Eternal Youth
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“The Fountain of Youth,” Lucas Cranach the Elder, 1546. Gemäldegalerie, Berlin (Wikimedia Commons; public domain)
Nature

Eternal Youth

How Non-Humans Age
Adam Zbyryt
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time 10 minutes

Although it’s long been suspected that some turtles, fish, trees, and marine invertebrates do not age, it was always assumed that they are the proverbial exceptions confirming the rule. Now it is known that “forever young” species are as common as those that do age.

Imagine someone that never gets old. The first person that comes to mind might be Connor MacLeod from the Highlander movie series, or the vampire Lestat from Anne Rice’s Interview with the Vampire. And yet it turns out that exceptionally long-lived organisms do really exist. They live on Earth, alongside humans, and often closer than one would expect.

They join us, for example, in the lakes we swim in during summer vacation—and can even be seen with the naked eye, without the need for a lab microscope. Hydra vulgaris, or the fresh-water polyp, can grow up to 2.7 inches in length. Although it’s an animal, the hydra resembles a plant—it looks a bit like a tree trunk, and its tentacles resemble branches. The roots seem to be missing, but the hydra is able to cling to a given base object and stay there for years, which is also more typical of plants than animals. Still, its appearance and behavior shouldn’t deceive anyone—it is actually a voracious and effective predator that feeds on both zooplankton and small fish.

The most remarkable feature of Hydra vulgaris isn’t its appearance or diet, but the fact that it does not age. What is more, if it loses part of its body, it can rapidly heal and regenerate: like a phoenix from the

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The Forest Broadcast
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Photo by T La/Unsplash
Nature

The Forest Broadcast

Birdsong in Spring
Adam Zbyryt

What do the seasons sound like to a naturalist’s ears? Each one sounds different, and spring – a time of avian and batrachian cacophony – has got the nicest sound of all. Winter and summer are not completely devoid of pleasant tones, but it’s in May that true ecstasy can be found.

In the spring, the sounds of nature can be heard everywhere: in fields, forests, meadows and among reeds; in wastelands, woodlands, shrublands, city parks and home gardens. They come from overhead – as flocks of winged wanderers big and small sweep across the sky on their way back from their winter habitats – and from the surface of the water, where birds land to rest or eat.

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