In this paper, we discuss the bridging potential of “interspecies” solidarity between the often incommensurable ethics of care and justice. Indeed, we show that the Environmental Communication literature emphasizes feelings of care and compassion as vectors of responsibility taking for animals. But we also show that a growing field of Political Animal Rights suggest that such responsibility taking should instead be grounded in universalizable terms of justice. Our argument is that a dual conception of solidarity can bridge this divide: On the one hand, solidarity as a pre-political relation with animals and, on the other hand, as a political practice based on open public deliberation of universalizable claims to justice; that is, claims to justice advanced by human proxy representatives of vulnerable non-humans. Such a dual conception can both challenge and validate NGOs’ claims to “speak on behalf of animals” in policy following the Aarhus Convention, indeed underwriting the Convention by insights from internatural communication in solidarity as relation, and by subjecting it to rational scrutiny in mini-publics in solidary as practice.