⚡A quadruped robot named RAIBO2 completed a marathon on a single battery charge.

What it means

RAIBO2 is a four-legged robot developed by KAIST and the startup Lion Robotics. The paper reports that it completed the full 42.195 km Sangju Dried Persimmon Marathon in 4 hours, 19 minutes, and 52 seconds on a single battery charge, with no battery swap. The result is presented as a benchmark for energy-efficient legged locomotion, quantified by a very low Total Cost of Transport.

Accuracy & sourcesSourced

The claim is directly supported by the peer-reviewed Nature paper (doi:10.1038/s41586-026-11102-5) from KAIST and Lion Robotics, and the news coverage closely matches the paper's reported figures: 42.195 km, 4:19:52, and single-charge completion. As a primary source, the paper is the origin of the claim, though it is the authors' own experimental result rather than an independently audited race record.

How new

The Nature publication is current (September 2026 coverage), while the marathon itself took place in November 2024; so this is newly published research about an earlier event.

Go deeper

• Scientific American — first to publish