What is psycholinguistics? - Animal communication

Can the messages and sounds made by animals be seen as 'language'?
Linguist, Charles Hockett looked at the properties within human language, but are these properties unique to human language? Or can they be applied to other communication systems? What about animals?[1]

Charles Hockett originally designed a list of 13 design features of human spoken language, with animal communication sharing some but never all or even most of these 13:

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The evolution of language in terms of the design features of language

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The Language of Bees
Worker bees perform a 'waggle dance' in which they turn in circles and move their bodies to indicate how close a food source is. The dance is specific to worker bees and is believed to be innate rather than learnt. The communication of bees shares some of Hockett's design features such as displacement. However the language of bees is not arbitrary as the signals used relate physically to the message, they are indexical, rather than being symbolic.

The Language of Chimps
It has been questioned whether animals are cognitively able to aquire language as humans do, and this has led to the research of cognitive and linguistic abilities of animals such as chimpanzees. Although chimpanzees have been found to be able to communicate with humans using keyboards, it is still unclear whether the use of the keyboards to signal is symbolic or indexical. It is also unanswered whether they are aware of underlying structures and word orders in the language.[2]