The anonymous poem "Rainbow Bridge" does not specifically mention dogs. The speaker in the poem speaks in second person and refers to the deceased pet as a "pet," "animal" and "special friend." No specific type of animal is mentioned, making the poem applicable to any pet.
The anonymous poet who wrote "Rainbow Bridge" was careful not to include any specific details about the pet that the addressee of the poem is reunited with by the end of the poem. The addressee simply caresses "the head" and looks "into the trusting eyes" of the pet. Specific characteristics, such as fur and paws, are not mentioned. Because the poem is free verse, people can easily tailor it to describe a specific type of pet without disrupting the flow.