The bitcoin world kicked into high gear Friday as the US government began auctioning some of the virtual currency seized in an FBI investigation of dark Web bazaar Silk Road.

The US Marshals Service auction was taking place until 2200 GMT for 29,000 bitcoins -- about $17 million at current rates, although bitcoin values have been highly volatile.

Bidders had to register last week with a deposit of $200,000 -- in cash only from a bank transfer. Winners are to be notified Monday.

US authorities have another wallet of over 144,000 bitcoins which is not currently up for sale, which makes Washington likely the largest holder of the controversial cryptocurrency.

Bitcoins, according to backers, allow for an efficient and anonymous way to store and transfer funds online, but some governments contend the lack of regulation creates huge risks, and that virtual currencies are often linked to money laundering and organized crime.

The digital wallets were seized by the FBI in its investigation of Silk Road, an online black market for drugs, hacker tools and other illegal goods and services.

Bitcoins were created by a computer programmer in a way that allowed only limited amounts to be created. Whether they represent a currency is debated, but they are not backed by any central bank or government.

Bitcoin Shop, a virtual currency marketplace, announced that it would be bidding for the government-held coins.

"We believe in the future of virtual currencies and have made a strategic decision to participate in this unprecedented opportunity by wiring the deposit and submitting a registration application to the USMS," said chief executive Charles Allen.

Mark Williams, a Boston University finance lecturer and critic of virtual currencies, said the US is simply trying to unload its holdings.

"This auction doesn't validate bitcoin but simply demonstrated that the US government is anxious to get out before prices drop again," he said.

"The US Marshals Service (USMS) has over 29,000 reasons to sell by private auction and sell now."

Hippos of former drug lord Pablo Escobar pose environmental problem
Puerto Triunfo, Colombia (UPI) Jun 26, 2013 - Infamous drug lord Pablor Escobar built a zoo for his son in the 1980s. Roaming the acreage of his ranch, Hacienda Napoles, in Colombia's Puerto Triunfo -- 200 miles northwest of the capital, Bogotá -- were several elephants, giraffes, and four hippos.

When the drug lord died in 1993, the elephants and giraffes found their way into several Colombian zoos. But more than two decades after Escobar was shot dead by Colombian National Police, the hippos still roam free. Only now, there are more than four.

Escobar's ranch, after years of neglect, was repurposed as a park, with local environmental authorities taking responsibility for the upkeep. The hippos have apparently thriven -- maybe a little too much. Officials estimate that there are some 50 or 60 hippos in the park.

But locals say they've expanded beyond the zoo walls.

"They found a creature in a river that they had never seen before, with small ears and a really big mouth," said Carlos Valderrama, a conservationist with the local group Webconserva. "The fishermen, they were all saying, 'How come there's a hippo here?'" he told the BBC. "We started asking around and of course they were all coming from Hacienda Napoles. Everything happened because of the whim of a villain."

Valderrama and others say the expanding hippo population -- as so many other invasive species do -- threatens the area's biodiversity.

As the hippos -- their lazy, pampered lives buoyed by the slow moving Magdalena River and an ideal climate devoid of drought -- continue to breed, the problem gets worse and worse. And authorities aren't sure what to do.

Some suggest rounding up all the loose hippos and building a park with suitable fences. That would cost some $500,000, a half-million that environmentalists say should be spent to protect native species. Others say the males should be euthanized.

The hippos aren't just a threat to biodiversity, but a threat to Colombian people. Hippos are dangerous animals, killing between 100 and 200 people every year. And while some zoos in the area have adopted the hippo pups, the adults remain free -- some of them lurking in public.

The conundrum at least has one person amused. For Mexican novelist Juan Pablo Villalobos, the hippos are a ripe metaphor.

"It's like a sign of what's happened in Colombia in the last 20 years," he told the BBC. "And this past is still present, and Colombians maybe don't know how to deal with this memory, with Pablo Escobar's heritage."

"All those contradictions are still alive there," Villalobos added, "and I think now in the most absurd way -- in hippos reproducing in a river."