The question of whether animals possess their own language has captivated people for centuries. The definitive answer rests entirely on the specific criteria used to define “language” itself. Linguists differentiate between simple communication, which is the transfer of information, and true language, which requires specific structural and cognitive properties. Exploring these distinctions allows for a clearer understanding of sophisticated animal communication systems compared to human linguistic ability.
The Scientific Criteria for Language
Human language is characterized by specific design features that set it apart from other forms of communication. The first is productivity, or open-endedness, which is the ability to generate and understand an infinite number of new messages from a finite set of sounds or words. This allows a speaker to create a sentence that has never been spoken before, and a listener can instantly grasp its meaning.
Another defining trait is displacement, the capacity to communicate about things not physically present in the immediate moment. Humans regularly talk about the past, the future, or abstract concepts, a feat rarely demonstrated in animal signaling. Furthermore, arbitrariness dictates that there is no inherent physical connection between a signal and the object it represents. For example, the sound sequence “dog” does not physically resemble the animal, illustrating a conventional relationship that must be learned. These three features—productivity, displacement, and arbitrariness—form the basis for analyzing animal communication.
Diverse Communication Methods in the Animal Kingdom
Animals utilize a variety of sensory channels to convey information, employing signals adapted to their environment. Visual communication includes displays like the honeybee waggle dance, which communicates information about a distant food source. The direction of the waggle run indicates the angle of the food source away from the sun, while the duration conveys the distance. This demonstrates symbolic representation and displacement, though the message is fixed to resource location.
Acoustic communication is common in environments where visibility is limited, such as the ocean or dense forests. Humpback whales produce complex, patterned songs that travel across vast ocean basins for social bonding and mating. Orcas use distinct dialects of whistles and pulsed calls unique to their social pods, suggesting cultural transmission across generations.
Chemical communication relies on pheromones, which are signals released by an animal to influence the behavior or physiology of others of the same species. These signals serve functions including attracting mates, marking territory, and coordinating social behavior within colonies. For example, the Queen substance in honeybees regulates worker reproduction and behavior, controlling complex social organization.
Analyzing Animal Systems for Grammar and Syntax
A deeper analysis of animal signals focuses on whether they combine elements in a structured way that changes the overall meaning, a process known as syntax. Vervet monkeys, for instance, use acoustically distinct alarm calls for specific predators. A “leopard call” sends others running up a tree, while an “eagle call” causes them to look skyward. These calls are semantic, referring to an external object, but the system is limited to a small, fixed vocabulary.
Some species demonstrate rudimentary forms of compositionality, where combining two signals creates a new meaning. Japanese great tits produce an ‘ABC’ call to scan for danger and a ‘D’ call to approach a caller. When combined as ‘ABC-D’, the call directs other tits to ‘scan for danger then approach the caller’. If the notes are played in the reverse order, ‘D-ABC’, the sequence is ignored, indicating that the order is meaningful.
Campbell’s monkeys also use a limited form of structural modification by adding a specific suffix, ‘-oo,’ to their general alarm calls. A “krak” call signals a serious leopard threat, but “krak-oo” attenuates the message to indicate a less urgent, non-ground disturbance. These examples show that animals can use combinatorial rules, but their systems are bounded and non-generative. They cannot create the limitless novel expressions characteristic of human language.
Can Animals Acquire Human Language?
Decades of research have attempted to teach animals human language systems, primarily focusing on great apes and marine mammals. The chimpanzee Washoe learned approximately 350 signs of American Sign Language (ASL) and could spontaneously combine them, such as signing “water bird.” However, her multi-sign combinations often lacked consistent grammatical structure, exhibiting only limited use of syntax.
The bonobo Kanzi, exposed to spoken English and a visual lexigram system, demonstrated remarkable comprehension abilities. Kanzi correctly followed novel commands, including “reversible sentences” that required understanding word order. This suggests an ability to process rudimentary grammatical rules in comprehension.
Dolphins have also shown impressive capacity in understanding artificial language systems, responding correctly to novel commands delivered through acoustic or gestural signals. These experiments confirm that several species possess the cognitive capacity to learn hundreds of arbitrary symbols and recognize basic syntactic ordering. However, the animals consistently fail to produce language with the infinite productivity and complex, hierarchical grammar innate to human language.