p. 220 The tungara frog “after sunset, the males inflate their huge vocal sacs and force air through voice bosed larger than their brains. The esult is a short whine that falls in pitch, like a tiny, receding siren. After that, the male might add one ro more stort staccato embellishments that are known as chucks… female frog .. sit in front of various males, compare their whines and chucks, chose the most attractive-sounding specimen and allow him to fertilize her eggs…almost always for males who embellish their whines with chucks over males who merely whine. The chucks are so desirable that if a male is reluctant to make them, a female will sometimes body slam him until he does…. The frog’s inner ear is especially sensitive to frequencies of 2,130 Hz, which is just under the dominant frequency of the average chuck… They ought to chuck as frequently and repeatedly as possible, buty they’re strangely unwilling to do so…. The fringe-lipped bat turned out to be a voracious frog-eater. Turtle and Tyan showed that it tracks its prey by eavesdropping on its courtship calls, much as Ormia does with cricket songs. And the bat, just like the female tungara forgs, is particularly drawn to males that add chucks to their whines… The frog’s Umwelt shaped the frog’s calls, which then shaped the bat’s Umwelt. The senses dictate what animals find beautiful, and in doing so, they influence the form that beauty takes in the natural world.”
p. 233 “Although blue and fin whale songs can traverse oceans, no one knows if the whales actually communicate at such ranges. It’s possible that they’re signalling to nearby individuals with very loud calls … But Clark points out that they repeat the same notes, over and over again, and at very precise intervals. … It reminds him of the reperitive signals that Martian rovers use to beam dat back to Earth. If you wanted to design a signal that could be used to communicate across oceans, you’d come up with something These songs might have other uses, too. Their notes can last for several seconds, with wavelengths as long as a football field. Clark once asked a Navy friend what he could do with such a call. “I could illuminate the ocean,” the friend replied. That is, he could map distant underwater landscapes, from submerged mountains to the seafloor itself, by processing the echoes returning from the far distant infrasounds… Clark sees evidence in their movements… he has seen blue whales emerging in polar waters between Iceland and Greenaldn and making a beeling – a whalelines? – for tropical Bermuda, singing all the way. He has seen whales slaloming between underwater mountain ranges, zigging and zagging between landmarks hundreds of miles apart. “When you watch these animals move, it’s as if they have an acoustic map of the oceans,” he says. He also suspects that the animals can build up such maps over their long lives, accruing soundbased memories that lurk in their mind’s ear. After all, Clark recalls veteran sonar specialists telling him that different parts of the sea had their own distinctive sounds. “They said: If you put a pair of headphones on me, I can tell you if I’m near Labrador of off the Bay of Biscay,” says Clark. “I thought that if a human being could do this in 30 years, what could an animal do with 10 million years…. Underwater, ultrasound waves take just under a minute to cover 50 miles. If a whale hears the song of another whale from a distance of 1,500 miles, it’s really listening back in time by about half an hour, like an astronomer gazing upon ancient light of a distant star. If a whale is trying to sense a mountain 500 miles away, it has to somehow connect its own call with an echo that arrives 10 minutes later. That might seem preposterous, but consider that a blue whale’s heart beats around 30 times a minute at the surface, and can slow to just 2 beats a minute on a dive. They surely operate on very different timescales to we do.”
p. 239
“Mice, rats and many other rodents do indeed make a wide repertroire of ‘ultrasonic’ calls, with frequencies too high to be audible to humans. They make these sounds when playing or mating, when stressed or cold, when aggressive or submissive. Pups that are separated from their nests make ultrasonic isolation calls that summon their mothers. Rats that are tickled by humans make ultrasonic chirps that have been compared to laughter… Male mice that sniff female hormones produce ultrasonic songs that are remarkably similar to those of birds, complete with distinct syllables and phrases. Females attracted to these serenades join their chosen partners in an ultrasoci duet. Rodents are amont the most common and intensively studied mammls in the world and have been fixtures of laboratories since the 17th century. All that time, they’ve been spiritedly talking to each other without any human realizing.”
“Like infrasound, the term ultrasound is an anthropocentric affection. It refers to sound waves with frequencies higher than 20 kHz, which marks the upper limit of the average human ear. It seems special – ultra, even – because we can’t hear it. But the vast majority of mammals actually hear very well into that range, and its likely that the ancestors of our group did too. Even out closest relatives, chimpanzees, can hear close to 30kHz. A dog can hear 45 kHz, a cat 85, a mouse 100, and a bottlenose dolphin 150. For all of these creatures, ultrasound is just sound. Many scinetifists have suggested that ultrasound offers animals a private communication channel that others can’t eavesedrop on – the same claim that was made about ultraviolet light. We can’t hear these sounds, so we bill them as “hidden” and “secretive”, even though they’re patently audible to many other species.”
p. 246 1939 – discovered bat echo-location “One distinguished physiologist was so shocked by our presentation that he seized Bob [Galambhos] by the shoulders and shook him while expostulating ‘You can’t really mean that!’ … Even Griffin underestimated echolocation at first. He saw it merely as a warning system that alerted bats to possible collissions. But his views changed in the summer of 1951. Sitting by a pond near Ithaca, he began to record wild echolocating bats for the first time… When bats were crusing through open skies, their pulses were longer and duller. When they swooped after insects, the steady put-put-puts would quicken and fuse into a staccato buzz. Wasn’t just a collision detector. It’s also how bats hunt. “Our scientific imaginations had simply failed to consider, even speculatively, [this] possibility,” he later wrote.
p. 262 “The US Navy started training dolphins in the 1960s to rescue lost divers, find sunken equipment and detect buried mines. In the 1970s, it invested heavily in echolocation research, not to understand how the dophins themselves perceived the world but to improve military soar by reverse-engineering the animal’s suprerior capabilities… Dolphins could discriminate between different objects based on shape, size and material. They could distinguish between cylinders filled with water, alcohol and glycerine. They could identify distant targets from the information in a single sonar pulse. They could reliably find items buried under several feet of sediment, and they could tell if those objects were made of brass or steel – feats that no technological sonar can yet match. To date, “the only sonar that the Navy has that can detect buried mines in habors is a dolphin,” Au says … In 1987 Nachtigall’s team started working with a false killer whale – an 18-foot-long black-skinned dolphin species known for being smart and sociable. The animal, Klina, could use her sonar to tell the difference between hollow metal cylinders that looked identical to the human eye and that differed in thickness by the width of a hair. On one memorable occasion, the team tested Kina using two cylinders that had been manufactured to the same specifications. To everyone’s confusion, Kina repeatedly indicated that the objects were different. When the team had the cylinders remeasured, they realized that one had a miniscule taper and was 0.6mm wider at one end than the other. “It was incredible,” Nachtigall recalls. “We ordered them to be the same, the machinists said they were the same, and the animal said, “No, they’re different. And she was right.”
p. 296 “Although flowers are negatively charged, they grow into the positively charged air. Their very presence greatly strengthens the electric fields around them, and this effect is especially pronounced at points and edges, like leaf tips, petal rims, stigmas and anthers. Basded on its shape and size, every flower is surrounded by its own distinctive electric field. As Robert pondered these fields, “suddenly the question came: do bees know about this?… And the answer was yes.”
“Bumblebees…electroreceptors are the tiny hairs that make them so endearingly fuzzy. These hairs are sensitive to air currents and trigger nervous signals when they are deflected. But the electric fields around flowers are also strong enough to move them. Bees, though very different to electric fish or sharks, also seem to detect electric fields with an extended sense of touch … many insects, spiders and other artropods are coveed in touch-sensitive hairs. If these hairs can also be deflected by electric fields … then electric sense might be even more common on land than in the water.”
p. 307 As he showed in 1991, [sea] turtles have a compass. But their other magnetic sense proved to be even more improvessive. It hinges on two properties of the geomagnetic field. The first is inclination – the angle at which the geomagnetic field lines meet Earth’s surface. At the equator, those lines run parallel to the ground; at the magnetic poles, they are perpendicular. The second property is intensity – differences in the field’s strength. Both vary around the globe, and most spots in the ocean have a unique combination of the two. Together, they act like coordinates … allow the geomagnetic field to act as an oceanice map. And turtles, as Lohmann found, can read that map.”
p. 314 “Songbirds might be able to see Earth’s magnetic field, perhaps as a subtle visual cue that overlaps their normal field of vision. “That’s the most likely scenario, but we don’t know because we can’t ask the birds,” Mouritsen says.”
p. 332 “Controlling a human body is relatively simple for a human brain because our bones and joints constrain our movement. .. But… an octopus has “a body of pure possibility”. Aside from its hard beak, it is soft, malleable and free to contort. Its skin can change colour and texture on a whim. Its arms can extend, contract, bend, and rotate anywhere along their lengths, and have practically infinite ways of performing even simple movements. How could a brain, even a large one, keep track of such boundless options? The question turns out to be irrelevant. The brain doesn’ty have to. It can mostly let the arms sort themselves out, while imposing the occasional guiding nudge.”
p 339 In 1886, shortly after Edison commercialised the electric lightbulb, nearly 1,000 birds died after colliding with an electrically illuminated tower in Derateur, Illinois. Over a century later, environmental scientist Travis Longcote and his collagues calculated that almost 7 million birds a year die in the United States and Canada after flying into communication towers. The red lights of those towers are meant to warn aircraft pilots, but they also risrupt the orientation of nocturnal avian fliers, which then veer into wires or each other. Many of these deaths could be avoided simply by replacing steady lights with blinking ones.”
p. 344 “Noise pollution masks not only the sounds that animals deliberately make but also the “web of unintended sounds that ties communities together,” Fristrip tells me. He means the gentle rustles that tell owls where their prey are, or the faint flaps that warn mice about impending doom… Every extra 3 decibels can halve the range over which natural sounds can be heard. Noise shrinks an animal’s perceptual world. And while some species like great tits and nightingagles stay and make the best of it, others just leave. .. In noisy conditions, prairie dogs spend more tim underground. Owls flub their attacks. Parasitic Ormia flies struggle to find their cricket hosts. Sage grouse abandon their breeding sites (and those that stay are more stressed.”
p. 346 “Between World War II and 2008, the global shipping fleet more than tripled, and began moving 10 times more cargo at higher speeds. Together, they raised the level of low-frequency noise in the oceans by 32 times, a 15 decibel increase over levels that Hildebrand suspects were already around 15 decibels louder than in primordial pre-propeller seas. Since giant whales can live for a century or more, there are likely individuals alive today who have personally wirnessed this growing underwater racket and who now hear only over a tenth of their former range. As shops pass in the night, humpback whales stop singing, orcas stop foraging, and right whales become stressed. Crabs stop feeding, cuttlefish change colors, damselfigh are more easily caught.”
p. 348 In the woodlands of New Mexico, Clinton Francis and Catherine Ortega found that the Woodhouse scrub-jay would flee from the noise of compressors used in extracting natural gas. The scrub jay spreads the seeds of the pinyon pine tree, and single bird can bury between 3,000 and 4,000 pine seeds a year…in quiet areas where they still thrive, pine seedlings are four times more common than in noisy areas that they have abandoned. Pinyon pines are the foundation of the ecosystems around them – a single species that provides food and shelter for hunreds of others, including indigenous Americans. To lose three-quarters of them would be disastrous. And since they grow slowly, “noise might have 100-plus-year consequences for the entire ecosystem”.
About