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Nocturnal Animals: When Stars Guide the Way

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Have you ever wondered what would happen if you got lost in the desert? What if you have nothing to light up the dark except for groups of stars dispersed in the night sky? Well, that will not be a problem if you were a dung beetle, a bird, or even a seal. Getting lost in the desert could be fatal for those who do not have navigation mechanisms—the ability to find the way accurately without maps or instruments. How exactly can stars help some creatures find their way through the dark?

Nocturnal Magic

Nocturnal animals are those who become active at night for several reasons; migrating, hunting, mating, or foraging. They take night as a way of protection from predators, the burning Sun, or other elements threatening their safety. That is when all the magic happens.

Based on a study from Lund University in Sweden, nocturnal animals follow groups of stars and observe individual stars to guide their way. This ability is not as easy as it seems, it is actually very complicated and requires a more thorough investigation. It is worth mentioning that each species has its own way of navigation. For example, some animal species along with humans have camera eyes that make them navigate similarly and observe individual stars. On the other hand, insects have compound eyes that help them navigate using a completely different method.

Avian GPS

Birds’ migration is always taken for granted; yet, it is an impressive and quite intelligent procedure. While some birds use Earth’s magnetic field to navigate, others are guided by the Moon and the sky to show them the way. Scientists concluded that birds identify the starry sky’s center of rotation during their orientation process. This orientation strategy could be used at any hour of any night.

Wildly-caught birds were brought to the Longway Planetarium to study their orientation strategies. The experiment revealed some very interesting information; for indigo buntings, it does not really matter whether or not they can see individual stars, as they are more concerned with seeing the rotation of close star patterns around a center point. In the wild, this enables them to detect the direction of north, and they use that piece of information to head south for their winter migration.

Milky Way Orientation

Surprisingly, scientists discovered that, not only animals and birds can navigate, but these abilities also exist in insects. As previously mentioned, insects, such as dung beetles, have compound eyes. This means they cannot observe individual stars, as their eyes are too small to see them; instead, they navigate using the light that comes from the Milky Way to know the correct direction, making them the only insects known to orient by the galaxy. Not only that, dung beetle’s ability to navigate using polarization patterns in moonlight, makes it the first animal known to use this method for orientation. What makes all this truly incredible is that this dung beetle is a very small creature with a brain the size of a grain of rice; yet, it has an impressive ability that most of us dream of having.

Hidden Navigational Intelligence

The story of harbor seals, these friendly marine mammals, does not stop at being cute and funny, there is so much more! As they consume much of their time foraging for food at night without terrestrial landmarks, an experiment had to be conducted to investigate the seals’ navigational abilities. In 2006, two captive seals from the Marine Science Center in Germany were placed in a floating planetarium, specifically constructed for them. The two pinnipeds, Nick and Matte, were trained to swim in specific lodestars’ direction. It was then discovered that both of them were able to identify a single star out of a realistic projection of the Northern Hemisphere night sky. These results indicate that seals might use specific lodestars as navigational cues to walk far from shore; this makes it the first scientific evidence of a marine mammal orienting by the stars.

The Maori

Once upon a time, humans could navigate too! A primitive tribe from eastern Polynesia, named the Maori, arrived at New Zealand between the years 1280–1300. They did not carry any instruments or tables to consult; instead, they depended completely on the sky as their guide. Their navigational process relied on observing the night sky, local weather patterns, and ocean currents, to reach their destination.

Fascinating! In the time of GPS, maps, and navigational technology, it is almost impossible to see a human being naturally navigating. Does it mean that we can no longer navigate on our own as animals do? Actually, we can; just like any other skill, navigation needs practice. We were born with a navigational instinct; however, due to the technological development, we stopped using our stellar orientation skills gradually until we no longer know how to do that.

Some passionate navigators take time to teach others how to do a tech-free navigation, based on their experience. If you are also passionate and want to reach your deepest hidden instincts, take a look at this article. You can also read The Natural Navigator book for additional knowledge on this interesting topic.

References

nationalgeographic.com
ncbi.nlm.nih.gov
sci-news.com/biology
sci-news.com/nocturnal-animals
space.com


The original article was published in SCIplanet, Spring 2020 issue "Dualities of Life: The Earth and The Sky".

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