According to the 2014 Arctic Report Card, there have been significant changes in sea ice extent. Specifically, the report addresses the slow but significant seasonal decline in sea ice cover. Arctic sea ice is of utmost importance for ecosystems to thrive. Post et al. (2013) discuss this further, stating “the sea-ice biome influences the abundance, distribution, seasonality, and interactions of marine and terrestrial species.” This is especially true for polar bear populations in the Arctic, as the presence of sea ice is imperative to their survival. Increased alterations in seasonal sea ice retreat and return influence movement patterns, predation, and mating (Derocher & Sahanatien, 2012). Earlier sea ice melt means polar bears must retreat
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Polar bears have recently been observed to attack prey in uncharacteristic ways. There have also been observed cases of both cannibalism between polar bears, and hybridization with grizzly bears in terrestrial habitats. These are directly related to seasonal changes in sea ice …show more content…
They will wait until a seal swims up, and will make an attack. Although seals will keep these holes open throughout the winter, “loss of ice limits their distribution” (Polar Bears International, 2015). Unusually low numbers of seals cause polar bears to act out on their hunger. As a result, the bears have been observed clawing through solid ice in an attempt to catch the seals, which “is a significant departure from normal and documented patterns of hunting behaviour” (Stirling et al., 2008). The bears were digging through the ice to access open lairs. Bromaghin et al. (2015) observed similar instances, citing “several instances of polar bears penetrating unusually thick ice barriers to reach ringed seal lairs … predatory behavior that is energetically inefficient and a likely indication of nutritional stress.” This same food stress has led different populations in other regions to act in other uncharacteristic ways. Although polar bears are not described to be territorial or aggressive towards each other, there have been instances of cannibalism in certain populations. In a paper by Stirling and Ross (2011), they reported that “most observations of intraspecific predation and cannibalism by polar bears outside the breeding season have been made on land in late summer or autumn.” This correlates with ice-break up and ice-freeze up seasons, and could possibly be related to the sea ice
Polar bears have recently been observed to attack prey in uncharacteristic ways. There have also been observed cases of both cannibalism between polar bears, and hybridization with grizzly bears in terrestrial habitats. These are directly related to seasonal changes in sea ice …show more content…
They will wait until a seal swims up, and will make an attack. Although seals will keep these holes open throughout the winter, “loss of ice limits their distribution” (Polar Bears International, 2015). Unusually low numbers of seals cause polar bears to act out on their hunger. As a result, the bears have been observed clawing through solid ice in an attempt to catch the seals, which “is a significant departure from normal and documented patterns of hunting behaviour” (Stirling et al., 2008). The bears were digging through the ice to access open lairs. Bromaghin et al. (2015) observed similar instances, citing “several instances of polar bears penetrating unusually thick ice barriers to reach ringed seal lairs … predatory behavior that is energetically inefficient and a likely indication of nutritional stress.” This same food stress has led different populations in other regions to act in other uncharacteristic ways. Although polar bears are not described to be territorial or aggressive towards each other, there have been instances of cannibalism in certain populations. In a paper by Stirling and Ross (2011), they reported that “most observations of intraspecific predation and cannibalism by polar bears outside the breeding season have been made on land in late summer or autumn.” This correlates with ice-break up and ice-freeze up seasons, and could possibly be related to the sea ice