Hippos spend 16 hours a day submerged in water. Withough Sun protection, they wouldn’t survive.

That reddish substance that sometimes appears on the skin of hippopotamuses?

That unique secretion serves as a sunscreen, protecting them from solar radiation. The secretion contains two highly acidic and unstable compounds: hipposudoric acid (red) and norhipposudoric acid (orange).

When these compounds mix with mucus and dry on the hippo’s skin, they form a durable layer that acts as a natural sunscreen, protecting the animal from harmful UV rays for hours. Hippos are semiaquatic, spending up to 16 hours a day submerged in water to stay cool, but this does not shield their skin from the sun, making their natural sunscreen essential.

Scientists believe the secretion is synthesized from amino acids when exposed to oxygen, though much about its exact mechanisms remains unknown. Recent research has revealed that the secretion, often referred to as “hippo sweat,” contains microscopic structures that scatter light, providing both sunblock and sunscreen properties. The substance also includes red and orange pigments capable of absorbing ultraviolet light, contributing to its effectiveness.

A 46,000-year-old worm frozen in Siberian permafrost has been brought back to life, revealing new insights into survival in extreme conditions.

The rules of immunity.

Spider webs aid arachnids in hearing, a principle that could enhance microphone technology.

---

A study reveals how spiders use their webs to detect sound velocity, leading to the development of a microphone with enhanced sensitivity.

Frozen in time for 24,000 years—then suddenly alive again. Scientists have revived ancient microscopic creatures from Siberian permafrost, revealing an extraordinary survival trick that could revolutionize cryobiology. What secrets do these tiny survivors hold?

Synthetic aperture radar (SAR) is an important tool for observing the oceanic internal wave phenomenon. However, owing to the unstable imaging quality of SAR on oceanic internal waves, the texture details of internal wave images are usually unclear, which is not conducive to the subsequent applications of the images. To cope with this problem, a texture enhancement method for oceanic internal wave SAR images is proposed in this paper, which is based on non-local mean (NLM) filtering and texture layer enhancement (TLE). Since the strong speckle noise commonly present in internal wave images is simultaneously enhanced during texture enhancement, resulting in degraded image quality, NLM filtering is first performed to suppress speckle noise.

Although rock glaciers (RGs) are prevalent in the southwestern Pamirs, systematic studies on them are scarce. This article introduces the first inventory of RGs in the southwestern Pamirs, situated at the western edge of the High Mountain Asia region. The inventory, established through a combination of Google Earth optical imagery and Interferometric Synthetic Aperture Radar (InSAR) techniques, encompasses details on the locations, geomorphological parameters, and kinematic attributes of RGs. A total of 275 RGs were cataloged in an area of 55.52 km2 from 3,620 to 5,210 m in altitude. Our inventory shows that most RGs in this region are talus-connected (213 landforms), with the highest frequency facing northeast (23%). The distribution of RGs thins from west to east and is more abundant in higher altitudes.

How could I expect a source code release by my own forces?