The serpentine bloodline has the ability Serpentfriend, which grants a viper familiar.
Serpentfriend (Ex) wrote:
At 3rd level, you can use speak with animals at will with reptilian animals (including various forms of dinosaurs, lizards, and other cold-blooded creatures), and you gain a viper familiar using your sorcerer level –2 as your effective wizard level.
If a serpentine sorcerer had the Improved Familiar feat, would it be applicable here? I know that it has to be a viper familiar, but the list of improved familiar options includes familiar, celestial/entropic/fiendish/resolute/etc. The minimum level for all of these templated familiars (except clockwork) is 3rd.Could the sorcerer take a viper familiar, and apply one of the templates to it?