To take a more familiar case, it is only when the animal is in the presence of his own sex, and his intentions are the reverse of friendly, that the human understanding arrives at the vocal compass of domestic tom-cats. They then sing melancholy part-songs, out of all time and tune: we call them "cats' concerts." But if you will listen to them, and not disturb them either by laughter or missiles (as your humour may take you), you will observe that each cat is "singing" its very best. Very often no scrimmage results after the music is over, but each cat, satisfied with its exhibition of its upper register, goes its way. If, while listening, you can also see the cats while they are singing, you can have no more doubt as to their own opinion of their performances than when watching a blackbird. Female cats cannot sing. That fine voice is an ornament of the male sex alone, and whenever one male meets another--none of the other sex being present--they at once (if sudden conflict, giving no time for a "glee," does not supervene) fall to singing, each pitting his "g" against the other's. You may any day see two such encounterers, having sung their songs, relapse into placid indifference to each other's presence, just as blackbirds do, and depart harmlessly each about his own duties. [Illustration: "_As man's familiar guests_"] Lions sing much as blackbirds do. Morning and evening they get on to an eminence and lift up their voices, informing all the other lions in their parish, and the continents adjoining, that they are going to bed or have just got up, and that they do not intend to stand any nonsense; that that particular eminence is their own, and no other lion in Lybia or thereabouts will be tolerated in its vicinity. If, while one is roaring, there should come rumbling along on the wind the voice of another, the vocal duet is prolonged; but when the rites have been duly performed, "matin-song and vespers eke," they go about the business of the day or the night, as the case may be, without further ado.