Feral animals are those that live in the wild but are descendants of domesticated populations. Although, in many cases, these feral populations imply a demonstrable risk to the ecosystems in which they live and may conflict with local wild species and human activities, there are feral populations that are considered worth preserving and, in some cases, they already enjoy protection by interest groups and even public authorities. In this review, we aim to identify valuable populations using three criteria: (a) Genetic conservation value (for instance, if the wild ancestor is extinct), (b) the niche occupancy criterion and, finally, (c) a cultural criterion. We propose a detailed analysis of feral populations under scrutiny, supporting control measures when necessary, but also allowing for international protection at the same level as wild animals for feral taxa of special concern. Feral taxa, which are already in the focus of conservation efforts, and should be awarded extended recognition and protection, mainly include ancient lineages with relevant genetic or cultural importance.