyrgus antipodarum)

1998 ◽  
Vol 76 (10) ◽  
pp. 1878-1884 ◽  
Author(s):  
Edward P Levri
Keyword(s):  
Predation Risk ◽  
Foraging Behavior ◽  
Freshwater Snail ◽  
Potamopyrgus Antipodarum ◽  
Plain Water ◽  
Fish Diet ◽  
Fish Predator ◽  
Size Dependent ◽  
Individual Size ◽  
Perceived Predation Risk

Foraging behavior can be influenced by such factors as predation risk, individual size, and parasite infection. Snails (Potamopyrgus antipodarum) placed in tanks with large rocks were exposed to four types of water: (1) water with crushed snails, (2) water from a tank in which fish (Gobiomorphus cotidianus) were fed only trout chow, (3) water from a tank where the fish were also fed snails, and (4) plain water. Snails could respond by moving to the top of rocks (where algal food was present) or to the bottom of rocks (where the predation risk was lower). The snails responded to fish chemicals by moving to the bottom of rocks. The response was dependent on snail size and fish diet. Smaller snails moved to the bottom of rocks more than larger snails did. Trematode-infected snails were found on top of the rocks more than other classes of snails, but infected snails still moved to the bottom of rocks in response to the fish predator. Snails eaten by fish in the field tend to be smaller than snails in the overall available population. Thus, snails that are more vulnerable to predation respond more intensely to the odor of fish by moving to the bottom of rocks. This size-dependent response to fish appears to be independent of the occurrence of trematode infection.

Hunted hunters? Effect of group size on predation risk and growth in the Australian subsocial crab spider Diaea ergandros

2013 ◽  
Vol 67 (5) ◽  
pp. 785-794 ◽  
Author(s):  
Bianca Unglaub ◽  
Jasmin Ruch ◽  
Marie E. Herberstein ◽  
Jutta M. Schneider
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Crab Spider
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