Animal language


Animal languages are forms of communication between non-human animals that show similarities to human language. Animals communicate through a variety of signs, such as sounds and movements. Signing among animals may be considered a form of language if the inventory of signs is large enough, the signs are relatively arbitrary, and the animals seem to produce them with a degree of volition.
The current academic consensus is that animal communication systems lack key aspects that might define them as languages, one such aspect being humans' creation of new patterns of signs under varied circumstances. Humans routinely produce entirely new combinations of words. Some researchers, including the linguist Charles Hockett, argue that human language and animal communication differ so much that the underlying principles are unrelated. Accordingly, linguist Thomas A. Sebeok has proposed to not use the term "language" for animal sign systems. However, other linguists and biologists, including Marc Hauser, Noam Chomsky, and W. Tecumseh Fitch, assert that an evolutionary continuum exists between the communication methods of animal and human language.

Aspects of human language

Some experts argue the following properties separate human language from animal communication:
  • Arbitrariness: In language, there is almost never a rational or predictable relationship between a sound or sign and the meaning of that sound or sign. For example, there is nothing intrinsically house-like about the word "house", which is casa in Spanish, maison in French, and ie in Japanese.
  • Discreteness: Language is composed of small, separate, and repeatable parts that are used in different combinations to create meaning.
  • Displacement: Language is able to communicate about concepts or objects that are not in the immediate vicinity, either spatially or temporally.
  • Duality of patterning: A small set of sounds that are meaningless in isolation, when used in different combinations, produces an enormous set of linguistically meaningful units. Thus, a language's collection of only tens or dozens of phonemes often produces tens of thousands of basic words. This is also referred to as double articulation.
  • Productivity: The above also relates to how users can understand and create an indefinitely large number of utterances. A huge but finite set of words can be combined to create nearly-infinite meaningful possible sentences.
  • Semanticity: Specific signals have specific meanings.
Research with apes, like that of Francine Patterson with Koko or Allen and Beatrix Gardner with Washoe, suggested that apes are capable of using limited degrees of language that meet some of these requirements, including arbitrariness, discreteness, and productivity.
In the wild, chimpanzees have been seen "talking" to each other when warning about approaching danger. For example, if one chimpanzee sees a snake, said chimpanzee may make a low, rumbling noise, signaling for all the other chimps to climb into nearby trees. In this case, the chimpanzees' communication does not indicate displacement, as it is entirely contained to an observable event.
Arbitrariness has been noted in meerkat calls; bee dances demonstrate elements of spatial displacement; and cultural transmission has possibly occurred through language between the bonobos named Kanzi and Panbanisha.
Claims that animals have language skills akin to humans, however, are extremely controversial. In his book The Language Instinct, Steven Pinker illustrates that claims of chimpanzees acquiring language are exaggerated and rest on very limited or specious evidence.
The American linguist Charles Hockett theorized that there are sixteen features of human language that distinguish human communication from that of animals. He called these the design features of language. The features mentioned below have so far been found in all spoken human languages, and at least one is missing from any other animal communication system.
  • Vocal-auditory channel: Sounds are emitted from the mouth and perceived by the auditory system. While this applies to many animal communication systems, there are many exceptions, such as those relying on visual communication. One example is cobras extending the ribs behind their heads to send the message of intimidation or of feeling threatened. In humans, sign languages provide many examples of fully formed languages that use a visual channel.
  • Broadcast transmission and directional reception: This requires that the recipient can tell the direction that the signal comes from and thus the originator of the signal.
  • Rapid fading : The signal lasts a short time. This is true of all systems involving sound. It does not take into account audio recording technology and is also not true for written language. It tends not to apply to animal signals involving chemicals and smells which often fade slowly. For example, a skunk's smell, produced in its glands, lingers to deter a predator from attacking.
  • Interchangeability: All utterances that are understood can be produced. This is different from some communication systems where, for example, males produce one set of behaviors and females another and they are unable to interchange these messages so that males use the female signal and vice versa. For example, Heliothine moths have differentiated communication: females are able to send a chemical to indicate preparedness to mate, while males cannot send the chemical.
  • Total feedback: The sender of a message is aware of the message being sent.
  • Specialization: The signal produced is intended for communication and is not due to another behavior. For example, dog panting is a natural reaction to being overheated, but is not produced to specifically relay a particular message.
  • Semanticity: There is some fixed relationship between a signal and a meaning.

    Primates

Humans are able to distinguish real words from fake words based on the phonological order of the word itself. In a 2013 study, baboons were shown to have this skill as well. The discovery has led researchers to believe that reading is not as advanced a skill as previously believed, but instead based on the ability to recognize and distinguish letters from one another. The experimental setup consisted of six young adult baboons, and results were measured by allowing the animals to use a touch screen and select whether or not the displayed word was a real word, or a non-word such as "dran" or "telk". The study lasted for six weeks, with approximately 50,000 tests completed in that time. The researchers minimized common bigrams, or combinations of two letters, in non-words, and maximized them in real words. Further studies will attempt to teach baboons how to use an artificial alphabet.
In a 2016 study, a team of biologists from several universities concluded that macaques possess vocal tracts physically capable of speech, "but lack a speech-ready brain to control it".

Non-primates

Among the most studied examples of non-primate languages are:

Vertebrates

Birds

  • Bird songs: Songbirds can be highly articulate, with many species having a large variety of complex songs. They are not fully understood but are associated with courtship and territory. Songs are copied, not innately known, and exposure to birdsong is necessary early in a songbird's life, or its communication skills will be permanently harmed. Bird songs are distinct from calls, with calls typically being short, simple and with an urgent functional purpose, such as raising the alarm over a nearby predator.
  • Parrots: Parrots, especially Grey parrots and macaws, are well known for their ability to mimic human language. They can be trained to identify objects and answer simple questions. One specimen, Alex, was taught at least 100 English words, could solve basic mathematical equations, and his intelligence was often compared to a human toddler.
  • Corvids: Crows, ravens and some other corvids can accurately mimic human words and phrases, but unlike parrots they do not seem able to use those words to answer human questions. This is despite crows having amongst the best tool-use and problem solving skills out of all animals, including being able to understand recursion.

    Mammals

  • African forest elephants: Cornell University's Elephant Listening Project began in 1999 when Katy Payne began studying the calls of African forest elephants in Dzanga National Park in the Central African Republic. Andrea Turkalo has continued Payne's work in Dzanga National Park by observing elephant communication. For nearly 20 years, Turkalo has used a spectrogram to record the noises that the elephants make. After extensive observation and research, she has been able to recognize elephants by their voices. Researchers hope to translate these voices into an elephant dictionary, but this will likely not occur for many years. Because elephant calls are often made at very low frequencies, the spectrogram is designed to detect lower frequencies than humans can perceive, allowing Turkalo to better understand the elephants' noise making. Cornell's research on African forest elephants has challenged the idea that humans are considerably better at using language than animals, and that animals only have a small set of information they can convey to others. As Turkalo explained, "many of their calls are in some ways similar to human speech." Elephants in captivity can be taught to remember tone, melody, and recognise more than 20 words.
  • Mustached bats: Since these animals spend most of their lives in the dark, they rely heavily on their auditory system to communicate, including via echolocation and using calls to locate each other. Studies have shown that mustached bats use a wide variety of calls to communicate with one another. These calls include 33 different sounds, or "syllables", that the bats either use alone or combine in various ways to form composite syllables.
  • Prairie dogs: Con Slobodchikoff studied prairie dog communication and discovered that they use different alarm calls and escape behaviors for different species of predators. Their calls transmit semantic information, which was demonstrated when playbacks of alarm calls in the absence of predators led to escape behavior appropriate for the types of predators associated with the calls. The alarm calls also contain descriptive information about the general size, color, and speed of the predator.