Complex sentence: Atractaspididae, Colubridae, Elapidae, and Viperidae--approximately 60% of all bites are caused by vipers alone, and in drier areas, such as sahels and savannas, the saw-scaled vipers inflict up to 90% of all bites.
Split into simpler sentences: Atractaspididae, Colubridae, Elapidae, and Viperidae--approximately 60% of all bites are caused by vipers alone. In drier regions of the continent, such as sahels and savannas, the saw-scaled vipers inflict up to 90% of all bites.