Stumped by a ban designed to save elephants from extinction, Hong Kong's master carvers turned to a long dead species that left thousands of tonnes of frozen ivory in Siberian mass graves.
Mammoth tusks, intricately carved to depict anything from devotional Buddhist scenes and teeming wildlife to bizarre erotic fantasies, now make up most of the ivory for sale in the city.
The international trade in elephant ivory, with rare exceptions, has been outlawed since 1989 after populations of the African giants dropped from the millions in the mid-20th century to some 600,000 by the end of the 1980s.
The ban left hundreds of traditional carvers in the south China region facing an uncertain future, until they turned to a global stock of ancient tusks buried mostly in Siberia, but also in Europe and north America.
"I tried wood, stone and hippo teeth as well as mammoth tusks. It was six years after the ban that I started to focus on mammoth ivory," master carver Chu Chung Shing of Prestige Crafts told AFP.
But it took time to persuade connoisseurs to adopt a taste for the body parts of an extinct species.
"While elephant ivory was widely appreciated, mammoth tusk didn't have a similar following. The challenge was to educate people to the unique characteristics and value of mammoth ivory," he recalled.
Today Chu employs 160 carvers in mainland China, and inside his shop on Hong Kong's renowned Hollywood Road antique strip finely sculptured carvings up to 3.5 metres (11 feet) long, sell for up to a million US dollars.
A few doors down, proprietor Amy Wong displays a spectacular 380,000 dollar carved tusk depicting rainforest beasts in her window display at Cho's Art Crafts.
She turned to mammoth ivory 10 years ago and now employs 90 carvers across the border in mainland China, she told AFP.
Last year Hong Kong customs cleared 21 tonnes of mammoth ivory, on top of the 70 tonnes cleared in the two previous years, according to official data.
More than ninety-percent of it came from Russia's arctic tundra, and most of it was aged at 10,000 to 40,000 years old, according to information provided by dealers.
While there is an argument that the availability of the tusks of the already extinct species eases demand for illegal elephant ivory, there remains a concern that the legitimate trade could mask contraband.
"The two types of ivory are relatively easy to tell apart, but you need to know how to do so -- it's to do with the pattern of Schreger lines in the ivory," Richard Thomas of wildlife trade monitoring network TRAFFIC told AFP, referring to grain patterns visible in a cross section.
"Recognising this as a potential issue, TRAFFIC first published information aimed at enforcement officers on how to tell ivory from mammoth and elephant sources apart in 1991," he said.
So far Hong Kong border checks have left no record of elephant ivory entering the territory masked as mammoth products, a customs official told AFP.
Frontline officers in Hong Kong are well trained to detect suspicious consignments, she said.
"In case of doubt customs officers will refer the case to the Agriculture, Fisheries and Conservation Department to follow up."
Regardless of the safeguards, would-be elephant ivory buyers still look to mammoth traders as a potential source.
"We still have many customers asking for elephant ivory. There is definitely a market for that," said Mike Lau, manager of Cho's.
Another concern is that scientific information is being lost to the commercial trade.
"Mammoth ivory is absolutely a non-renewable resource, and it is absolutely being depleted, in part, by the commercial trade," University of Michigan mammoth expert Dan Fisher told AFP.
"A complete tusk contains a record of the whole life, much as a tree trunk contains a record of the whole life of a tree," he said.
Tusks can reveal the sex, age, season of death, and diet of individuals, as well as environmental conditions such as temperature, precipitation and yearly changes, according to Fisher.
"This provides a powerful source of data on earth history and ecosystem history. We can use this information in turn to address questions about changes in climate and biodiversity," he said.
But carver Chu believes that the commercial trade can co-exist with scientific research.
"The commercial trade actually draws more attention to mammoth tusks, and the craftsmanship helps to increase their value. It also brings more investment for archaeologists and explorers," he said, referring to Russian regulations that offset a proportion of commercial profits for scientific research.
Fisher says there are no clear estimates of how soon the world's stock of buried ivory would disappear.
"In the end there are so many unknowns that I think there is considerable uncertainty in any estimate. I would say the window of time left is greater than ten years, but how much greater I can’t say."
Explore further: WWF urges Romania, Bulgaria to protect wild sturgeon