This species preys on ground and rock squirrels, which by six weeks of age develop a natural resistance to withstand a full envenomation, suggests research at the University of California, Davis.

• 北太平洋响尾蛇可捕食地面和岩石间的松鼠，不过这种松鼠在六周大时，就可自然发育出抗毒机制。