The Killer Mouse (Onychomys leucogaster) howls! Postcard

The Killer Mouse ((Onychomys leucogaster). Smithsonian102910 023.jpg. "Its behaviour is rather distinct from other mice. It is a carnivorous rodent, dining on insects (such as grasshoppers), worms, scorpions, snakes, and even other mice. It also stalks its prey in the manner of a cat, sneaking up quietly, and defends its territory by "howling" like a small wolf. The grasshopper mouse is known to be immune to various venoms released by its prey (scorpions, snakes, etc.).[2] [...] Very territorial, their average territory size may equal their home range size of about 28 acres. Their aggressive nature extends beyond their hunting habits, and when held in captivity with other mice, they will often kill and eat those other mice." http://en.wikipedia.org/wiki/Grasshopper_mouse