On February 28, 2007, the parliament of the Balearic Islands, an autonomous community of Spain, passed the world's first legislation that would effectively grant legal personhood rights to all great apes. The act sent ripples out of the region and across Spain, producing public support for the rights of great apes. On June 25, 2008 a parliamentary committee set forth resolutions urging Spain to grant the primates the rights to life and liberty. If approved "it will ban harmful experiments on apes and make keeping them for circuses, television commercials, or filming illegal under Spain's penal code."
These precedents followed years of European legal efforts. In 1992, Switzerland amended its constitution to recognize animals as beings and not things. However, in 1999 the Swiss constitution was completely rewritten. A decade later, Germany guaranteed rights to animals in a 2002 amendment to its constitution, becoming the first European Union member to do so.
New Zealand created specific legal protections for five great ape species in 1999. The use of any gorilla, chimpanzee, bonobo, or orangutan in research, testing or teaching being limited to only those activities intended to benefit the animal subject or its species. A New Zealand animal protection group later argued the restrictions conferred weak legal rights.
Well-known advocates include primatologist Jane Goodall, who was appointed a goodwill ambassador for the United Nations to fight the bushmeat trade and end ape extinction; Richard Dawkins, former Professor for the Public Understanding of Science at Oxford University; Peter Singer, professor of philosophy at Princeton University; and attorney and former Harvard professor Steven Wise, founder and president of the Nonhuman Rights Project (NhRP), whose aim is to work through U.S. common law on a state-by-state basis to achieve recognition of legal personhood for great apes and other self-aware, autonomous nonhuman animals; all advocate for great ape personhood.
In December 2013, the NhRP filed three lawsuits on behalf of four chimpanzees being held in captivity in New York State, arguing that they should be recognized as legal persons with the fundamental right to bodily liberty (i.e. not to be held in captivity) and that they are entitled to common law writs of habeas corpus and should be immediately freed and moved to sanctuaries. All three petitions for writs of habeas corpus were denied, allowing for the right to appeal. The NhRP is in the process of appealing all three decisions.
Goodall's longitudinal studies revealed the social and family life of chimps to be very similar to that of human beings in some respects. She herself calls them individuals, and says they relate to her as an individual member of the clan. Laboratory studies of ape language ability began to reveal other human traits, as did genetics, and eventually three of the great apes were reclassified as hominids.
Other studies, such as one done by Beran & Evans, indicate other qualities that humans share with non-human primates, namely the ability to self-control. In order for chimpanzees to control their impulsivity, they use self-distraction techniques similar to those that are used by children. Great apes also exhibited ability to plan as well as project "oneself into the future", known as the process of mental time travel. Such complicated tasks require self-awareness, which great apes appear to possess: "the capacity that contribute to the ability to delay gratification, since a self-aware individual may be able to imagine future states of the self".
This, alongside the increasing risk of great ape extinction, had led the animal rights movement to put pressure on nations to recognize apes as having limited rights and being legal "persons." In response, the United Kingdom introduced a ban on research using great apes, although testing on other primates has not been limited.
Writer and lecturer Thomas Rose makes the argument that granting legal rights afforded to humans to non-humans is nothing new. He points out that in the majority of the world, "corporations are recognized as legal persons and are granted many of the same rights humans enjoy, the right to sue, to vote and to freedom of speech." Dawn Prince-Hughes has written that great apes meet the commonly accepted standards for personhood: "self-awareness; comprehension of past, present, and future; the ability to understand complex rules and their consequences on emotional levels; the ability to choose to risk those consequences, a capacity for empathy, and the ability to think abstractly."
Gary Francione questions the concept of granting personhood on the basis of whether the animal in question is human-like (as some have argued for great apes), and clarifies that sentience is the sole characteristic an animal requires to have basic rights. Therefore, he asserts, other animals—including mice and rats—should also be granted such rights.
Depending on the precise wording of any proposed or adopted declaration, personhood for the Great Apes may raise questions concerning protections and obligations under national and international laws, such as: