Recently, the parliament in Spain passed a resolution granting legal rights to apes  —  specifically, life, liberty and freedom from physical and psychological torture.

Wild apes don’t live in Spain, but for those apes currently confined there in zoos, living conditions must be improved. Apes will no longer be made to perform in circuses or take part in medical experiments.

Behind this decision is a Seattle-based international organization called the Great Ape Project, which refers to humans, gorillas and orangutans as “members of the community of equals.” That description is inspired, in part, by the fact that humans are biologically very close to the great apes, sharing about 95 percent of their DNA. Re-searchers say that apes also demonstrate many human-like abilities, including creating complex communications and forming emotional bonds. Lesser apes, such as gibbons, were not included because the data suggesting their connections to humans is weaker.

The great apes were not quite equated to human adults; instead, it was suggested that they are similar, in emotional and intellectual capacity, to human children. As such, there is no movement afoot to grant them the right to vote, for example. The Spanish language suggests they are akin to “humans of limited capacity, such as children or those who are mentally incompetent and are afforded guardians or caretakers to represent their interests.”

Naturally, animal rights supporters are jubilant. Peter Singer, a Princeton University bioethics professor, animal liberation activist and GAP founder, said the decision was of “world historical significance.”

Some critics have wondered why, if the Spanish parliament deemed great apes insufficiently protected, it felt the need to go all the way to granting them rights rather than introducing stronger laws for their protection. The reason, they suggest, is that improving the treatment of great apes is not really the major impetus for this fight and this decision.

Supporters essentially admit as much. PETA founder Ingrid Newkirk called Spain’s action “a great start at breaking down the species barriers, under which humans are regarded as godlike and the rest of the animal kingdom, whether chimpanzees or clams, are treated like dirt.” Singer hopes that GAP could lay the groundwork for granting rights to all animals. Proponents hope this precedent will signal the beginning of the end of the species barrier. They are looking for the demise of the belief in human exceptionalism, which suggests that humans rightly have a special status in nature.

On the other hand, the arguments GAP has made on behalf of great apes seem to point to their own exceptional status; those descriptions can’t be easily applied to all other animals. Singer himself allows that species should be evaluated on a case-by-case basis, which is something we already do with many animal cruelty laws: The Humane Slaughter Act says a cow must be unconscious before slaughter, but that’s not the case for a chicken.

For apes, their cause will be the subject of continued debate, of course. Now Austrian animal rights supporters are fighting to have a particular chimp granted the legal status of a person. Courts have ruled against them, but they plan to appeal  —  to the European Court of Human Rights.