Authorities in Japan say an outage at Fukushima power station may have been caused by a rat.
Investigators at the nuclear plant believe the rodent may have been to blame for short-circuiting a switchboard, triggering a power cut. It took engineers over 30 hours to repair the damage.
They said they found burn marks inside the device and a 15cm animal nearby.
On Monday the outage caused the cooling systems for spent fuel rods at three reactors to shut down, though the cooling of the reactors themselves were not affected.
In March 2011 a huge earthquake and subsequent tsunami struck the plant causing meltdowns and it was brought back under control in December of that year.
This was the first time that so many electrical systems have been affected at the same time since then.