Week Six: morphology specialisation for terestrial animals to survive in different tertiary environments: Part 2: Cold & Hot.

Viewed 13/4/17: https://www.youtube.com/watch?v=Bx2lWo-_fO8

This week’s blog is on the morphology specialisations of some terrestrial animals living in extreme hot or cold environments. I’ll talk about what some of the changes are that have become evident within these populations of animals. These changes are not purely exclusive to morphology, however I’ll be covering what some of the more obvious changes that have become evident are.

Firstly cold environments, they can be extremely cold, this can make persisting in these environments difficult so why live there? The Arctic and Antarctic are the coldest places in the world. Alternatively deserts are some of the hottest, this makes maintenance of a constant body temperature hard to regulate and requires some balancing between heat generation and dissipation for both types of extreme climate, this can be energetically more costly for these animals. A way this can be seen is in the adaptation of thickened furs and different skin insulations/ colours for addition forms of warmth or cooling (Scholander, et al, 1950).

This can be seen in the polar bear (Ursus maritimus) (Figure 1) who can be found mostly in the Arctic Circle, and has adapted to life on ice by occupying the available ecological niche. They mostly feed on seals in order to keep their adipose (fat) stores high, which are used to maintain a four inch thick layer under the skin surface which is utilised for addition warmth in conjunction with a thickened fur coat (Durocher, 2004). Some other notable features of polar bear morphology include; the minimalized ear surface area to avoid excess cold to the area, extended claws for ripping while feeding, and larger paws for a widened surface area of contact for increased stability while walking on snow and sheet ice.

Figure 1. Polar bear (Ursus maritimus)

Viewed 13/4/17: http://bit.ly/2oq5Egz

Some animals have adapted to a life in excessively hot desert climates, in order to do so, some phenotypic/morphological changes have been utilised to increase survival. A prime example is the Fennec Fox (Vulpes zerda), which is largely recognised for its larger ears (Figure 2). This larger size has been adapted for the use of heat dissipation through the larger surface area. In addition to this the Fennec Fox is largely nocturnal and has developed a creamy coloured fur phenotype to reflect sunlight for during the day and to keep the fox warm at night (Carlstead, 1991).

Figure 2. Fennec Fox (Vulpes zerda)

Viewed 13/4/17: http://bit.ly/2oBqUCf

References:

Carlstead, K. 1991, Husbandry of the Fennec fox: Fennecus zerda: environmental conditions influencing stereotypic behaviour, International Zoo Yearbook, Vol 30, Issue 1, pp 202-207

Derocher, A. Lunn, N. Stirling, I. 2004. Polar Bears in a Warming Climate, Integrative and Comparative Biology, Vol 44, Issue 2, pp 163-176

Scholander, P. Hock, R. Walters, V. Irving, L. 1950, Adaptation to cold in Arctic Mammals and Birds in Relation to Body Temperature, Insulation, and Basal Metabolic Rate, The Biological Bulletin, Vol 99, Issue 2.