Interspecies communication is communication between different species of animals, plants, fungi or bacteria. Interspecies communication research in the sciences and the arts has produced results, giving hope that we may someday be able to communicate with certain animals on an advanced level.
Recent research with Kanzi a bonobo at the University of Georgia represents a successful experiment where (1) the bonobo learned symbols and is successfully communicating with its trainers Jared Taglialatela, Sue Savage-Rumbaugh and Lauren Baker. Their work is contributing to a now larger series of research studies that language is an evolutionary trait that evolved in our non-human primates.
Cooperative interspecies communication implies the sharing and understanding of information from two or more species that work towards the benefit of both species (mutualism). Most research has found cooperative communication in prey animals whose alarm calls not only alert conspecifics but also heterospecifics. So far, most work has been found in primates. Redfronted lemur and sifakas have reciprocal recognition of one another’s alarm calls. The same has been found in West African Diana monkey and Campbell’s monkeys. When one species elicits an alarm signal specific to a certain predator, the other species react in the same pattern as the species that called. For example, leopards hunt on both species by capitalizing the elements of stealth and surprise. If the monkeys detect the leopard before it attacks (usually resulting in mobbing), the leopard will typically not attack. Therefore, when a leopard alarm call is given both species respond by positioning near the leopard signaling that it has been found out. It also seems that the monkeys are able to distinguish a leopard alarm call from, for example, a raptor alarm call. When a raptor alarm call is given, the monkeys respond by moving towards the forest floor and away from aerial attack. Therefore, it is not simply that the monkeys act upon hearing the alarm calls but rather they are able to actually extract particular information from a call. Increased vigilance obviously has its benefits since more eyes watching mean earlier detection of predators and lower risk of being eaten. Responses to heterospecific alarm calls are not confined to simian species but have also been found in the Sciuridae species: yellow-bellied marmot and the golden-mantled ground squirrel.
Whether heterospecific understanding is a learned behavior or not is also of interest. Ramakrishnan and Coss (2000) found that age and interspecies experience were important factors in the ability for bonnet macaques to recognize heterospecific calls. Macaques who were younger and exposed longer to other species’ alarm calls were more likely to correctly respond to heterospecific alarm calls. A key component of this early learning was the reinforcement of a predatory threat. That is, when an alarm call was given a corresponding threat had to be presented in order to make the association. Therefore, interspecies communication may not be an innate ability but rather a sort of imprinting that may have to be coupled with an intense emotion (fear) early in life. In fact, most interspecies communications reported typically involve an older animal taking care of a younger animal of a different species. For example, Owen and Mzee, the odd couple of an orphaned baby hippopotamus and a 130-year old Aldabran tortoise, display a relationship rarely seen in the animal world. Dr. Kahumbu of the sanctuary that holds the two believes that the two actually vocalize to one another in neither a stereotypical tortoise nor a hippopotamus fashion. Interestingly, Owen also does not respond to hippopotamus calls. It is likely that when Owen was first introduced to Mzee he was still young enough where imprinting could occur.
Parasitic communication and eavesdropping
Unlike cooperative communication, parasitic communication involves an unequal sharing of information (parasitism). In terms of alarm calls, this means that the warnings are not bi-directional. However, it would be faulty to say that the eavesdroppers are not giving any information in return. It may be that the other species has simply not been able to decipher the eavesdroppers’ calls. Much of the research done on this type of communication has been found in bird species, including the nuthatch and the great tit. In 2007, Templeton and Greene found that nuthatches are able to discriminate between subtle differences in chickadee alarm calls, which broadcast the location and size of a predator. Since chickadees and nuthatches typically occupy the same habitat, mobbing predators together acts as a deterrent that benefits both species. The team also found that nuthatches screen chickadee alarm calls in order to determine whether it is cost-efficient to mob a particular predator. This is because not all predators pose the same risk to nuthatches as to chickadees. Templeton and Greene speculate that screening may be most important in the winter when energy demands are the highest.
Work by Gorissen, Gorissen, and Eens (2006) has focused on blue tit song matching (or, “song imitation”) by great tits. Blue and great tits compete for resources such as food and nesting cavities and their coexistence has important fitness consequences for both species. These fitness costs might promote interspecific aggression because resources need to be defended against heterospecifics as well. So, the use of efficient vocal strategies such as matching might prove to be effective in interspecific communication. Hence, heterospecific matching could be a way of phrasing a threat in the language of the heterospecfic intruder. It could equally be well argued that these imitations of blue tit sounds have no function at all and are merely the result of learning mistakes in the sensitive period of great tits because blue and great tits form mixed foraging flocks together. While the authors agree with the first hypothesis, it is plausible that the latter also being true given the data on age and experience in primates.
In addition to birds, eavesdropping has been found in tungara frogs and their sympatric heterospecifics. The scientists posit that mixed-species choruses may reduce their risk of predation without increasing mate competition.
Much of the communication between predators and prey can be defined as signaling. In some animals, the best way to avoid being preyed upon is an advertisement of danger or unpalatability, or aposematism. Given the effectiveness of this, it is no surprise that many animals employ styles of mimicry to ward off predators. Some predators also use aggressive mimicry as a hunting technique. For example, Photuris fireflies mimic female Photinus fireflies by scent and glow patterns in order to lure interested male Photinus fireflies, which they then kill and eat. Lophiiformes, or anglerfish, are also famous for their use of escas as bait for small unsuspecting fish.
Recently, two interesting examples of predator-prey signaling were found in caterpillars and ground squirrels. When physically disturbed, Lepidoptera larvae produce a clicking noise with their mandibles followed by an unpalatable oral secretion. Scientists believe this to be “acoustic aposematism” which has only been previously found in a controlled study with bats and tiger moths. While the defense mechanisms of ground squirrels to predatory rattlesnakes have been well studied (i.e. tail flagging), only recently have scientists discovered that these squirrels also employ a type of infrared heat signaling. By using robotic models of squirrels, the researchers found that when infrared radiation was added to tail flagging, rattlesnakes shifted from predatory to defensive behavior and were less likely to attack than when no radiation component was added.
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According to Koko’s website, Koko is a 35 year-old lowland gorilla that learned to speak American Sign Language when she was just a baby. Her teacher, Dr. Penny Patterson, began working with Koko as a Ph.D. project at Stanford, thinking it would only be a 4-year study. Thirty-some years later, Penny and Koko continue to work together at the Gorilla Foundation in one of the longest interspecies communication studies ever conducted, the only one with gorillas. Koko now has a vocabulary of over 1000 signs, and understands even more spoken English.
On April 26, 1998, Koko the gorilla gave an AOL live chat. Koko’s trainer, Dr. Francine “Penny” Patternson, used sign language to relay the gorilla questions from the online audience; 7,811 AOL members participated, ranking the chat the fifth most popular in AOL's history. The following are two excerpts from the live chat, which illustrate the ambiguity of Koko’s true ability to communicate with humans. HaloMyBaby is the moderator of the chat, DrPPatrsn is Penny Patterson, and LiveKOKO is Koko.
- HaloMyBaby: ...MInyKitty asks Koko are you going to have a baby in the future?
- LiveKOKO: Pink
- DrPPatrsn: We've had earlier discussion about colors today
- LiveKOKO: Listen, Koko loves eat
- HaloMyBaby: Me too!
- DrPPatrsn: What about a baby? She's thinking...
- LiveKOKO: Unattention
- DrPPatrsn: She covered her face with her hands....which means it's not happening, basically, or it hasn't happened yet.
- LiveKOKO: I don't see it.
- HaloMyBaby: That's sad!
- DrPPatrsn: In other words, she hasn't had one yet, and she doesn't see it happening. She needs several females and one male to have a family. In our setting it really isn't possible for her to have a baby.
- Question: Do you like to chat with other people?
- LiveKOKO: fine nipple
- DrPPatrsn: Nipple rhymes with people, she doesn't sign people per se, she was trying to do a "sounds like..."
In the above excerpts, Dr. Patterson tries to interpret Koko’s nonsensical responses into ones that directly answer the question. It is also interesting to note that when Dr. Patterson says, “nipple rhymes with people” she is implying that Koko understands rhyme schemes and the sounds of the words in addition to their meanings; this is highly unlikely. While Koko undoubtedly knows how to sign words, it is questionable whether her form of signing represents a true understanding of the English language (see Controversy below). The same can be said of pet dogs that respond to human commands. Most of this is due to operant conditioning (e.g. “Sit” in order to get a biscuit). It is more likely to do with the sexual harassment/nipple fetish that was said to be taking place and easily chalked off as something similar to a Freudian slip. 
An important reminder for understanding human-animal communication is that many humans tend to anthropomorphize animals and thus believe that they have the capacity to understand human speech and language. Given evidence for socialization and interspecies communication, it would be interesting to see how much knowledge pets can gain from humans and vice versa.
Interspecies communication is a field of considerable debate as there is no concrete definition of what constitutes communication. Does it involve a full comprehension of language or are knowing simple words enough? For instance, while it’s questionable that Koko really understands the English language, is she still communicating because she knows how to sign for things she wants? Is this the same as a dog learning to bark for food? It is also important to make a distinction between this and signaling. Signaling implies a tacit exchange of information usually in the forms of color, odor, and gesture but the definition is certainly not limited to this interpretation. The species listed in this paradigm may not be representative of all interspecies communication simply because they are all vertebrates and of certain social interaction. It has been documented that bacteria, pathogens, plants, and fungi engage in transfers of information. There is no reason why the categories stated in this article are more accurate than other theories and so leaves open the question of semantics.
Another example of human-animal interaction is animal telepathy, where human psychics claim to communicate with animals by reading their minds. There is no scientific evidence supporting these claims.
- Animal communication
- Clever Hans
- Great ape language
- Human-animal communication
- Jim Nollman
- John C. Lilly
- The New Scientist: Lab chimp speaks his own language 10:15 2 January 2003 by Anil Ananthaswamy
- Doctor Dolittle's Delusion, Subtitle: Animals and the Uniqueness of Human Language Published: 2004 Yale University Press by Anderson
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- Zuberbuhler, K. (2000) Interspecies semantic communication in two forest primates. Proc R Soc Lond Ser B Biol Sci 267:713–718.
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- Ramakrishnan, U. and Coss, R. G. (2000) Recognition of Heterospecific Alarm Vocalization by Bonnet Macaques (Macaca radiata). Journal of Comparative Psychology 114:3-12.
- Owen & Mzee
- Templeton, C.N. and Greene, E. (2007) Nuthatches eavesdrop on variations in heterospecific chickadee mobbing alarm calls. PNAS 104:5479-5482.
- Gorissen,L.; Gorissen,M.; Eens,M. (2006) Heterospecific song matching in two closely related songbirds (Parus major and P. caeruleus): Great tits match blue tits but not vice versa. Behavioral Ecology and Sociobiology 60:260-269.
- Phelps, S.M.; Rand, A.S.; Ryan, M.J. (2007) The mixed-species chorus as public information: túngara frogs eavesdrop on a heterospecific. Behav. Ecol. 18:108-114.
- Brown, S.G.; Boettner, G.H.; Yack, J.E. (2007) Clicking caterpillars: acoustic aposematism in Antheraea polyphemus and other Bombycoidea. J Exp Biol 210:993-1005.
- Hristov, N. I. and Conner, W. E. (2005) Sound strategy: acoustic aposematism in the bat–tiger moth arms race. Naturwissenschaften 92: 164-169.
- Rundus, A.S.; Owings, D.H.; Joshi, S.S.; Chinn, E; Giannini, N. Ground squirrels use an infrared signal to deter rattlesnake predation. Proceedings of the National Academy of Sciences 104:14372-14376.
- Koko.org / The Gorilla Foundation
- "Gorilla breast partialism' women sue". http://news.bbc.co.uk/2/hi/americas/4280961.stm (BBC News). 20 February 2005. Retrieved 13 July 2011.