I get the impression most walruses are really much too large to keep as a pet. Unless you had a gigantic room to keep it in. But what if you could find a small, dwarf walrus - would it be possible to keep it as a pet?
I assume you can’t just go into the wild and grab a wild walrus and bring him home. Are there legal channels you could go through to legitimately obtain a walrus - outside of being a licensed wildlife researcher?
Walruses probably have to stay below a certain temperature to survive. If someone were rich enough that he could build a giant freezer, and use this as the walrus habitat, could he pull it off? I mean, zoos can build walrus habitats (and polar bear enclosures) so the technology is there to accomplish it. It’s just a question of having the money.