Eight years after it was first revealed to the public, the uncanny gait of Boston Dynamics’ quadrupedal robots is still unsettling. But a new video, released by the firm on Monday, shows the company’s flagship robot, the SpotMini, crossing a new threshold – literally – as it demonstrates that it can open doors.

The video depicts a SpotMini, a four-legged yellow machine that stands about a metre high, flummoxed by a closed door before a second robot of the same type, equipped with a fifth limb extending from its back, arrives to save the day. The second bot turns the handle, pulls the door open and holds it for the first to walk through, then follows.

The actions may sound prosaic, but small touches betray the complexity of the programming. After the second SpotMini pulls the door slightly ajar, it hooks one foot behind it, holding it open while it moves to the side to provide more room to swing it the whole way. When the first SpotMini arrives at the door, the robot – which has no neck but an array of sensors placed where its shoulders would be – leans back to peer at the doorhandle in a movement more fitting for a kennel than a robotics firm.

SpotMini is a miniaturised version of the robot that Boston Dynamics built its name on: BigDog, a robotic pack-horse originally designed for the US army. That avenue of commerce was shut down in 2015 when the military rejected the machine, complaining it was too noisy. “As marines were using it, there was the challenge of seeing the potential possibility because of the limitations of the robot itself,” a spokesman for the US marine said at the time. “They took it as it was: a loud robot that’s going to give away their position.”

Boston Dynamics is owned by the Asian conglomerate SoftBank, an enormous multinational that has been on an acquisition spree in recent years (it also owns the chip designer Arm Holdings, a majority of the US telco Spring, and has substantial stakes in Uber, Nvidia, Slack and WeWork). Until 2017, however, the company was owned by Google, later Alphabet, which had acquired it in 2013.

The two companies were always an uneasy fit. Boston Dynamics was bought as part of a hiring spree spearheaded by the Android co-founder Andy Rubin, who was leading Google’s internal robotics initiative at the time. But shortly after the acquisition Rubin departed to form a new smartphone company, Essential, and Boston Dynamics was left rudderless within the wider firm.

Facebook Twitter Pinterest The SpotMini has no neck but an array of sensors placed where its shoulders would be. Photograph: Boston Dynamics

According to leaked conversations published by Bloomberg, tensions rose to a head in 2015. That November, minutes from an internal meeting were accidentally posted to a Google-wide messageboard. They showed Boston Dynamics – still based in Boston, far from Alphabet’s Silicon Valley headquarters – being told that Alphabet was no longer happy to spend resources on the company’s long-term research. “There’s some timeframe that we need to be generating an amount of revenue that covers expenses and [that] needs to be a few years,” Rubin’s replacement, Jonathan Rosenberg, had said.

The founder of Boston Dynamics, Marc Raibert, responded: “I firmly believe the only way to get to a product is through the work we are doing in Boston. [I] don’t think we are the pie-in-the-sky guys as much as everyone thinks we are.”

Four months later, the schism widened after the release of a video demonstrating another Boston Dynamics robot, Atlas. In yet more emails accidentally published to the entire firm, a public relations staffer asked to “distance” Alphabet from the video, noting that “We’re also starting to see some negative threads about it being terrifying, ready to take humans’ jobs … We don’t want to answer most of the Qs it triggers.”