Gestation period of African savanna elephants?
The African bush elephant and the African savannah elephant are the same species (i.e., they are just different names for Loxodonta africana). 

According to here and here, the African savanna/bush elephant (Loxodonta africana) has a gestation period of 22 months. 

The only other African species of elephant, the African forest elephant (*Loxodonta cyclotis), has a gestation period of 20 - 22 months (see here). Both Wikipedia and this source corroborate this higher expected range of 22 months, but with the latter source adding:


  from zoo data a gestation length averaging 660 days has been determined while the average in one wild population (Amboseli) was 656 days.


And for fun, click below for a video of an elephant fetus!