There are more "cute" mascots per capita in Japan than anywhere else on the world by far. Last year a serious culling took place but still they continue to propagate. Among the latest is even one for the campaign to "promote" the cleanup of the nuclear meltdown at Fukushima.
To my mind such infantile mascots belong in the realm of the under 7's, but I seem to be in a minority. Its not surprising then that such mascots appear sometimes on the manhole and drain covers. The first is of one of the pair (male and female) of mascots for Sanda City in Hyogo. I believe it is based on the official city bird, the green pheasant.
The second depicts Ratochan, the official mascot of Oda City where Iwami Ginzan is located. It is based on the shell-candle miners used to take to light their work underground. The third is from Nakatsu. Kurokankun is based on Kuroda Kanbe, the samurai who built Nakatsu castle.
The fourth is Kintakun, the mascot of Kawanishi in Hyogo, and the final one is I think a cat in samurai helmet representing Hikone.