Saiga tatarica Saiga Mammals were the first fossil animals to be found in the caves of Southeast Alaska, and they have provided the bulk of the information about ancient environments. This is in part because of their limited mobility among the islands compared to birds and fishes. Large mammals appear to be able to colonize islands fairly quickly once suitable habitats become available, whereas small mammals have great difficulty.
The table at the left lists all mammal species that have been found thus far of all ages from the caves of Southeast Alaska. Some species have only been recovered from island caves, whereas others have only been found in caves on the mainland.
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Prior to our work, if was generally believed by geologists and biologists that Southeast Alaska was rendered uninhabitable during the Ice Age, and that all animals in the region are postglacial immigrants. This was well-stated in the last biological study of the region prior to the s by Dr. Klein in : During the Wisconsin glaciation the present land areas of the coastal regions of Alaska bordering the Gulf of Alaska were virtually completely overridden by ice.
The now existing flora and fauna of the region have presumably become established in the 10, years since the recession of the ice. The present distribution of mammals in this region, although complicated by the phenomenon https://tikoev.site/tag5/6065.php insularity, reflects the sequence of their arrival and their relationship to specific refugia.
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Klein hoped to explain the curious distribution of bears in the Alexander Archipelago. Only brown bears live on islands north of Frederick Sound i. Admiralty, Baranof, and Chichagof Islandswhereas only black bears inhabit islands south of Frederick Sound Prince of Wales and surrounding islands.
This made sense in terms of postglacial colonization since brown bears came from Asia and black bears came from North America.
Klein continued: The presence of the brown bear on all large islands northwest of Frederick Sound including Kodiak Island and the islands of Prince William Sound suggests that this bear had access to these areas in a very early postglacial period, possibly before the sea level had risen substantially and prior to the arrival of the black bear and most ungulates. The present lack of movement of brown bears across the water channels separating these islands also supports the thesis that these bears reached the islands when access was easier than at present.
Possibly access to the northern islands of the Alexander Archipelago was via the coastal dating of fossils red notes from the Prince William Sound region. The failure of brown bears to occupy the islands south of Frederick Sound when access became available may be a result of prior occupancy by the black bear.
A previously established species obviously has an advantage over a similar form attempting to occupy the same ecological niche.
Without a historical record, the present lack of brown bears on Prince of Wales Island was more info attributed to competition and an inability of this species to colonize the island at the end of the Ice Age.
But the premise that brown bears never inhabited Prince of Wales and dating of fossils red notes southern islands was proven incorrect by the discovery of a fossil record. The bear skeletons found in El Capitan Cave in included both black and brown bears, and more brown bear remains were soon found in Blowing in the Wind and Bumper caves. Since that time, brown bear remains have also been found in caves on Dall and Coronation Islands.
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This means that brown bears have a long history in the southern Alexander Archipelago, and they may have have even survived there during the Last Glacial Maximum rather than being postglacial immigrants. The caribou antler at left was found in On Your Knees Cave. Several other species were found in early postglacial cave deposits of Prince of Wales Island that do not live on the island today.
A red fox lower jaw and upper canine photo below and a fragment of a wolverine molar were found in El Capitan Cave. A caribou fragment was found in Bumper Cave.
An arctic fox skeleton photo below and more bones of red fox and caribou were found at On Your Knees Cave. These discoveries, like that of brown bear, suggested that the Prince of Wales Island mammal fauna was not simply the result of postglacial colonization else why did so many immigrants quickly die out. This was further confirmed by the older record at On Your Knees Cave.
Arctic fox and red fox were recovered that dated to the glacial maximum and to the preceding time interval for arctic foxso they were survivors from the Click Age. Brown bear, black bear, and caribou were found that dated to before, as well as after, the glacial maximum, but it is still unclear whether they survived the glacial maximum on coastal refugia or merely recolonized the islands afterward.
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In the case of brown bear, a genetic study of modern populations suggests that a population was isolated in Southeast Alaska during the Last Glacial Maximum. Arctic fox upper jaw and skeleton at right was https://tikoev.site/tag19/7359.php important bone accumulator at On Your Knees Cave. Red fox lower jaw, El Capitan Cave was also present.
One of the most surprising discoveries at On Your Knees Cave was bones.