Mustela erminea, commonly recognized as the stoat or short-tailed weasel, is a widespread small carnivorous mammal. These agile predators are known for their slender bodies and hunting prowess. They navigate diverse environments with stealth and speed.
Appearance and Habitat
The stoat exhibits a slender body, short legs, and an elongated neck, with its head positioned notably forward from the shoulders. Its body is nearly cylindrical, without a prominent abdomen, and its circumference is a little more than half its length. Males are generally larger than females. A distinguishing feature is the black tip on its tail, which remains black year-round regardless of coat color.
A striking adaptation of the stoat is its seasonal coat change. In summer, its fur is typically chestnut-brown on the back and head, with a creamy white or yellowish-white underside. As winter approaches, the stoat molts its brown fur, replacing it with a dense, insulating white coat, a phenomenon known as ermine. This white coat provides effective camouflage in snowy environments.
Stoats have a wide distribution across the Northern Hemisphere, inhabiting much of North America, Europe, and Asia. Their presence extends from the Arctic Ocean and Greenland in the north to areas as far south as California and Spain. This species is highly adaptable, thriving in a variety of habitats including woodlands, grasslands, tundras, marshes, and even suburban areas like farmlands and orchards. While they prefer areas with good ground cover, they are also found in coastal regions and mountainous terrains up to 3,000 meters. Stoats were introduced to New Zealand in the late 19th century to control rabbit populations, but they subsequently became an invasive species, impacting native bird populations.
Diet and Adaptations
The stoat is primarily a carnivore, relying on a diet of small mammals. Their prey includes rodents such as mice, voles, and hamsters, as well as rabbits and pikas. They are opportunistic hunters and will also consume birds, bird eggs, amphibians, lizards, and insects, especially when other prey is scarce. Stoats can even take down animals significantly larger than themselves, such as adult rabbits.
Their hunting techniques are characterized by agility, speed, and stealth. They often move in a zig-zag pattern, systematically checking crevices for food, and can travel over 9 miles in a night to find prey. Prey is typically killed with a precise bite to the back of the neck, near the base of the skull, which severs the spinal cord. For larger prey like rabbits, the bite often causes shock rather than directly reaching the spinal column due to the stoat’s shorter canine teeth.
Their high metabolism necessitates frequent feeding, driving their active hunting behavior day and night. They are largely solitary animals, except during mating season or when a female is raising her young. Stoats do not dig their own burrows but instead utilize the dens and nest chambers of their prey, often lining them with fur from their kills. Their intelligence is evident in their hunting strategies, which can include a “weasel war dance” or erratic movements to confuse and mesmerize prey, making it easier to close in for the attack.