This article provides an empirically based, interdisciplinary approach to the following two questions: Do animals possess behavioral and cognitive characteristics such as culture, language, and a theory of mind? And if so, what are the implications, when long-standing criteria used to justify differences in moral consideration between humans and animals are no longer considered indisputable? One basic implication is that the psychological needs of captive animals should be adequately catered for. However, for species such as great apes and dolphins with whom we share major characteristics of personhood, welfare considerations alone may not suffice, and consideration of basic rights may be morally warranted—as for humans. Although characteristics supporting the status of personhood are present to differing degrees among the diverse array of animal species, this is a barrier to moral consideration only if anthropocentric, exclusive, and monolithic viewpoints about the necessary prerequisites for personhood are applied. We examine the flaws inherent within such positions and argue for inalienable species-appropriate rights.