Fur and Feathers Get Grip on Ice

Biological Strategy

Seals

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Image: Thomas Lipke / Unsplash / Free non-commercial use

Move in/on Solids

To obtain needed resources or escape predators, some living systems must move on solid substances, some must move within them, and others must do both. Solids vary in their form; they can be soft or porous like leaves, sand, skin, and snow, or hard like rock, ice, or tree bark. Movement can involve a whole living system, such as an ostrich running across the ground or an earthworm burrowing through the soil. It can also involve just part of a living system, such as a mosquito poking its mouthparts into skin. Solids vary in smoothness, stickiness, moisture content, density, etc, each of which presents different challenges. As a result, living systems have adaptations to meet one, and sometimes multiple, challenges. For example, some insects must be able to hold onto both rough and slippery leaf surfaces due to the diversity in their environment.

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Modify Position

Many resources that living systems require for survival and reproduction constantly change in quantity, quality, and location. The same is true of the threats that face living systems. As a result, living systems have strategies to maintain access to shifting resources and to avoid changing threats by adjusting their location or orientation. Some living systems modify their position by moving from one location to another. For those that can’t change location, such as trees, they modify position by shifting in place. An example of an organism that does both is the chameleon. This creature can move from place to place to find food or escape predators. But it also can stay in one place and rotate its eyes to provide a 360-degree view so that it can hunt without frightening its prey.

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Mammals

Class Mammalia (“breast”): Bats, cats, whales, horses, humans

Mammals make up less than 1% of all animals on earth, but they include some of the most well-known species. We know first-hand some of the characteristics that make mammals unique, like having hair, being able to sweat, and producing milk through mammary glands. Another critical shared feature is a set of highly-specialized teeth. Unlike sharks or alligators, for example, whose teeth are generally all the same size and shape, mammals have differently shaped teeth in different areas of the jaws to target specific foods or foraging strategies.

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Fur and feathers of seals and penguins help them get a grip to climb ice floes and snow thanks to their stiffness.

Image: Glenn Grant, National Science Foundation / Wikimedia commons /

A Emperor Penguin dives into the water somewhere in Antarctica. Emperor Penguins can dive as deep as 550 meters, with 20 minutes of air in a single breath.

Image: Wikimedia commons /

Southern Elephant Seal (Mirounga leonina) (young) in South Georgia.

“For the seals of the icy seas and the penguins of the antarctic shore this gliding and braking mechanism is vital. When they leave the water to climb an ice floe, they get a grip with their stiff fur or feathers. They can scale 60° inclines in this manner. When they rush back into the water, they simply slide down on their stomachs. Numerous other animals that live in the snow have bristles on their running or creeping surfaces, for the same mechanical reasons.” (Tributsch 1984:73)

Last Updated September 14, 2016

References

Book

How Life Learned to Live: Adaptation in Nature

The MIT Press | 01/01/1983 | Helmut Tributsch

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