
Originally Posted by
Politesse
Can and canino are valid terms for the same animal in continental Spanish as well. Perro is preferred informally and in the colonias, but the latin-related term wasn't lost. Many think that perro began as some manner of onomatopeia, since it doesn't seem to have any equivalents in neighboring languages.
Curiously, in English exactly the same process happened to exactly the same word. "Dog" is preferred informally, but the Germanic-related term "hound" is still a valid term for the same animal, and "hound" is the Germanic cognate of Latin "canis", and nobody knows where "dog" came from, and onomatopeia has been proposed.