The similarities are so profound, according to some legal activists and scientists, that chimps should be recognized under the law as "non-human persons."
The same goes for elephants, orcas and even the African grey parrot, according to some legal interpretations making the rounds.
That would mean no more zoos, labs or being kept as pets.
They would have legal status similar to that of children — no longer "mere 'things,' which lack the capacity to possess any legal right," in the words of the Nonhuman Rights Project, a group that has recently been fighting in court to win the freedom of four chimps in New York state.
The NRP made headlines last month when a judge, seemingly in error, granted a writ of habeas corpus to two chimps the group has been trying to spring from a lab at Stony Brook University.
The writ — a legal bombshell that appeared to confer personhood on both animals — was quickly amended.
The judge crossed out the powerful legal phrase, but, however inadvertently, she seems to have set some wheels in motion. The case will be back in court on May 27.
The case is "probably the most progressive or advanced approach to dealing with this issue," says George Dvorsky, a Toronto-based science writer and ethicist. "The rubber has only hit the road in the last couple of years."
The U.S. is fertile ground for these sorts of legal arguments, legal experts say; New York in particular as the state is among those that, for example, allows pets to be the beneficiaries of trusts.
That gives them a legal leg up that animals don't enjoy everywhere.
Other jurisdictions, though, are moving in this direction as well.
Germany amended its constitution to grant animals certain rights in 2002, and the Balearic Islands, an autonomous region of Spain, granted personhood to great apes in 2007.
India's ministry of forests and environment opined in 2013 that dolphins and whales should be treated as non-human persons and, last year, a judge in Argentina appeared to grant personhood to an orangutan, though observers say the full interpretation of that case has yet to be worked out.
'Their status is evolving'
Nothing so dramatic has happened in Canada, but recent rulings could lay the groundwork for pro-personhood cases, according to B.C.-based animal rights lawyer Rebeka Breder.
"Courts across the country are starting to recognize, even though animals are technically property, that they're also something a little bit more than property," she says.
"They're somewhere between furniture and a person."
An Alberta court last year said pets are "not simply chattels" when it sided with a woman in a dispute with her condo board over her two cats.
"Animals might not yet have rights in the conventional sense ... but the very least that can be said is that their status is evolving," wrote judge W.S. Schlosser.
"Their status remains … a grey area, and a large one at that."
Schlosser's ruling, which was upheld on appeal, nodded to the earlier case of Lucy, the elephant at Edmonton's Valley Zoo that activists tried to relocate to a sanctuary in 2011.
A lower court turned the case away. But in a lengthy dissenting opinion, Chief Justice of Alberta Catherine Fraser appeared to acknowledge the changing legal attitudes towards animals.
She concluded that the activists and, by extension, Lucy were "entitled to their day in court."
Adapting and expanding
Fraser's dissent was "a glimmer of hope" says Camille Labchuk, director of legal advocacy for the group Animal Justice. She says she's optimistic Canada's courts will one day accommodate more daring arguments like those of the NRP.
"The beauty of common law is it's capable of adapting and expanding to new societal realities," Labchuk says.
But even ardent proponents agree the process will be slow and fraught with resistance from both courts and the public.
Breder notes that it took a long time, for example, before women won recognition as legal persons in Canada. But the law eventually "caught up with … the societal uproar," she says.
"I'm optimistic that the law here in Canada will get to the point that it recognizes animals, and especially certain kinds of animals, should be deserving of legal status."
"If we can do it for corporations" — which are persons under the law — "there's no reason why a sentient living being can't be considered a person."