Symbolism, Imagery, Allegory
It's a Dog-Eat-Dog World
There are dogs running all over this novel, and they actually play a pretty big role in propelling the plot. Good dog(s)!
These dogs figure in several major scenes and tend to be symbolically linked to Heathcliff. For example, when Lockwood tries to enter Wuthering Heights at the beginning of the novel, he finds not only several locked gates but also a pack of dogs preventing entry. "[T]wo hairy monsters" (3.101) with the names Gnasher and Wolf (eek!) attack Lockwood, and their lack of hospitality seems to reflect that of their master.
But Lockwood doesn't get the hint.
When Catherine and Heathcliff take their pivotal journey down to Thrushcross Grange, they share a glimpse of the sniveling Linton children fighting over a dog (6.37). When Catherine is bit by Skulker, one of the Lintons' dogs, she is compelled to stay at the Grange to recuperate, which changes her relationship with Heathcliff forever.
Finally, let's not forget Heathcliff's treatment of Isabella's springer, Fanny (finally, a likable dog name). As they elope from Thrushcross Grange, Heathcliff uses a handkerchief to hang the dog by his neck on a bridle hook—definitely some foreshadowing of the treatment his new bride will receive.