Researchers say that climate change killed off the woolly mammoth more than 4,000 years ago, but now it looks as if warmer weather is bringing them back - as prized symbols of wealth for the mainland's growing middle class.
The growing demand for mammoth ivory - dubbed by some ethical ivory because the material is sourced from an extinct species - is, in part, the result of a ban on the trading of elephant ivory imposed in 1989.
The ban was imposed by the Convention on International Trade in Endangered Species in wild fauna and flora (Cites) owing to high levels of poaching that were decimating elephant populations across Africa. The move meant more than 1,000 businesses in Hong Kong selling ivory had to apply for a licence to sell their remaining elephant ivory stocks in 1990.
Soon afterwards, many either closed down or shifted to selling mammoth ivory.
The process of sourcing mammoth ivory begins in Russia where, during their summer, thousands of locals flock to the tundra of northern Siberia.
As the ice thaws from June to September, the frozen graves of mammoths melt and the corpses of the long-extinct beasts rise to the surface.
The Russians, who must have permits to collect the dead animals, gather the tusks, which are then exported.
It is thought that the remains of up to 150 million woolly mammoths may be buried beneath the tundra.
While the annual collection of tusks has been going on for thousands of years, demand for mammoth ivory has risen steadily over the past decade, with Hong Kong as a major hub for the trade.
In 2000, about five tonnes of mammoth ivory, worth about HK$2.3 million, was imported from Russia. By 2007, this had risen to 46.2 tonnes with an estimated value of HK$60 million - the bulk of it imported from Russia. In the first eight months of this year, more than 22.6 tonnes of mammoth ivory had arrived in Hong Kong from Russia alone.
Other countries that export mammoth ivory to Hong Kong include the United States, Germany, Canada and Austria, but the amounts from these sources are insignificant.
Most of the raw tusks imported are re-exported to the mainland, where they are hand-carved. The ivory is then either brought back to Hong Kong, or sold to mainland buyers.
John Sellar, chief enforcement officer for Cites, does not believe the mammoth-ivory trade has reduced the demand for illegal elephant ivory.
'My gut reaction is that it hasn't [cut demand] because we still see serious levels of poaching in Africa,' he said from the Cites headquarters in Geneva, Switzerland.
'Some of the seizures that we see are very significant ... several tonnes in one shipment.'
Only last month, Hong Kong customs officers intercepted an illegal shipment of 1.5 tonnes of elephant ivory - worth HK$10.8 million - hidden under dried anchovies. It was the third seizure of its kind this year.
Mammoth ivory was an important part of the growing demand for ivory, Sellar said.
'There's undoubtedly been a resurgence in ivory and that goes along with the increased affluence in China,' he said. 'The role of mammoth ivory is no doubt significant because carvers in mainland China, Hong Kong and Taiwan did switch to it after the international ban on elephant ivory.'
Along Hollywood Road in Central, about a dozen shops sell mammoth ivory and a number of high-end shops trade exclusively in mammoth products, such as Cho's Arts Crafts, run by Amy Cho and her husband.
They import about 8 tonnes of mammoth ivory every year from Siberia and export it to their factory in Guangzhou.
Cho said prices for raw mammoth ivory had tripled in the past 10 years, with low-quality ivory costing about HK$1,000 per kilogram and the better-quality ivory as much as HK$6,000 per kilogram.
They have doubled their staff since 2000 and now employ 100 people, aged between 20 and 40, who design, carve and polish the ivory.
Previously, 70 per cent of the finished items would return to Hong Kong, but this proportion has fallen to 30 per cent in recent years because more of it remains on the mainland to meet local demand.
'The market here is slow now,' she said.
Depending on the size of a tusk and the intricacy of the design, a completed piece can take anywhere from six months to 18 months of work.
In the Chos' window display, one two-metre-long mammoth tusk, depicting dozens of animals, is valued at more than HK$3 million.
A few doors along Hollywood Road, the spacious showroom at L'Extreme Orient displays a 3.29 metre mammoth tusk, carved to represent the story of the Great Wall of China and valued at HK$10 million.
The store, established in 1983, switched from elephant ivory to mammoth ivory and imports raw tusks from Siberia before sending them to its factory in Hong Kong for carving.
'Demand for mammoth ivory has increased in the last few years with more and more buyers from mainland China,' said saleswoman Lilac Hui.
Further down the street, Vincent Chan works at his father's 30-year-old shop, True Arts and Curios. Its small area is filled from floor to ceiling with thousands of palm-sized trinkets in jade, porcelain, silver, bronze, wood and mammoth ivory.
'People like the ivory because it's good for investment,' Chan said.
'Mostly, people buy the animal carvings. Some like the erotic figures and some like the Japanese netsukes [carved button-like ornaments], which have two holes at the back for a necklace.'
The shop began selling mammoth ivory about 15 years ago, after the Cites ban on elephant ivory. A 10cm mammoth ivory figure will cost between HK$2,000 and HK$3,000, depending on its weight.
Meanwhile, old elephant ivory pieces acquired before the ban still sit on the shelves. 'I can't sell them because tourists can't export [elephant ivory]; only locals can buy it,'' Chan said.