Sexy animal costumes are a great way let the wearer mix cute and cudlly with sexy and seductive.
Animal costumes reach something primal in us. Animals and people (yes, I know we're animals too) have the same basic needs - sustinance, safety, and procreation. Dressing like animals gives us license to act like animals.
Anyone dressed in a sexy animal costume can attest that their costume was the source of lots of attention and a number of sexy puns. Animal costumes often have great accessories like fur, wings, and floppy ears.