How much more bizarre could a lawsuit get in which the plaintiff is a monkey who is suing a nature photographer and a publisher for copyright infringement?

Answer: a lot more.

People for the Ethical Treatment of Animals (PETA) and a primatologist named Antje Engelhardt are demanding that a San Francisco federal court declare a macaque monkey named Naruto the rights holder of a few famous selfies the monkey allegedly took in the Tangkoko Reserve on the island of Sulawesi, Indonesia in 2011. The monkey, the named plaintiff in the case, is suing a publisher and David Slater, the British nature photographer whose camera was swiped by an ape while the photographer was on a jungle shoot. Slater has published a book with the pictures the monkey took of himself, and the monkey is seeking damages for copyright infringement.

In its first defense papers (PDF) to the lawsuit PETA has brought on behalf of the monkey, San Francisco-based publisher Blurb asserts that the "US Constitution and the Copyright Act contemplate copyright protection only for humans."

"This is a copyright case filed on behalf of a monkey," Blurb attorney Angela Dunning wrote US District Judge William Orrick III on Friday.

But even assuming a monkey could own a copyright, PETA is suing on behalf of the wrong monkey, Dunning wrote. The lawsuit names Naruto, described as a six-year-old male crested macaque monkey. But in Slater's Wildlife Personalities, he describes the monkey as a female.

PETA, Blurb's defense maintains, "does not claim to have been present when the photographs were taken, and the Complaint contains no other allegations from which one could plausibly infer that Naruto is, in fact, the monkey in the photographs."

Because of that, Naruto has no right to sue, Dunning wrote. "And without any alleged basis to find that Naruto took the Monkey Selfies, there is certainly no basis to find that he suffered any injury giving rise to Article III standing."

The attorney for Slater, meanwhile, began its Friday court filing (PDF) with a joke.

"A monkey, an animal-rights organization, and a primatologist walk into federal court to sue for infringement of the monkey's claimed copyright. What seems like the setup for a punchline is really happening," attorney Andrew Dhuey wrote. He added that "monkey see, monkey sue is not good law..."

Dhuey's short briefing paper said that "The only pertinent fact in this case is that Plaintiff is a monkey suing for copyright infringement."

The litigation comes a year after regulators from the US Copyright Office agreed with Wikipedia's conclusion that a monkey's selfies cannot be copyrighted. The office said works "produced by nature, animals, or plants" cannot be granted that protection.

The suit, however, demands a San Francisco judge to not only grant the copyright to the monkey, but it wants an order permitting PETA to "administer and protect Naruto's rights in the Monkey Selfies on the condition that all proceeds from the sale, licensing, and other commercial uses of the Monkey Selfies, including Defendants' disgorged profits, be used solely for the benefit of Naruto, his family, and his community, including the preservation of their habitat..."

Slater, meanwhile, says he's been granted copyright protection in the UK for the selfies and maintains he should have that right in the US, too.