I think it is fruitful and meaningful to take a descriptive approach to ethics. From a descriptive perspective, ethics is largely about reciprocity. people feel a high degree of ethical obligation towards those closest to them, less obligation towards strangers they perceive as "in-group" and none or very little towards strangers from various out-groups. This is why people frequently to donate a kidney to a family member but ignore starving migrants. People naturally also have a justified expectation, that the obligation they themselves feel towards their loved ones, is matched by an ethical right to support the other way.

The descriptive approach to ethics is a necessary starting point for discussions about ethics, as there is no indication that people can be convinced to act based on any of the more theoretical approaches to ethics (deontology, utilitarianism, etc.).

It is hard to see how to get from mutual commitment to animal rights. In the descriptive approach, it is not difficult to explain why the senile and brain-damaged have rights, but that is impossible if cognitive abilities is taken to be the foundation of rights: I risk becoming senile and brain-damaged myself, and in that situation I wouldt still want help; I am consequently obliged to render the same assistance. On the other hand, it is difficult to see how the same contract-like relationship can arise in the relationship with an elephant. Animals can have protection to the extent that they are someone's property, they cannot enter into an ethical relationship with humans because such relationships are always based on solidarity. Pets may be an exception, but not because they have "rights", pets are also "part of the family" and given priority above human members of out-groups.