How male water striders blackmail females into sex.
Water strider sex begins unceremoniously: the male mounts the female without any courtship rituals or foreplay. She may resist but if she does, he starts to actively strum the water surface with his legs. Each vibration risks attracting the attention of a hungry predator, like a fish or backswimmer(above). And because the female is underneath, she will bear the brunt of any assault.
The backswimmer menace is so potent that after a few minutes of tapping from the male, the female relents by opening her genital shield. If she had been previously attacked by predators, she gave in almost instantly. And only when she relented did the male stop his threatening taps.
In 1705, Emperor Peter I of Russia instituted a beard tax to modernize the society of Russia following European models. Those who paid the tax were required to carry a “beard token”. This was a copper or silver token with a Russian Eagle on one side and on the other, the lower part of a face with nose, mouth, whiskers, and beard. It was inscribed with two phrases: “The beard tax has been taken” and “The beard is a superfluous burden.” —Wikipedia
Many animals come together to find safety in numbers. In teeming herds, flocks, shoals and swarms, it’s harder for a predator to track and isolate any single individual. This is the standard view of animal groups, as espoused in countless nature documentaries. It rests on one big assumption—that the animals are in charge of their own behaviour. And that is not always true.
French scientists Nicolas Rode and Eva Lievens have found that two species of shrimp form swarms because they are being controlled by parasites in their bodies. Some of these need to get into birds to complete their life cycle. Others need to pass from one shrimp to another. They all achieve this by controlling their hosts and making them gather in large conspicuous swarms. The parasites can more easily jump into fresh hosts if the shrimps are swarming, and the swarms are more easily spotted and devoured by flamingos.
It’s a sinister twist on animal gatherings: Rather than finding safety in numbers, the shrimp are being collectively herded towards death’s door by unseen forces.
Rode and Lievens studied two species of brine shrimp—small crustaceans that looks like legs and eyes attached to a splinter. (You probably know them as sea monkeys.) Each one is just a centimetre long, but they gather in temporary swarms that can stretch for up to 2 metres. There are many possible explanations for these swarms, but none of them can fully explain what’s going on. The shrimp aren’t gathering in places rich in food or nutrients. They’re not avoiding predators, because they’ll still swarm in water that’s too salty to support fish. And while some species gather to mate, others reproduce by cloning themselves. Sex cannot be the only explanation.
“This video shows some fascinatingly odd animal behavior that I’ve never heard of before: baboons stealing stray puppies from their mothers and raising them as part of their troop. This kind of interspecies interaction where one species raises another species specifically for companionship and protection—in other words, keeping pets—is behavior that is typically attributed only to humans. To see it happening with baboons and dogs is nothing short of amazing.” - David Mizejewski
I was pretty shocked to find out just how little liquid fresh water Earth contains, like we saw in this post. But I was equally shocked to find out that as much as one-fifth of Earth’s fresh water is locked up in the beauty above: Lake Baikal.
Siberia’s Lake Baikal, not only the world’s oldest lake at ~25 million years of age, is the largest single fresh water source on the planet. The water is so deep and so pure that when it freezes it becomes a sort of cold, turquoise glass, giving an observer a lens that can see over 100 feet straight down.
“But there is a marvellous thing related of this Desert, which is that when travellers are on the move by night, and one of them chances to lag behind or to fall asleep or the like, when he tries to gain his company again he will hear spirits talking, and will suppose them to be his comrades. Sometimes the spirits will call him by name; and thus shall a traveller ofttimes be led astray so that he never finds his party. And in this way many have perished. [Sometimes the stray travellers will hear as it were the tramp and hum of a great cavalcade of people away from the real line of road, and taking this to be their own company they will follow the sound; and when day breaks they find that a cheat has been put on them and that they are in an ill plight. Even in the day-time one hears those spirits talking. And sometimes you shall hear the sound of a variety of musical instruments, and still more commonly the sound of drums.”
From science-junkie: Travellers in the desert have long known that shifting sand can make an eerie noise, ranging from a bass boom to a baritone bark and a soprano whistle. The sound occurs when the ridge of a sand dune builds up and eventually topples. This shear effect causes a mini-avalanche of sand in which millions of grains rub against each other as they fall. But different materials and different conditions make different songs.
Lab experiments show that synchronicity plays a vital role. Put simply, enough grains have to be flowing at the same rate in order to create and amplify the oscillation. In turn, the factors behind synchronicity are wind speed, humidity, the size of the sand grain and the smoothness of its coating, too.
Much of the scientific fascination surrounding booming dunes stems from the fact that their properties are so hard to pin down. Booming doesn’t occur on all desert dunes. And on those that do boom, the phenomenon doesn’t occur throughout the entire year or everywhere across the dune. The frequency can vary too – from roughly 65 to 120 Hertz – while the volume can reach 110 decibels — just 20 dB short of the pain threshold.
Sources: [x] [x] [x] Image: [x] Audio: Physicist Simon Dagois-Bohy and his fellow researchers at Paris Diderot University in France recorded two different dunes: one near Al-Askharah, a coastal town in southeastern Oman, and one near Tarfaya, a port town in southwestern Morocco..
Now as your mouth hangs open I don’t want to ruin your day by dropping a truth-turd in there, but it’s worth remembering, as commenter sean14powell says “that the camera has a specific frame rate, in this case close to 24hz. In reality this water looks like a fanned spray. The hose is flexing back and forth and the camera is always capturing it at the same time so it ‘freezes’ in shape. If the speaker is slightly faster then the camera the water appears to flow in reverse but really the water is flowing forward at 98% of the camera speed. Think movies of tires or helicopter blades that freeze or move backwards.