What characteristic was ruthlessly culled by island hunters to maintain the breed's lineage on Ibiza?

Answer

Any dog that lacked the necessary speed, agility, or instinct.

The harsh island environment acted as a natural selection filter; hunters maintained only the keenest and strongest hunters, ruthlessly culling those lacking essential performance traits.

What characteristic was ruthlessly culled by island hunters to maintain the breed's lineage on Ibiza?
Dogbreedhoundprimitive