technically yes, Animals are never naked (except furless animals) but undressed. But we usually say naked to animals who have human properties but wear no clothes. That make it in my opinion also easier when a character wears only a few pieces of clothes (like Sonic or Coco Pommel). Technically, they are not undressed, but (at least for me) naked. And I usually use the term nude or naked when the most parts of a body are undressed. ; )