Eavesdropping on pink river dolphins could help save them
Particular creatures have adapted to live by sound without light or in a place where sight isn’t a factor. They rely on the sounds of calls, tweets, clicks, and clicks to make a map of the surroundings or identify the prey. This ability is known as echolocation, and an easy method to comprehend the mechanism behind it is to break down the word.
Is echolocation a real thing?
Consider the sound of an Echo that detects things. The sound hits the object and bounces back, transmitting information about the target’s location or providing navigation cues. In 1944, when Harvard University zoologist Donald Griffin created the term “echolocation” in Science 1944, he described bats’ reliance on sound for navigation as “fly through the total darkness of caves without striking the walls or the jutting stalactites.”
Since then, scientists have discovered many other animals that utilize echolocation, also known as biosonar. For instance, at least 16 species of birds echolocate, such as swiftlets and nocturnal oils birds, who roost in the caves of South America. Laura Kloepper, an expert in animal acoustics from the University of New Hampshire, describes this ability as an instance of convergent evolution where “you have two unrelated species evolve the same adaptive strategy.”
What is the function of echolocation?
To spot fish in deep waters or to stay clear of crashing into the night, whales and bats make intense ultrasonic sounds with high frequencies of up to 200 Kilohertz. This is far beyond human hearing (most adults can’t hear pitches that exceed 17 Kilohertz).
What is the reason that echolocators with specialization employ ultrasonic sound? “High-frequency sounds give excellent spatial resolution,” Kloepper clarifies. Hertz refers to the distance between the acoustic waves. The higher the hertz, the more influential the sound, and the lesser the details captured by the energy oscillation within the air. When you echolocate within the room, a large low-frequency sound could reflect off the walls, Kloepper says, while echos from higher frequency sounds can tell you the location of the doorway or even the knob.
Echoes can be a wealth of information, provided you know how to interpret them. According to Kloepper, when an animal can hear reflections, it compares the sound to an “internalized template” of the message it was sent. The comparison of echo and signal can reveal the distance from a target and the direction it may be moving within or even its physical makeup.
Ultrasonic sounds give bats another extra boost. They depend on the next level of frequencies to locate partners. A variety of moth species hunted by bats have developed ears that are tuned to these frequencies as a way to survive.
What animals are using echolocation?
Of the critters that can detect echolocation, bats, toothed whales, bats, and dolphins are among the top performers. Dolphins can identify objects more significant than 300 yards away and notice whether the target is surrounded by fluid. Bats’ range peaks at about a dozen yards; however, they can see objects as they move through dense forests or in a massive bat crowd. Using sound, both mammals can see differences in the location of things as small as a fraction of an inch. Different animals are equipped with their version of sonar and customized to their particular capabilities and preferences.
Fossils suggest that bats were guided by sound for at most 52 million years, which is more than when humans were around. Hundreds of species within the mammalian family can echolocate, which they employ to hunt down moths and mosquitoes as well as other predators. Certain insectivorous bats are skilled at this; they can detect motionless insects in leaves in the darkness of the dark. In response, various insects have developed defenses against bat sonar, a battle with bat sonar that biologists have described as an arms race. Luna moths produce long tails that could serve as decoys that reflect light, confusing bats. Others emit ultrasonic signals in their way to block the enemy’s sonar.
To produce an ultrasound sound, a bat shakes an organ that is specialized in its throat, known as the larynx. It’s similar to how the human voice box functions, but the bat makes more high-frequency sounds. Certain species of bat release the sound out of their mouths. Others make a screech out of their snouts, using a complex nasal structure dubbed a nose leaf.
Orcas, dolphins, and other whales with teeth echolocate for the same reason as bats do: search for tasty prey and navigate through the darkness. However, these aquatic animals emit ultrasounds differently. The whale’s head, usually close to its blowholes, has flaps resembling lips. When animals press air against the flaps, their appendages vibrate, generating clicks. “It’s exactly like when you fill a balloon with air and let the entire air out. It creates the sound of a PBBFFnoise,” Kloepper says.
The contours of the dolphin’s skulls make the sound into fat structures in the front of their head, known as melons. They, in turn, effectively transmit sound waves in seawater. Waves bounce off objects such as prey or other animals; however, whales don’t depend on external ears to pick up the echo (their ears are filled with wax). Instead, the sound waves are channeled through their jawbones, and sound is picked up by the fat-filled cavities, which are so thin that they can absorb light. The holes are situated near the whale’s ears, which detect the sound waves that echo. This process can reveal all kinds of information, including where a fish is, where it’s heading, and the speed at which it’s swimming.
Shrews are sensitive to whiskers, but they have poor eyesight. To aid their senses as they move through their meadows and forest environments, they may employ an echolocation technique that, course Sophie von Merten Mammalogist at the University of Lisbon in Portugal, calls “echo-orientation” or “echo-navigation.” This ability may “give them a hint that there is an obstacle coming,” she states, for example, falling branches which are recognized by the shrews’ tweets. Their bird-like noises are faint. However, they are audible to humans.
The degree of echo navigation by shrews isn’t fully understood. In 2020, in an “experiment, von Merten and another researcher found that when shrews were introduced to unfamiliar environments and environments, the animals tweeted more often. Von Merten says they’re likely sensing the unfamiliar area through these vocalizations. However, another possibility is that the animals in captivity are under stress. This is a theory she finds to be unsubstantial, although her ongoing studies will be able to measure pressure in shrews, as well.
Soft-furred tree mice
In 2021, research published in The journal Science discovered the existence of four varieties of soft-furred tree mice that echolocates by squeaks. The rodents belong to the Genus Typhlomys, which means “blind mouse,” and live in thick bamboo forests of China in China and Vietnam. Analyzing the animal’s behavior, anatomy, and genetics, researchers concluded that there was “strong evidence” that these tree mice belong to a recently found “echolocating lineage within mammals.”
Are there other undiscovered creatures that echolocate? “I think it’s very likely,” Kloepper states. Kloepper says it’s challenging to determine which animals other than birds and mammals exhibit this behavior, considering “just how little we know about vocalizations of many cryptic species.”
Like bats, humans don’t have the natural ability to sense echolocation. However, we can use it. In his 1944 article, Griffin discussed an example of captains who listen for the echoes from ship horns in walls or are blinded by their canes’ movements.
Perhaps the most well-known human who echolocates can is Daniel Kish, the president of World Access for the Blind and who shared how he navigates by tapping the tongue in the 2020 Popular Science interview. “The longer the time delay between the noise emitted and the return,” Kish stated, “the farther away an object is.” Kish has coached people to do what they do on his own. Similar examples demonstrate that humans’ echolocation does not require extraordinary brain or sound hearing. It’s an acquired skill that can be learned over approximately ten weeks of practice and education.