This article talks about therapy dogs and they do for victims of tragedy. Specifically, Golden Retrievers are trained and brought to situations where they are needed. Many children involved in the Sandy Hooke shooting would not talk about the experience, must less talk about anything at all. After being with the therapy dogs for a short period of time, that quickly changed. The kids began to open up, communicating with the dogs and counselors. The silence, and unconditional love these dogs have give much comfort to the victims. Studies have shown that petting a dog lowers blood pressure, reduces stress, and regulates breathing. It is unknown is dogs actually possess empathy, although many think they do due to their responses to emotions.
http://news.nationalgeographic.com/news/2012/12/121221-comfort-dogs-newtown-tragedy-animal-therapy/
Zoology 