Yet zebra finches have complicated structure in their songs, dolphins can understand differences in word order and even some monkeys in the wild seem to use one type of call to modify another.
The list of abilities that were formerly thought to be a unique part of human language is actually quite long. It includes parts of language, such as words. Vervet monkeys use wordlike alarm calls to signal a specific kind of danger. Another crucial aspect is structure. Because we have syntax, we can produce an infinite number of novel sentences and meanings, and we can understand sentences that we have never heard before. Yet zebra finches have complicated structure in their songs, dolphins can understand differences in word order and even some monkeys in the wild seem to use one type of call to modify another. The list extends to types of cognition, such as theory of mind, which is the ability to infer others' mental states. Dolphins and chimpanzees are excellent at guessing what an interlocutor wants. Even the supposedly unique ability to think about numbers falls by the wayside—bees can understand the concept of zero, bees and rhesus monkeys can count to four, and cormorants used for fishing in China reportedly count to seven.