The pictures are really simple and well-done, the story is in Japanese and English, something I rarely see in Japanese kids' books, and it's all about the wonders of the animal world. And it's only 900 yen, though I haven't looked into international shipping.
[9Brand also makes bags that look slightly like animals, at least in the photos; and these incredible "plush toy block sets," called the M.O.C system. It's sort of a soft Mr Potatohead with button-on parts instead of pegs&holes. I was going to rave about them first, but then I worried that the little legs and fins and stuff might be too small for a kid in the gnawing stage. Either way, the cat's out of the bag now.]
Atama wa Dotchi?/Which is your head? by Seto Keita, 900 yen [9brand.com via jeansnow]