Energy Cost of Running in an Arctic Fox, <em>Alopex lagopus</em>

Abstract

This work was conducted to determine effect of season and starvation on metabolic rate during running in the Arctic Fox (Alopex lagopus) on Svalbard (78°55’N, 11°56’E), Norway. Indirect calorimetry was used to measure metabolic rate of foxes running on a treadmill and heart rate was monitored using implanted radio transmitters. The relationship between heart rate and metabolic rate was also examined. Metabolic rate increased with running speed. In July the metabolic rate during running almost fitted general equations predicted for mammals, while it was up to 20% lower in January, indicating seasonal variation in metabolic rate. There was a significant positive linear relationship between heart rate and weight specific metabolic rate, suggesting that heart rate can be used as an indicator of metabolic rate. Starvation for 11 days decreased the net cost of running by 13% in January and 17% in July, suggesting that a starved fox runs more energetically efficient than when fed. Heart rate measured in July decreased by 27% during starvation. Re-feeding reversed the starvation-induced reduction in metabolic rate and heart rate during running almost up to post-absorptive levels. The present results are from one fox, and must be considered as preliminary data until further studies are conducted.

Local variation in arctic fox abundance on Svalbard, Norway

“…As an example, within 4 days in February 1995, we live-trapped 11 foxes, including four recaptures, while no foxes were captured in 25 traps distributed on Brøggerhalvøya in during the period February-April 1996. Of the 39 foxes live-trapped, 12 (7 adult males, 4 juvenile males, 1 juvenile female) were removed from the population for other studies (Fuglei and Øritsland 1999;Fuglei 2000;Fuglei et al 2000;Fuglei and Øritsland 2001). The increase in the ''Fox Capture Index'' from 1990 to 1995 parallels the increase and stabilisation of the barnacle goose colony ( Fig.…”

Sea ice occurrence predicts genetic isolation in the Arctic fox

“…In conclusion, survival on sea ice and ice floes is a key adaptation in the polar regions because it may greatly enhance the possibility of colonization of remote islands potentially rich in resources but with fewer competitors or predators. Indeed, the Arctic fox can survive long periods without food and they have a low cost of locomotion (Fuglei & Oritsland 1999; Fuglei & Oritsland 2003).…”

Rabies in the Arctic Fox Population, Svalbard, Norway

“…Arctic foxes in Svalbard also belong to the coastal ecotype. Even if the number of arctic foxes has also been shown to vary on a local scale in Svalbard (Fuglei et al, 2003), the variation is far less than in inland tundra areas. The fox density in one area of Svalbard, in Adventdalen and Sassendalen (900 km 2 ), has been estimated to 0.1-0.15 animals per km 2 (Eide, 2002), considerably lower than in other arctic regions with arctic foxes of the inland ecotype.…”

“…Genetic studies show that a high gene flow, due to frequent long-distance foraging movements, has resulted in a panmitic circumpolar population of arctic foxes (Dalé n et al, 2005;Charmichael et al, 2007;Geffen et al, 2007) and that the occurrence of sea ice is likely the most important factor in explaining the genetic variation of Arctic fox populations in high Arctic islands (Geffen et al, 2007). The archipelago of Svalbard may be a closed entity for the arctic fox during summer but, during winter, these islands are normally surrounded by pack ice, enabling foxes to migrate between Svalbard and, for example, Novaja Semlja, Russia (Fuglei and Øritsland, 2003) or other Arctic tundra areas in Russia (Noré n et al, 2011). As is suggested for the introduction of the parasite Echinococcus multilocularis to Svalbard (Henttonen et al, 2001), it is likely that rabies was first introduced, and perhaps repeatedly reintroduced, through migration of foxes over sea ice (Prestrud et al, 1992;Johnson et al, 2007).…”

“…Coastal foxes living on islands or near the sea close to bird cliffs, in areas without lemmings, are dietary generalists, taking prey from both marine and terrestrial food webs; this provides a more-stable food supply and the foxes produce cubs every year, although relatively few. Arctic foxes in Svalbard belong to the coastal ecotype with a relatively stable population size (Fuglei et al, 2003). Due to the absence of small rodents, except for a very limited number of sibling voles (Microtus levis, formerly Microtus rossiaemeridionalis) in a restricted area, they prey mainly on migratory birds during summer and scavenge carcasses of reindeer and seals during winter (Frafjord, 1993;Eide et al, 2005).…”