(CNN) One is an endangered monkey with a cheesy grin. The other is a wildlife photographer who had just stepped away from his camera.

The two are at the center of a federal lawsuit filed by PETA , which wants the crested black macaque to win the copyright of a selfie he snapped with the photographer's unattended camera.

But before we get to how an Indonesian monkey became the focus of a court case, let's recap:

Photographer David J. Slater was taking pictures of endangered crested macaques in Indonesia when he temporarily left his camera on his tripod.

Sure enough, the curious simians grabbed the camera and played with their new toy -- pushing the button and capturing hilarious selfies, including a now-famous one dubbed "Monkey Selfie" taken by a macaque named Naturo.

But now PETA -- People for the Ethical Treatment of Animals -- is suing on behalf of Naturo, claiming he is the author of his selfies.

The photos were taken in Indonesia, but PETA says a U.S. federal court in California has jurisdiction because the publisher of Slater's book "Wildlife Personalities" is based in that state.

"While the claim of authorship by species other than homo sapiens may be novel, 'authorship; under the Copyright Act, 17 U.S.C. § 101 et seq., is sufficiently broad so as to permit the protections of the law to extend to any original work, including those created by Naruto," PETA said in the suit filed in U.S. District Court in San Francisco.

Slater called the lawsuit ridiculous.

"I am obviously bemused at PETA's stunt but also angry as well as sad," Slater wrote on Facebook , adding that he has worked with the organization in the past.

"This makes animal welfare charities look bad which saddens me, deflecting away from the animals and onto stunts like this."

Wikimedia battle, too

While PETA claims the monkey has the copyright to the selfie, Wikimedia claims no one does.

And that has also driven Slater bananas.

Wikimedia, which hosts sites such as Wikipedia, has allowed the Monkey Selfie on its free-to-use website.

Slater has asked Wikimedia to take the photo down. But Wikimedia said the photo is uncopyrightable because animals can't own copyrights -- so the selfie is a matter of public domain.

And so the professional photographer can't make money off photos shared in the public domain.

"Why do PETA and WIkimedia target Individuals when they want free rights to commercially exploitable images?" Slater wrote

So who wins?

All this monkey business raises two interesting legal questions: Can an animal even get a copyright of a selfie? And can a human get the copyright of a monkey's selfie?

CNN legal analyst Danny Cevallos said to qualify for copyright protection in the United States, a piece of work must meet three criteria:

• It must be fixed in a tangible medium. In this case, that would be a photograph.

• It must be original. "Overall, originality is a low threshold, and probably satisfied by the macaque's selfie," Cevallos wrote . But there's a catch for animals such as Naturo. Namely:

• The work must have an "author." And in the United States, the term "authorship" implies that the work comes from human being, Cevallos said. "Materials produced solely by nature, by plants or by animals are not copyrightable," he said.

So if the monkey doesn't win copyright of the photo, can the human?

Not likely, Cevallos wrote.

"Because the monkey cannot create a copyrightable work, that work can never be copyrightable," he said.

"In the case of a monkey's selfie by itself, that photograph immediately and forever falls into the public domain, and can be used by anyone, without permission."