10They Play Music On The Web
A spider plays music on its web, using the vibrations as though it were a plucked guitar string. This fetches information about its mate, its prey, and even the strength and flexibility of its web. “Most spiders have poor eyesight and rely almost exclusively on the vibration of the silk in their web for sensory information,” says Beth Mortimer of Oxford University. “The sound of silk can tell them what type of meal is entangled in their net and about the intentions and quality of a prospective mate.” The echoes also give accurate information about the condition of the web. Spiders can feel these incredibly small vibrations through organs on their legs (known as “slit sensillae”). By tuning the silk, spiders can control and adjust the properties of the silk as well as the way the individual threads interconnect with one another. Researchers have shot bullets and lasers at the silk to measure its vibrations. Spider silk is tough but still able to transfer even the slightest information effectively. For humans, these sonic properties may inspire the creation of new lightweight technologies such as intelligent sensors.
9They Insult Each Other And Flip The Bird
You may think that sparrows are being friendly neighbors when they share songs, but it’s actually their way of insulting each other. “Song-sharing, where birds sing a smaller number of their species’s greatest hits, is a more aggressive and attention-seeking behavior,” says researcher Janet Lapierre from the University of Western Ontario. “It’s also a behavior most often displayed by belligerent older males.” Sparrows have “tough” neighborhoods where a greater percentage of the birds aggressively share songs and “mild-mannered” neighborhoods where the sparrows are more laid-back and avoid sharing songs. But it doesn’t stop there. Sparrows are not above defending their territory by flashing rude gestures at intruders, much like an upraised middle finger. First, the defending sparrow will match the song of the invading bird. If that doesn’t work, the defender progresses to a menacing “soft song.” Next is wing-waving. The defending sparrow will furiously vibrate one wing at a time. It may look innocent to us, but other birds know that wing-waving is an ominous signal. If the intruder still doesn’t get the message and back off, the defending sparrow is likely to attack. In a study of 48 sparrows, 31 attacked after this sequence of singing and wing-waving. A few birds bluffed with song-matching but didn’t actually attack. The most aggressive sparrows, called “under-signalers,” attacked without singing. “This is one of the most complicated communication systems outside of human language,” says lead researcher Caglar Akcay. “Here, we find that if a sparrow matches the intruder’s song as the intruder invades his territory, this almost always predicts that he will eventually attack the intruder.”
8They Have Hit Singles And Even Do Remixes
Male humpback whales in the South Pacific have chart-topping mating songs that usually spread from west to east over a period of one mating season. It’s their version of a catchy pop song. Researchers from the University of Queensland believe that this may be explained in one of two ways. A few male humpbacks may move to new groups and introduce their songs to another population. The other theory is that humpbacks in nearby groups may overhear the new songs when they migrate together through the ocean. The songs are often “remixes,” containing material from the previous season. “It would be like splicing an old Beatles song with U2,” says researcher Ellen Garland. “Occasionally, they completely throw the current song out the window and start singing a brand new song.” The male humpbacks sing only one song at a time in any location. But they innovate quickly, taking only two or three months for all regional whales to change to the same new song. Researchers don’t know if male humpbacks sing to pick up females or to warn off their male competitors. “We think this male quest for song novelty is in the hope of being that little bit different and perhaps more attractive to the opposite sex,” says Garland. “This is then countered by the urge to sing the same tune, by the need to conform.” Just like in humans.
7Cuckolded Males Carry On
Male songbirds sing to seduce their mates and warn off male rivals. When females want to pick a mate, they listen for characteristics in the male’s song to figure out if he can produce strong, healthy babies. With canaries, the females listen for “sexy syllables” in the male’s song. But with rock sparrows, researchers found that the males were graded by their women on the loudness, pitch, and tempo of their songs. A male rock sparrow sings the same element over and over as his song. The more successful males are older and sing with a slower pace and higher pitch than their younger rivals. Even without their songs, older males are believed to have a higher status in the rock sparrow world. Older males’ ability to sing a more appealing song just increases their attractiveness to the female rock sparrows. However, the females still cheat on the old guys. Researchers found that the male rock sparrows with the loudest songs had a greater chance of losing paternity in their own nest. In other words, a cheating mate returned to the nest with its lover’s offspring, which is known as “extra-pair young.” Older males had a bigger problem with this than younger males. But, not to be outdone by the women, the older males then turned around and cheated with other females. By the time they were done, the older male rock sparrows had sired a greater number of extra-pair young. They had the most reproductive success. The younger males had no choice when their mates cheated except to wait for another chance the following year. But, whether young or old, cuckolded male rock sparrows sang louder, possibly in response to their cheating mates being away from the nest.
6Ladies Love The Rock Stars
Like a bird, the male Alston’s singing mouse of Central America attracts its mate with its songs. But even with mice, ladies love the rock stars. Researchers discovered that female mice of this species prefer more difficult, flashier songs, the first time such a trait has been documented in mammals. It’s believed that female mice use the male’s singing ability to determine his suitability as a mate. “What makes a great performance is how rapidly males can repeat notes while maintaining a large range of frequencies of each note,” says researcher Bret Pasch. “Female preference seems to be based on how well males perform songs.” The male mice sing high-pitched vocal trills, but they have a physical limitation that causes a performance trade-off. If the male mouse trills faster (as the ladies prefer), its notes are lower-pitched. The researchers compare it to clapping your hands. The faster you clap, the less time there is to pull your hands apart to produce the force for a loud clap. At a certain point, you can’t clap loudly and rapidly. By neutering some male mice, the researchers also discovered that the loss of the male sex hormone androgen caused the mice to trill lower and slower. These biologists believe that androgens may cause a mouse’s jaw muscles to move faster and its diaphragm to expel air more forcefully.
5Most Romantic Animal Singer
The prize for most romantic singer in the animal kingdom goes to the male Mexican free-tailed bat. This bat is dark brown, about 10 centimeters (4 in) long, and is commonly seen in the southwestern US as well as Canada and South America. Most animals use visual cues, like a bird’s colorful feathers, to get a mate. But a male bat only uses sound. With limited time to attract a mate to his roost, he has to capture a female’s attention immediately. The bats reach speeds of 10 meters (30 ft) per second. “They only have about one-tenth of a second to get the female’s attention,” explains Mike Smotherman of Texas A&M University. So the male bat uses a special song to get the female’s attention as she’s flying by. But once she comes into his roost, he quickly and creatively remixes his musical phrases into different songs. Researchers believe this is a way for the male bat to keep a female interested until mating begins.
4They Have Regional Accents
Crested gibbons, which belong to the genus known as small apes, share our human characteristic of communicating with regional accents or even dialects. These crested gibbons roam the jungles of Cambodia, China, Laos, and Vietnam. They don’t speak like we do. Instead, they sing long-distance duets to seduce their mates and map out their territories. Their songs form a type of background noise in the jungle much like bird songs. Researchers analyzed the songs of 400 gibbons from 92 groups in 24 different areas. “Each gibbon had its own variable song,” says evolutionary biologist Van Ngoc Thinh. “But, much like people, there is a regional similarity between gibbons within the same location.” The several southern species sounded similar but had mild variations in their lilts and dips. It’s the minor difference you’d hear if you compared the accents of people living in adjacent Southern counties in the US. But some of the northern species sounded much different from each other and their southern counterparts. Think of it as the difference between a Boston accent and a Chicago one. According to the research team, that means the gibbons originated in the north and migrated south. Unlike birds, which have to learn their songs, gibbons are born with their songs encoded in their DNA. Their tunes evolve over time at the rate that their genetic code changes.
3They’re Not Getting Older, They’re Getting Better
Like the male rock sparrow we talked about earlier, older male nightingales can sing better than their younger counterparts, and the ladies prefer the old guys. But unlike the male rock sparrows that just keep repeating one musical element in their songs, male nightingales are among the most sophisticated singers of all birds. Nightingales are also fast singers, trilling up to 100 elements per second. They have a huge repertoire of about 200 different kinds of songs. But it would take around an hour for a female nightingale to listen to a male’s entire playlist. So zoologists believe the females assess the quality of specific elements or kinds of songs to determine which bird would be a good mate. One-fifth of the male’s songs have rapid broadband trills, which are physically difficult for the bird to perform. So the ability to trill well is a sign of good health in a male nightingale. Older male nightingales trill faster and with a larger range of notes than younger male nightingales. This allows the females to identify the older birds, with whom they prefer to mate because older males have the most reproductive success.
2They Talk About The Kids
Giant South American river turtles congregate in large groups during nesting season, which starts when the turtles escape the forest during flood season to nest on the beach along the river bank. Researchers captured 270 different turtle sounds on their recordings. As they tried to match sounds to behaviors, they found that the turtles made low-pitched sounds when they basked or moved through the river. This might make it easier to communicate with other turtles over long distances. But nesting sounds were usually higher-pitched. This may happen because higher-pitched sounds move through air and shallow water better. The greatest variety of sounds came from the female turtles as they began to nest. Although the researchers can’t be sure, they believe these sounds help the turtles agree on a nesting site and coordinate their movements out of the water in single file. Even baby turtles make noise before they hatch, which may influence the babies to hatch as a group. The female adult turtles then seem to respond vocally to the hatchlings’ sounds, which may be the way adults guide their kids into the water. The adult females migrate with their children for over two months.
1They Talk Dirty
Originally, moths may have developed ears to hear and avoid their worst predator, bats. But over time, they adapted their ears and their use of sound to communicate sexually. Researchers from the University of Tokyo studied this behavior in two different species of moth. The Asian corn borer moth makes sounds like a bat to fool the female moth into freezing to escape the bat’s attention. The female can’t tell the difference between the two sounds. For the male moth, it’s easier to mate with the female when she doesn’t move. The male Japanese lichen moth also makes sounds like a bat when it wants to mate. But these females can tell the difference between a bat and a male moth. They’re more evolved. In both cases, however, the moths “whisper” their sounds so they don’t accidentally attract hunting bats. Humans don’t hear it because it’s ultrasound. On the other hand, lyrebirds want to be heard when they talk dirty. These native Australian songbirds can accurately mimic everything from a baby’s cry to the sound of a laser gun. They use a vocal organ called the syrinx, which is extremely flexible in this type of bird. Male lyrebirds do short imitations to surprise and retain the attention of the females, who judge the males’ dexterity. The more impressive the imitation, the more chance a male has to mate.
