It is a common intuition that animals communicate among themselves and even with us humans. But what is animal communication? Our intuition suggests that we can apply the same concept of communication to both animals and humans. But is there a theoretical account of communication that can vindicate this intuition? And if there is, what is the payoff of such an account? These are the questions that I address in this paper. I argue that vindicating the intuition that animals communicate (...) like humans do is more challenging than one might initially think. I show that the dominant accounts of animal and human communication in the literature (i.e. biological, information and Gricean) are neither designed nor able to vindicate this intuition. I then derive two basic constraints on what should count as a plausible Maximally Unified Account of animal and human communication (MUA), i.e. an account that is able to vindicate the intuition, discussing two accounts that meet these conditions: Millikan’s theory of intentional signs (2004; 2017) and Green’s theory of organic meaning (2019). Finally, I assess the utility of an MUA such as Millikan’s and Green’s in the studies of animal and human communication. (shrink)