Animal behavior specialist K.G. Lorenz in his book King Solomon's Ring describes the loyal dog as having eyes that "mark your coming and look brighter when you come."
動物行為學家勞倫茲在「所羅門王的指環」一書中對狗的忠誠有如下的描述：「你不在時將你苦思，你一出現就眼睛發亮。」