Communication in the World Around Us
Communication in the World Around Us
“Without communication, each individual would merely be an island isolated from all other such islands.”—The Language of Animals.
IN A patch of forest, a savanna, or even in your own garden, any number of animals might be busily communicating with one another. The book The Language of Animals says: “Animals use every sense, gesturing with appendages and body position; sending and receiving subtle—or not so subtle in the case of frightened skunks—odor signals; squeaking, squawking, singing and chirping; sending and receiving electrical signals; flashing lights; changing skin pigmentation; ‘dancing;’ and even tapping and vibrating the surface they walk on.” But what do all these signals mean?
Scientists discover the meaning of animal signals through careful observation. For example, they have observed that when a bantam (small domestic fowl) sees a ground predator such as a weasel, the bantam makes a high-pitched kuk, kuk, kuk sound to warn other bantams. But if it spots a hawk, a bantam emits a single long shriek. Each call elicits a prompt response that accords with the threat, indicating that the birds communicate meaningful information. Other birds have been observed making similar discriminating calls.
“One of the main ways to study communication in animals,” says the book Songs, Roars, and Rituals, “is to record the signal of interest and then play it back to the animals and see whether they respond in a predictable way.” Tests with bantams gave the same results as were observed in the wild. The method works even with spiders. In order to determine what attracts female wolf spiders to courting males—which try to impress females by waving their hairy forelegs at them—researchers experimented by videotaping a male wolf spider and digitally removing the tufts of hair from its legs. When they played the video back to the female, she suddenly lost interest. The lesson? Female wolf spiders are evidently attracted only to males waving hairy legs!
Signaling With Scent
Many animals signal one another by secreting powerful chemicals called pheromones, usually from special glands, or by means of their urine or feces. Just as a fence and a nameplate or number identify the property of a human, pheromones flag and define the territory of certain animals, including dogs and cats. Although invisible, this most effective form of marking enables animals of the same species to keep an optimal distance from one another.
But pheromones do more than mark territory. They are like a chemical bulletin board that other animals “read” with great interest. Scent marks, says the book How Animals Communicate, “probably include additional information about the resident, such as its age, sex, physical strength and other abilities, [and] the current phase of the owner’s reproductive cycle . . . The scent of the animal’s mark acts as his passport for individual identification.” Understandably, some animals take their scent marks very seriously—a fact well-known to zookeepers. After washing down cages or runs, keepers have observed that many animals immediately remark their area. Indeed, “the absence of its own scent is stressful and may evoke abnormal behaviour and even sterility,” says the above reference.
Pheromones also play a big role in the insect realm. Alarm pheromones, for example, mediate swarming and attack behavior. Aggregation pheromones attract individuals to a food source or to a suitable nesting site. They include the sex pheromones, to which some creatures are acutely sensitive. Male silkworm moths have two elaborate antennae that look like tiny, delicate fern fronds. These antennae are so sensitive that they can detect a single molecule of female sex pheromone! Some 200 molecules will cause the male to begin searching for the female. Chemical communication, though, is not confined to animate life.
“Talking” Plants
Did you know that plants can communicate with one another and even with certain animals? Discover magazine reports that researchers in the Netherlands observed that lima bean plants, when attacked by spider mites, release a chemical distress call that attracts other mites that prey on the spider mite. Similarly, corn, tobacco, and cotton plants, when invaded by caterpillars, emit airborne chemicals that draw wasps—a lethal enemy of caterpillars. Said one researcher: “Plants are not just saying, ‘Yes, I am damaged,’ they are also saying specifically who is damaging them. It is such an intricate and fabulous system.”
Plant-to-plant communication is equally amazing. According to Discover, researchers have “caught willow, poplar, alder, and birch trees listening to their own kind and barley seedlings listening to other barley seedlings. In each case, damaged plants, whether eaten by caterpillars, infected by fungus or powdery mildew, [or] infested by spider mites, . . . sent out chemicals that seemed to jump-start the defenses of undamaged plants nearby.” Even unrelated plants have responded to chemical alarms.
When under attack or warned of one, a plant engages its own defenses. These include toxins that kill insects or compounds that impede or even stop the invader’s ability to digest the plant. Future research into this fascinating field may lead to more amazing discoveries, some of which may even benefit agriculture.
‘Morse Code’ With Lights
“Their little airborne lamps, winking on before the stars, endowed my ordinary suburban neighborhood with a wonderful kind of magic,” wrote ecologist Susan Tweit in an article about fireflies. These insects of the beetle family use a light-based vocabulary that “ranges from a simple warning glow to a complicated call-and-response flashing between potential mates,” says Tweit. The color of their light ranges from green to yellow to orange. Because females rarely fly, most of the flashing we see is that of males.—See the box “The Firefly’s Cold Light.”
Each of the 1,900 species of fireflies, also called lightning bugs, has a unique pattern of flashes. It might consist of three flashes, one second or so apart, or of a series of pulses of different lengths and intervals. When searching for a mate, a male flies about flashing his courting code. “A female cues in on the timing of the flashes,” says Audubon magazine, and “responds with a ‘Here I am’ flash at the interval appropriate to her species.” The male recognizes her silent invitation and flies to her.
Feathered Masters of Song
“In duration, variety and complexity, no other vocalisations produced by any other animal can match the song of a bird,” says David Attenborough in his book The Life of Birds. Birdsongs originate not in the throat but in an organ called the syrinx, deep within a bird’s chest near where the windpipe divides prior to entering the lungs.
The songs of birds are partly inherited and partly learned from parents. Hence, birds can even develop regional accents. Says The Life of Birds: “Blackbirds descended from those that were taken to Australia during the nineteenth century to gladden the ears of European settlers with sounds of home, now have very distinct Australian accents.” Male lyrebird vocalizations, which are said to be the most complex and melodious of all birdsongs, are almost entirely learned from other birds. In fact, lyrebirds are such gifted imitators that they can copy almost any sound they hear—including musical instruments, barking dogs, burglar alarms, the blows of an ax, and even camera motor drives! All this mimicry, of course, is mainly with a view to impressing a potential mate.
Woodpeckers, which normally use their beak to dig for food, are the percussionists of the avian world, signaling other birds by pounding their beak on a resonant hollow log or branch. Some may even “exploit exciting new instruments . . . , a corrugated iron roof or a metal stove-pipe,” says Attenborough. Birds also communicate visually, with or without musical accompaniment. For example, they might signal one another by flashing their beautifully colored feathers.
When advertising his territory, the male Australian palm cockatoo does it all—percussion, vocalization, rhythmic movements, and a feather show. He snaps off a suitable branch, grabs it with his foot, and taps it on a dead trunk. At the same time, he spreads his wings, fans out his crest, sways his head to and fro, and emits high-pitched shrieks—truly a spectacular performance!
Some birdcalls are recognized by other animals. Consider the honey guide, a small, thrushlike bird found mostly in Africa. True to its name, the honey guide, with its distinctive cry, will lead a ratel, a badgerlike member of the weasel family, to a tree containing a beehive. When the bird alights on or near the tree, it emits a different call that says, in effect, “Honey is near!” The ratel locates the tree, claws open the trunk, and indulges his sweet tooth.
Talking Underwater
Since the advent of hydrophones, underwater listening devices, researchers have been amazed at the many sounds emanating from the deep. Ranging from a low hum to a mew and even shrieks, these sounds are so abundant that submariners have exploited them to camouflage their own operational noises. But fish sounds are not without a pattern. In his book Secret Languages of the Sea, marine biologist Robert Burgess says: “Where one fish might ‘grunt, cluck, and bark,’ then repeat the performance precisely, another might ‘click and snap,’ then do a ‘scrape and rasp’ for an encore.”
Lacking vocal cords, how do fish make sounds? Some, says Burgess, employ muscles “attached to the walls of their balloonlike swim bladders to vibrate those walls until their bladders” resonate like drums. Other fish gnash their teeth or open and close their gill covers with a distinct thud or clap. Is all this just meaningless “chatter”? Apparently not. Like terrestrial animals, fish make sounds so as to “attract the opposite sex, for orientation, as a defense against enemies, and for general communication and intimidation,” says Burgess.
Fish also have good hearing. In fact, many species have inner ears as well as a line of pressure-sensitive cells that run along the midline of their flanks. This row of cells, called the lateral line, can detect the pressure waves created by sound as it travels through water.
Earth’s Preeminent Communicators
“When we study human language,” wrote professor of linguistics Noam Chomsky, “we are approaching what some might call the ‘human essence,’ the distinctive qualities of mind that are, so far as we know, unique to man.” Barbara Lust, professor of linguistics and human development, stated: “Children as young as 3 years of age already possess a remarkable knowledge of language structure and syntax which is so complex and precise that it must challenge any known learning theory to account for its acquisition.”
The Bible, however, does furnish a reasonable explanation for the miracle of human language. It attributes this gift to the Creator, Jehovah God, who made mankind in his “image.” (Genesis 1:27) But how are divine traits reflected in our language skills?
Take naming, for instance. Professor of speech communication Frank Dance wrote that humans “are the only creatures who can name.” That this is a divine trait is evident in Scripture. At the very start of the creation account, the Bible tells us that God called “the light Day, but the darkness he called Night.” (Genesis 1:5) According to Isaiah 40:26, God evidently gave each star its own name—a staggering achievement!
After God created Adam, one of the first projects he gave him was to name the animals. How that assignment must have challenged Adam’s powers of observation and creativity! Later, Adam named his wife Eve. She, in turn, called their first child Cain. (Genesis 2:19, 20; 3:20; 4:1, footnote) Since then, humans have spared no effort in naming every conceivable thing—and all in the interests of communication. Yes, think how difficult intelligent communication would be without names.
Besides having the ability and desire to name things, humans have many other communication skills, not all of which are verbal. Indeed, there is virtually no limit to what we can share with one another, from complex concepts to the most tender feelings. Yet, there is one particular form of communication that towers above all of these, as we will now see.
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THE FIREFLY’S COLD LIGHT
An incandescent light bulb loses over 90 percent of its energy as heat. A firefly’s light, which is based on complex chemical reactions, is 90 to 98 percent efficient, wasting next to nothing on heat. Hence, it is rightly called cold light. The light-forming chemical reactions occur in special cells called photocytes. Nerves turn the photocytes on and off.
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John M. Burnley/Bruce Coleman Inc.
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HELPFUL HINTS TO IMPROVE YOUR COMMUNICATION SKILLS
1. Listen with interest when others speak, and do not dominate conversations. People will overlook a mispronounced word or a slip in grammar, but they will not warm to someone who wants to talk but not listen. “Be swift about hearing, slow about speaking,” says the Bible.—James 1:19.
2. Take an interest in life and the things around you. Read widely but judiciously. When discussing what you learn, temper your conversation with modesty and humility.—Psalm 5:5; Proverbs 11:2.
3. Enlarge your vocabulary—but with practical words, not showy terms that draw attention to the speaker. People said of Jesus: “Never has another man spoken like this.” (John 7:46) Yet, even “unlettered and ordinary” people had no difficulty understanding Jesus’ words.—Acts 4:13.
4. Speak clearly, and pronounce words correctly. But avoid sounding overly precise or affected. When we speak articulately and refrain from slurring words or clipping off word endings, we dignify our speech and do a kindness to our listeners.—1 Corinthians 14:7-9.
5. Recognize that your communication skills are a divine gift. This will motivate you to accord those skills due respect.—James 1:17.
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Silkworm moths have extremely sensitive antennae
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Courtesy Phil Pellitteri
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Woodpecker
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Bird of paradise
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© Michael S. Yamashita/CORBIS
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Palm cockatoo
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Roland Seitre