Chibi-Robo .dat format (Gamecube)

With some help, i was able to extract the main file of "Chibi-Robo! Plug into Adventure!" for the Gamecube. However, all the files are in .dat format, which suggests this is some kind of archive, containg the models and textures. I read some stuff about Smash Bros. also using .dat format, but i am not sure if they are the same. Are there any tools to extract/convert these files (except hex editors, i can't work with them)? Below are some file samples, if anyone wants to take a look. Thanks.

Chibi-Robo Samples (edit: Link fixed)