MySQL Schema Design: One Possible Values Between Multiple Columns
id, species_name, dominant_color, owner_id,  
type ENUM('mammal', 'bird', 'reptile', 'arachnid', ...),  
other_characteristics TEXT


Where other_characteristics has JSON in it.  You can add whatever you want there.

Other tips:  Do not blindly use (255); use some reasonable limit.  Once wingspan is in the JSON, you can get rid of the ridiculously precise DECIMAL(11,8).