Adaptations to Altitudes
As a species that can survive in the 5000 meters mountain, snow leopards have evolved several physiological and morphological adaptations to the high altitude. To insulate themselves from the freezing wind and cold weather, the snow leopards have the densest pelage among all the big cat species, which has around four thousands fur per square centimeters. Around each fur, there are approximately eight underfur surrounding it.(Heptner, 1989). In the winter, the snow leopards fur is almost twice as dense in the summer(Figure 11)(Hemmer, 1972).
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Figure11. Hemmer, Helmut. "Uncia uncia." Mammalian Species 20 (1972): 1-5.
The snow leopard’s have relatively large paws, which are around 10% of their body sizes. The furry paws act like natural “snow shoes” of the snow leopards, keeping them balanced and insulated walking in the snow(National Geographic, 2015). What’s more, snow leopards also have unique respiratory systems for the cold airs and low oxygen levels in the high altitude. First of all, the snow leopards have large nasal cavities, which can help them inhale as much as oxygen from the thin air. Besides this, the nasal cavities contain turbinates, which are composed of bones and tissues(Figure 12). The turbinates are able to warm up the inhaled freezing air with the exhaled warm air before the inhaled one reaches the lungs tissues(National Geographic, 2015).
Because of the scarcity of snow leopard, the research about their genome that contribute to their ability to tolerate hypoxia in high altitude has been limited. In a recent study examining the genome of the snow leopard related mammalian species examined, snow leopards’ genomes have special amino-acid changes in both EGLN1 and EPAS1 genes(Cho et al, 2013)(Figure 13). Previously, those two genes have been examined to be related to the high altitudes adaptations in human from other study(Xu et al, 2011). What’s more, naked mole rats are also capable of tolerating hypoxia, and in the genome examination, the naked mole rats show unique amino acid changes in the EGLN1 genes, which further confirm the possibilities that the unique amino acid sequence on the EGLN1 genes that snow leopard have may contribute to their ability to survive under the low oxygen environment(Cho et al, 2013).
Figure12. See how the elusive snow leopard is adapted to one of Earth's most extreme environs. (2020, June 17). Retrieved December 20, 2020, from https://www.nationalgeographic.com/magazine/2020/07/see-how-the-elusive-snow-leopard-is-adapted-to-one-of-earths-most-extreme-environs-feature/
Figure 13. EGLN1 and TYR mutations related to hypoxia in snow leopard and white fur in white lion. Cho, Y. S., Hu, L., Hou, H., Lee, H., Xu, J., Kwon, S., ... & Shin, Y. A. (2013). The tiger genome and comparative analysis with lion and snow leopard genomes. Nature communications, 4, 2433.