Log on to the world’s most popular social-media platform and type “tiger teeth” in the search bar.

Up pop photos of glistening white jaws torn from carcasses and various “closed groups” peddling parts of the great cats.

Click on one such group and a page appears with Chinese writing. Translated, it speaks of Oriental treasures, or Qizhen arts and crafts, alongside an odd assortment of ivory and endangered animal parts for sale. The going price for the ivory — tusks brutally hacked from elephants by poachers — is a cool $1,500 per pound.

Blood money at the ready, one more click brings you a step closer to acquiring the illicit ivory. You’re automatically asked a series of simple questions about preferences. Show the most basic knowledge and you’re welcomed as a new “member.” Next come live digital conversations, more detailed vetting and, if you pass the tests, blood-drenched deals.

Welcome to Facebook, home to one of the largest black markets for the illegal buying and selling of the parts of slaughtered endangered animals, whistleblowers say.

From high society in New York to the badlands of Mexico, buyers are secretly scrambling to snap up the globe’s dwindling supply of elephant tusks, rhino horns, bear claws, tiger skins and other prized wildlife products in an annual trade estimated at $23 billion, according to the UN and Interpol.

And in New York, one of the largest markets for illegal ivory sales in the US, deals are moving from smoky back rooms to “closed” Facebook groups.

“What’s happening is really scary and a very worrying phenomena,” said Iris Ho, the wildlife campaigns manager at Humane Society International. “It is now possible that sellers and buyers in New York can go online, set up a closed or secret group on Facebook and proceed with their transactions.”

Last year, law enforcement nabbed the owners of Metropolitan Fine Arts and Antiques in Midtown for illegally selling some $4.5 million in ivory from more than a dozen slaughtered elephants. One pair of tusks, among 126 ivory items, was selling for $200,000.

While Manhattan DA Cyrus Vance wouldn’t say if Facebook played a role in that case, he said his office is “monitoring social-media channels for evidence of illegal sales and trafficking.”

“The amount of wildlife being traded on closed and secret groups on Facebook is horrifying,” said a rep for whistleblowing Washington law firm Kohn, Kohn & Colapinto, which filed a federal complaint against Facebook last month. “We saw multiple products: rhino horn, bear claws, tiger skins, reptiles, and tons and tons of ivory. At a time when the world is losing 30,000 elephants a year to poachers, the amount of ivory sold on Facebook is particularly shocking.”

“Rhino horns are worth more than gold,” said Ho. “If you are buying it in Asia, after layers of middlemen, the retail price could go up to $60,000 per kilo, or higher.”

In the whistleblower complaint filed last month with the US Securities and Exchange Commission, Facebook is accused of knowingly profiting from this blood trade by selling and placing ads for consumer products on public and private pages managed by traffickers.

“We noticed, for example, how young men in Asia and Europe trolling Facebook for information on endangered species would see ads for American sneakers, or a UK premier club soccer team, showing up beside their Facebook news feeds based on their profile data,” said Gretchen Peters, executive director of the Center on Illicit Networks and Transnational Organized Crime, which has worked with investigators in the whistleblower complaint.

Facebook says they are working on the problem.

“Our Community Standards do not allow for poaching, the sale of wildlife, endangered species or their parts, and we immediately remove this material as soon as we are aware,” Facebook said in an official statement, saying it does not “allow ads around the sale of endangered animals.”

The Kohn firm said it uncovered more than a dozen networks on Facebook specializing in illegal sales, as well as traders in Vietnam and Laos who were literally making a killing by utilizing the social media platform.

The SEC declined to comment.