how did skeet and nig show their love for thornton?

From the text:

Unlike Skeet, who was wont to shove her nose under Thornton’s hand and nudge and nudge till petted, or Nig, who would stalk up and rest his great head on Thornton’s knee, Buck was content to adore at a distance. He would lie by the hour, eager, alert, at Thornton’s feet, looking up into his face, dwelling upon it, studying it, following with keenest interest each fleeting expression, every movement or change of feature.