This article is more than 2 years old.

December 1, 2014 This article is more than 2 years old.

Last year on Cyber Monday, consumers spent a then-record $2.29 billion shopping online. This year, sales are expected to hit $2.6 billion (pdf). How does a massive online retailer like Amazon handle all that volume?

Robots. Swarming, darting robots that give the company’s million-square foot warehouse the efficiency of an ant farm.

Amazon recently released footage from the inside of its latest robot-teeming fulfillment center. Watch:

The robots were built by Kiva Systems, a robotics company that Amazon bought in 2012. Amazon now has over 15,000 of the Kiva bots across 10 fulfillment centers, according to TechCrunch.

Amazon will still need 80,000 seasonal employees to handle tasks requiring dexterity, like packing a box.

But the company’s need for human workers may dissipate as robots get smarter and more nimble—and as more customers demand same-day delivery on their Tickle Me Elmos.