It is also the largest lake in Japan to freeze over completely in winter.

Rainbow trout, which are resistant to fairly acidic water, have been artificially introduced.

In 1951, the rare Hyalessa maculaticollis, commonly known as the Minminzemi cicada was discovered, and is now protected by the government.

Later, as daytime temperatures rise, with no room for the ice to expand, the resulting pressure causes ridges to form.

The peninsula has unique characteristics, with its hot springs making it one of the few places to see band-legged ground crickets (Nemobiinae) all year round.