From the Universal Translator page on Memory Alpha:
In 2267, Captain Kirk and Commander Spock of the USS Enterprise modified one to communicate with the alien known as the Companion in the Gamma Canaris region. Responding to Zefram Cochrane's question about the theory of operation, Kirk explained that there are certain universal ideas and concepts common to all intelligent life, and that the translator compared the frequencies of brainwave patterns, selected those ideas it recognized, and provided the necessary grammar. Kirk further explained that the device spoke with a voice, or the approximation of one, that corresponded to the identity concepts it recognized. The Companion was revealed to be female because the universal translator detected this facet of its identity from its brainwave patterns, and assigned it a female voice.
Now, see many animals on Earth (ofcourse, excluding humans): They aren't completely dumb. They live in colonies. They hunt in group with great coordination. Some pets even responds to their master. etc.. etc.. They are little intelligent without doubt. Can their brainwave patterns be used to communicate with them?
I have never encountered (or, not in my mind) anyone trying to communicate with animals. Is it possible? Have such thing been mentioned in the canon (saying, possible or impossible)? Is there a certain intelligence level which is required for universal translator to work?