The photo shown below was taken at a market in Shanghai, China.
Can you guess what they are?
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If you guessed, water caltrop 菱, you're right!
Water caltrops (Trapa natans) are the seeds of a floating annual aquatic plant that's native to warm temperate parts of Eurasia and Africa. The plant grows in slow-moving water up to 5 m deep, and bear an ornately shaped fruit that resembles the head of a bull or the silhouette of a flying bat. Each fruit contains a single very large, starchy seed. T. natans and T. bicornis have been cultivated in China and the Indian subcontinent for at least 3,000 years for the edible seeds that are used in pastries, served steamed or boiled from street vendors, and even as a remedy for inebriation.
A new study that's challenging the popular idea that we should drink eight glasses of water a day for health purposes shows that a 'swallowing inhibition' is activated by the brain after excess liquid is consumed. This inhibition mechanism helps maintain tightly calibrated volumes of water in the body.
The lead scientist has pointed out that if we just do what our body demands us to, we'll probably get it right. In other words, it is the best practice to just drink according to thirst rather than an elaborate schedule.
Building on a previous study, the researchers asked participants to rate the amount of effort required to swallow water under two conditions; following exercise when they were thirsty and later after they were persuaded to drin [ ... ]
Nothing, except for this fish, appropriately named the elephantnose fish (Gnathonemus petersii) for its peculiar, elongated spout. The fish is widespread in the flowing waters of West Africa and hunts insect larva at dawn and dusk. Its nose is actually a sensitive extension of its mouth, that it uses for self-defense, communication, navigation, and finding worms and insects to eat. This organ is covered in electroreceptors, as is much of the rest of its body. The elephantnose uses a weak electric field, which it generates with specialized cells called electrocytes, which evolved from muscle cells, to find food, to navigate in dark or turbid waters, and to find a mate. The elephantnose fish live to about 6 to 10 years. [ ... ]
To tap into scarce water supplies, most desert plants have extensive root systems that burrow deep or spread wide. But one desert moss has a different trick up its sleeve: a thirst-quenching structure called an awn. Awns are tiny, hairlike structures that project from the end of each leaf to capture water (above). For the first time, scientists have examined in detail how this moss (Syntrichia caninervis) pulls water right from the air using its awns. At the smallest scale, the awns are covered with grooves about 100 nanometers deep and 200 nanometers wide, the perfect size for dew to condense within them when conditions are right. Those nanogrooves lie within larger troughs that measure about 1.5 micrometers deep and 3 micrometers wide, a [ ... ]
The creature you see above is a spider that can actually surf on top of waves and hunt for a wide variety of animals including not only insects but also fish and toads. Dubbed the Dolomedes briangreenei, this species of spider floats on top of water and senses vibrations below to detect potential prey. The spider can even submerge itself underwater for up to an hour to hunt down prey, which makes it doubly frightening for any creatures caught in its path. The largest animals that the spider has been known to eat are cane toads, which can measure up to nine inches in length. For comparison, the D. briangreenei is about the size of a human palm. [ ... ]
Some bugs, such as water scorpions, long-toed water beetle and predaceous diving beetles (shown below) use the molecular properties of water to create miniature scuba diving tanks and spacesuits. The cohesive forces between water molecules essentially makes water molecules "stick" together, allowing bubbles to form against a wall of tension. These little insects are small enough to take advantage of this, by trapping a bubble in their outer wings or tiny bristles on their shell.
Shallow waters will sometimes get too hot, forcing one fish to make a break for the shore. The tiny mangrove rivulus (shown above) avoids neurological damage from hot swamps by escaping to land. Retreating to land allows the fish to cool down through a process called evaporative cooling, which is akin to human sweating but using water from the environment. Previously, scientists had suggested that the fish, besides simply escaping hot water, might be taking advantage of evaporative cooling.
Since its discovery in 2010, researchers have been trying to solve the mystery of dark streaks that appear and disappear seasonally on the planet's surface (shown above). Scientists are now claiming that this phenomenon, known as the recurring slope lineae, is caused by a bath of saltwater. What is still unknown, however, is where the water is coming from, or if the chemistry is even right for supporting life.
Meet the Irrawaddy dolphin (Orcaella brevirostris), a euryhaline species of oceanic dolphin found in discontinuous subpopulations near sea coasts and in estuaries and rivers in parts of the Bay of Bengal and Southeast Asia. Genetically, the Irrawaddy dolphin is closely related to the killer whale (orca). As evident in the collage, its forehead is high and rounded, and unlike most dolphins, the beak is lacking, giving it a you know what appearance - don't get any funny ideas now! [ ... ]
The shortfin mako (Isurus oxyrinchus) is probably the champion speedster among sharks. Its speed has been recorded at 40 km/h (25 mph) with bursts of up to 74 km/h (46 mph). What's more, this high-leaping fish can leap approximately 9 m (30 ft) high or higher in the air. With its highly streamlined body, a lunate tail supported by keels, a sharply pointed snout, large eyes and some of the wickedest-looking teeth in its class, the mako shark is a highly sought-after game fish worldwide.
Lost Lake, located in central Oregon, is known for rapidly draining every year through a six-foot (two-meter) wide hole in the lake's bottom (as shown in the video). Early in the following spring, however, the lake fills up again, as snowmelt from the surrounding mountains accumulates faster than water can drain out through the hole. That hole is really a lava tube - a geologic feature made when lava cools around the edges of a river of molten rock. After the hot lava drains away, it can leave an empty space. [ ... ]
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