The absence of snow on the top of picturesque Mount Fuji in Japan was earlier attributed to global warming, but now seismologists think it may be because the volcano is heating up and may be getting ready to erupt.
The famous snow-capped mountain currently has no snow on top, despite record snowfalls in the region. Seismologists think it could erupt at any moment. Mount Fuji erupts about once every 300 years and it's been about that long since its last eruption.
Fuji is only 60 miles from Tokyo and when it last erupted, in 1707, tons of ash rained down on the city. Tokyo was a much smaller city in those days, but now it contains millions of people who might have to be evacuated if Fuji erupts again.
Birds, frogs and insects must sense that something is wrong, since they've abandoned the area. It's long been known that animals sense earthquakes and volcanic eruptions long before humans do.