Meet Amazon's newest holiday workers, the Kiva robots.
At the online retailer's fulfillment center in Tracy, Calif., more than 3,000 of the squat, brightly colored robots cruise the warehouse floor. Workers who once walked (and ran) the warehouse aisles picking up items as orders came in now stay on platforms waiting for the robots to fetch and deliver products to them.
"The little orange robot goes out and picks the right pod of inventory and brings it back just at the right time for the person to pick the item out to go in that customers shipment," David Clark, a senior vice president of worldwide operations and customer service for Amazon, told CNET.com's Kara Tsuboi.
Amazon employee Rejinaldo Rosales said the new system allows him to do in minutes what used to take hours.
"We don't socialize as much, but it's more efficient," Rosales said as the bots zipped around behind him on the eve of Cyber Monday, when Amazon showed off its latest generation of Kiva robots to a group of journalists.
The 320-pound robots can lift up to 750 pounds and are equipped with motion sensors to detect objects in their way. Looking a little like souped-up Roombas, the robots travel between three and four miles per hour.
Amazon said the robot's small footprint allows it to squeeze 50 percent more inventory into the warehouse -- an advantage on days like Cyber Monday, which is its biggest sales day of the year.
Customers ordered 426 items every second on Cyber Monday or more than 36.8 million items globally, according to Amazon.
Amazon expects that number to go up this year but wouldn't say by how much. Industry researcher ChannelAdvisor reported that Amazon's holiday sales were already up by 24 percent on Black Friday and up 45 percent on Saturday.
As the Kiva robots speed up the pace of Amazon's warehouses, they raise a troubling question for workers: How much of what a human does can be done by a machine instead? The automotive manufacturing industry already knows the answer, as do various technology makers. Foxconn, one of the world's largest electronics manufacturers and a key supplier for Apple, was reported to be replacing workers with robots a couple years ago. And take a ride across San Francisco's famous Golden Gate Bridge and there won't be a toll taker in sight -- the process is entirely automated.
The trend doesn't appear to be stopping, and experts say robots will take over half of all human jobs within 10 to 20 years. In a Pew Report in August, a vast majority of people surveyed said they expect robots to "permeate wide segments of daily life by 2025, with huge implications for a range of industries such as health care, transport and logistics, customer service and home maintenance."
So far, Amazon said it hasn't eliminated any jobs with the introduction of Kiva. In fact, the company says it's hired more people in that time. Amazon wouldn't say how many jobs it's added after incorporating Kiva, but overall it's hired 61,110 employees since 2011, the year before it bought Kiva. That's roughly doubling its employee base over the past two years, though the company saw a decline in that growth last year.
It did say the robots, introduced in 10 of Amazon's 50 fulfillment centers in the United States, have improved efficiency by 20 percent.
"Our focus on automation is about helping people do their job not replacing people," Clark said.