The verses in Vayikra 11:4-6 gives 3 examples of different impure animals which don't have split hoofs, namely: the camel, the 'hyrax' (shafan) and the hare. An interesting thing I once noticed is that if you look at the Hebrew text you'll notice that when stating how each one doesn't have split hoofs the tense is different:
ד. אַךְ אֶת זֶה לֹא תֹאכְלוּ מִמַּעֲלֵי הַגֵּרָה וּמִמַּפְרִיסֵי הַפַּרְסָה אֶת הַגָּמָל כִּי מַעֲלֵה גֵרָה הוּא וּפַרְסָה אֵינֶנּוּ מַפְרִיס טָמֵא הוּא לָכֶם: ה. וְאֶת הַשָּׁפָן כִּי מַעֲלֵה גֵרָה הוּא וּפַרְסָה לֹא יַפְרִיס טָמֵא הוּא לָכֶם: ו. וְאֶת הָאַרְנֶבֶת כִּי מַעֲלַת גֵּרָה הִוא וּפַרְסָה לֹא הִפְרִיסָה טְמֵאָה הִוא לָכֶם:
The camel...does not have a [completely] cloven hoof (present tense)
The hyrax... will not have a [completely] cloven hoof (future)
The hare... didn't have a [completely] cloven hoof (past)
I looked in a Mikraot Gedolot but couldn't find anything about this diyuk. Anyone have any insight?