In the order of carnivorous animals, I think the worst criminals are found in the Marten Family (_Mustelidae_); and if there is a more murderous villain than the mink, I have yet to find him out. The mink is a midnight assassin, who loves slaughter for the joy of murder. The wolverine, the marten, mink and weasel are all courageous, savage and merciless. To the wolverine Western trappers accord the evil distinction of being a veritable imp of darkness on four legs. To them he is the arch-fiend, beyond which animal cunning and depravity cannot go. Excepting the profane history of the pickings and stealings of this "mountain devil" as recorded by suffering trappers, I know little of it; but if its instincts are not supremely murderous, its reputation is no index of its character. The mink, however, is a creature that we know and fear. Along the rocky shores of the Bronx River, even in the Zoological Park, it perversely persisted long after our park-building began. In spite of traps, guns, and poison, and the killing of from three to five annually in our Park, _Putorius vison_ would not give up. With us, the only creatures that practiced wholesale and unnecessary murder were minks and dogs. The former killed our birds, and during one awful period when a certain fence was being rebuilt, the latter destroyed several deer. A mink once visited an open-air yard containing twenty-two pinioned laughing gulls, and during that _noche triste_ killed all of those ill-fated birds. It did not devour even one, and it sucked the blood of only two or three. On another tragic occasion a mink slaughtered an entire flock of fifteen gulls; but its joy of killing was short-lived, for it was quickly caught and clubbed to death. A miserable little weasel killed three fine brant geese, purely for the love of murder; and then he departed this life by the powder-and-lead route. All the year round captive buffalo bulls are given to fighting, and for one bull to injure or kill another is an occurrence all too common. Even in the great twenty-seven thousand acre reserve of the Corbin Blue Mountain Forest Association, fatal fights sometimes occur. It was left to a large bull named Black Beauty, in our Zoological Park herd, to reveal the disagreeable fact that under certain circumstances a buffalo may become a cunning and deliberate assassin. In the spring of 1904, a new buffalo bull, named Apache, was added to the portion of our herd which up to that time had been dominated by Black Beauty. We expected the usual head-to-head battle for supremacy, succeeded by a period of peace and quiet. It is the law of the herd that after every contest for supremacy the vanquished bull shall accept the situation philosophically, and thereafter keep his place.