Complex sentence: Genets possess extremely long tails--typically over 1 to 1.5 times the length of their bodies--providing a highly effective counter-weight that enables them to easily maintain balance as they leap from tree limb to tree limb.
Split into simpler sentences: Genets possess extremely long tails, typically around one to one and a half times the length of their bodies. These longs tails provide a highly effective counter-weight that enables them to easily maintain balance as they leap from tree limb to tree limb.