Activity pattern of arctic reindeer in a predator-free environment: no need to keep a daily rhythm.
Arctic Cervids face considerable challenges in sustaining life in a harsh and highly seasonal environment, and when to forage is a key component of the survival strategy. We predict that a cervid maximizes net intake of energy to change the duration of feeding-ruminating cycles depending on season, and pays no attention to light or other activity-entraining cues. Still, in periods of bad weather it may pay energetically to reduce exposure and heat loss. We investigated environmental impact on the seasonal and daily activity pattern of a food-limited, predator-free arctic deer, the Svalbard reindeer. We found that the reindeer indeed had season-dependent feeding-rumination intervals, with no distinct peaks in activity at sunrise and sunset, as would be expected if animals maximize energy intake rates in predator-free environments. However, they temporarily reduced activity when exposed to low temperature and increased precipitation during winter, possibly to conserve energy. We provide insight into the behavioural strategy of Svalbard reindeer which enables them to cope with such an extreme environment.
Loe
Leif Egil
LE
Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, P.O. Box 1066 Blindern, 0316, Oslo, Norway.
Bonenfant
Christophe
C
Mysterud
Atle
A
Severinsen
Torbjørn
T
Oritsland
Nils Are
NA
Langvatn
Rolf
R
Stien
Audun
A
Irvine
R Justin
RJ
Stenseth
Nils Chr
NC
D000818:Animals; D001110:Arctic Regions; D001522:Behavior, Animal / Q000502:physiology*; D017753:Ecosystem; D009043:Motor Activity / Q000502:physiology*; D010507:Periodicity; D012053:Reindeer / Q000502:physiology*