Why do animals survive first

Animal strategies against cold: the 7 best model experiments

Why don't duck feet freeze on ice?

Although ducks have a body temperature of around 40 ┬░ C even in winter, their feet are icy cold. Cold feet have two decisive advantages for them. On the one hand, they cause little heat to be lost to the cold floor. On the other hand, the ducks do not run the risk of thawing the ice on the duck pond and thus freezing under certain circumstances. The enormous temperature gradient from the warm core of the body to the icy feet is maintained by a countercurrent heat exchange. The warm-blooded arteries from the body are very close to the cold-blooded veins from the feet. Due to the proximity, the venous blood is always warmed up on the way to the center of the body and the arterial blood is cooled on the way to the feet. This heat exchange principle can easily be demonstrated in the school laboratory with copper pipes and jam jars.

Short or long? Big or small - what is better for cold zones?

With a large body surface, a lot of heat is lost. According to Allen's rule, the appendages of many species in the polar regions are therefore shorter than those of their relatives in warmer climates. This can be seen, for example, in the comparison of the ears of snow hare, field hare and donkey hare. The loss of heat from a large body surface can also be put into perspective by an enormous body volume. This is reflected in Bergmann's rule. The emperor penguins in the Antarctic are much larger than their smaller relatives on the Galápagos Islands. These differences between the species show a clear adaptation to the habitat. Schoolchildren can research it themselves using a disposable glove and a jam jar.

Why do polar bears have dark skin?

Long, thick fur, small ears and a large body - polar bears use several strategies to protect them from heat loss. Her black skin color also supports her in this. The dark color best absorbs the thermal energy of the sun's rays, which also warms the polar bear. In this example, students learn that chocolate kisses are not only delicious, but can also be used experimentally.

Exact descriptions and instructions for the model experiments presented here can be found in our booklet "Learning through research: Low Cost".

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