And thus on Bentham's, Singer's, Rachel's analyses, crabs belong to the moral community. These creatures' pain is no less important than a human being's. Clearly crabs value "not feeling pain" by choosing to avoid it. Subjective experience of pain and memory of the negative experience of pain are present, according to this study.
Let us examine Justus Buchler's concept of ontological parity applied to the realm of value here. It is ignorance to say that value or importance is simply a "human construct," as crabs clearly find importance in avoiding pain - there is a basic value in it *for them* regardless of human judgement. As with any basic emotion experienced by animals, what makes creatures equal is the univocal fact of value (contrasts of positive and negative aesthetic value: whether through sensation or intensity) experienced by those creatures. In other words, a sense of value or importance makes for the subject of a life in the aesthetic contrasts of value felt by that life.
If Buchler's ordinal metaphysics is applied to animal ethics suddenly value theory and ecology take on new meanings.