Do the Japanese really love nature more than all other people ?

[Maciamo]

Well, a pineapple isn't an apple, and I don't know what grapefruits have to do with grapes, and eggplants certainly aren't grown by planting eggs, nor do they sprout them, yet we use these words all the time.

Indeed, but eggplant is only American English (the proper British English word is aubergine). As for grapefruits, it is because they grow in clusters/bunches like grapes (such "bunches" are called "grappe" in French). But I never understood why English has chosen "grapefruit" rather than "pomelo", "pompelmo", "pamplemousse", "pompelmoes", "Pampelmuse" or something like that, like in other Western European languages. "Pamplemouse" would have been an easy English adaptation.

No, I said 魚 as a radical has a broader meaning. It also means "fish," though (see English "turtle" above).

So there is only one word for "fish" and for "species that live in the water". It still show a lack of scientific rigour.

Perhaps it would be better to say that there should also be the gloss "rodentia" there (or something like that) to give the impression that it's a scientific classification and not just rats and mice. As was written above, ハツカネズミ is "mouse" and ドブネズミ is "rat." As for whales, like I said, I didn't look into that one very deeply, but I see a pattern emerging.

The grey, big rats regarded as varmint are called ドブネズミ while the white ones used for tests/experiments are called ラット

Thanks for the update. I always thought, and according to my pocket Random House dictionary, they were 大鼠（おおねずみ）.

Isn't it incredible that one of the world's most common mammals, the rat, does not have a clear name in Japanese ? In some dictionary it is ドブネズミ ("gutter mouse/rodent"), in others it is just ネズミ ("mouse/rodent"), in others ラット (from English) and in others yet 大鼠 ("big mouse/rodent") ! None of them are unique words, only adjective + noun compounds, except if "nezumi" alone means "rat", in which case it cannot mean "mouse" or "rodent" without having a double usage again.