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

[Maciamo]

1) I think you should ask the Chinese about that.
2) Aren't you assuming a bit too much in the way of knowledge of biological classifications 3000 years ago? It's nice that we know this now, but I doubt the Chinese knew it when they were creating the characters.

Are you saying that a country that decided to drop half of its culture to adopt Western systems, sciences, and invented new kanji compound for them, a country that has imported so many linguistic terms from European languages, could not have changed the kanji for whale or just supress it and replace it by katakana or hiragana as has been done with other words. No, there was no will to do so because for the Japanese it isn't really a problem to associate whales with fish. After all, don't they all live in water ?

By the way, "tele" and "homo" in English are now considered words that are mere abbreviations of fuller words ("television" and "homosexual," respectively), and they depart from their original meanings as bound morphemes ("distant" and "same," respectively). They have both already combined with other elements with their new meanings: "televangelist" and "homophobe" are examples. While not exactly the same, the creation of kanji bears some similarity to this process, so it's not like Chinese or Japanese are the only ones to do this.

I would associate this more with the creation of new words from old kanji (e.g. 写真). The Japanese are masters in word combinations that completely depart from the originally meaning (e.g.リモコン) and mixing Japanese with foreign words to form new terms (e.g. カラオケ, from "空" and "orchestra"). But this has nothing to do with biological classification. You are arguing about purely linguistic formations.

By the way:
turtle -- ウミガメ
tortoise -- カメ
mouse -- ハツカネズミ
rat -- ネズミ
shrew -- トガリネズミ
vole -- ハタネズミの類・野ネズミ
whale -- クジラ
rorqual -- ナガス［イワシ］クジラ
orc (I assume you meant "orca") -- シャチ, and also the loan words キラー・ホェール and オルカ
Looks like they're pretty differentiated to me. In fact, not only that, but they look better organized as well. All of the rodents end in ネズミ, and two of the three whales end in クジラ.

You are good at confirming what I had just explained above with more detailed examples. Indeed, in Japanese, a "turtle" is a "sea tortoise", and the Muroidea (family of the mice, shews, voles, gerbils, rats, hamsters...) are just ネズミ, with an adjective differentiating them. The same is true for Cetacea, only roughly divided in クジラ (whale) and イルカ (dolphin), a bit like small children do in the West. I am suprised that English doesn't have a unique word for "sperm whale" (cachalot in French) or "roe deer" (chevreuil in French), or does not differentiate between owls with external ears (hibou in French) or no external ears (chouette in French) so imagine my disappointment with Japanese language, despite Japan having such a special relationship with whaling. Japanese language also lacked differentiation between weasel, skunk, mink, ermine, polecat, all commonly refered to as いたち, although the English words is sometimes used for スカンク (skunk) or ミンク (mink). You have to admit that even when an English word has been imported, most Japanese (especially if they do not speak English well) do not use these loan words. Likewise, I rarely heard the Japanese making a point in differentiating a mouse from a rat.