Dogs show up frequently throughout the novel, usually representing Christopher’s safety. This symbolism is particularly appropriate because dogs are often meant to protect the people around them. This symbol goes deeper than the symbol of the knife, however, representing not only physical, but also emotional safety.
The story begins with Christopher’s discovery of the dead dog Wellington. At this point, Christopher has no immediate worries for his safety, and in fact thinks himself responsible for others’ safety as he tries to find Wellington’s murderer. However, as he continues to investigate Wellington’s death, Christopher encounters emotional danger in the form of his mother’s letters and his father’s confession. After Ed tells Christopher that he killed Wellington, Christopher almost takes on dog-like qualities, barking whenever anyone bumps into him or frightens him. As he flees from his father’s physical and emotional violence, Christopher’s defense mechanisms become like those of the dog his father killed.
At the end of the novel, Ed gives Christopher another dog, Sandy, as a pet. This gesture helps to repair the relationship between father and son and helps Christopher feel safer around Ed. Ed may have killed a dog at the beginning of the book, but at the end he brings a new one into the story, and this symbolic gift seems to heal many of the wounds that have been inflicted over the course of the novel.
Additionally, Christopher sees dogs as symbols of safety in the context of his relationship with Mrs. Alexander. While always wary of her as a stranger, Christopher is more inclined to trust her because she has a dog, and he believes that people with dogs are generally nice.
Dogs Quotes in The Curious Incident of the Dog in the Night-Time
I want you to know that you can trust me. And... OK, maybe I don’t tell the truth all the time. God knows, I try, Christopher, God knows I do, but... Life is difficult, you know. It’s bloody hard telling the truth all the time. Sometimes it’s impossible. And I want you to know that I’m trying, I really am. And perhaps this is not a very good time to say this, and I know you’re not going to like it, but... You have to know that I am going to tell you the truth from now on. About everything. Because... if you don’t tell the truth now, then later on... later on it hurts even more. So.... I killed Wellington, Christopher.
I had to get out of the house. Father had murdered Wellington. That meant he could murder me, because I couldn’t trust him, even though he had said “Trust me,” because he had told a lie about a big thing.
...Father said, “Christopher, look... You have to learn to trust me... And I don’t care how long it takes... Because this is important. This is more important than anything else... Let’s call it a project....You have to spend more time with me. And I... I have to show you that you can trust me... And, um... I’ve got you a present. To show you that I really mean what I say. And to say sorry. And because... well, you’ll see what I mean.”
Then he got out of the armchair and he walked over to the kitchen door and opened it and there was a big cardboard box on the floor... and he took a little sandy-colored dog out.
Then he came back through and gave me the dog...
Then Father said, “Christopher, I would never, ever do anything to hurt you.”
And then, when I’ve done that, I am going to go to university in another town... And I can live in a flat with a garden and a proper toilet. And I can take Sandy and my books and my computer.
And then I will get a First Class Honors degree and I will become a scientist.
And I know I can do this because I went to London on my own, and because I solved the mystery of Who Killed Wellington? and I found my mother and I was brave and I wrote a book and that means I can do anything.