Stoat

Ermine

In northern and upland Britain, stoats moult to a white winter coat — the famed ermine of heraldry and royal robes. The white coat provides camouflage against snow, but the black tail-tip is retained throughout, thought to serve as a decoy — a predator strikes at the conspicuous tail-tip rather than the body. In southern Britain, stoats tend to remain brown year-round or turn only partly white.

Hunting rabbits

Stoats are specialist hunters that routinely kill rabbits many times their own weight. They use a combination of speed, persistence, and what appears to be a hypnotic “war dance” — leaping, twisting, and tumbling near a rabbit group until the rabbits freeze in apparent paralysis, allowing the stoat to close in for the kill. This behaviour, called “stotting,” may simply be play that happens to disorient prey, or it may be a genuine evolved hunting strategy.

Reproduction

Stoats have one of the strangest reproductive strategies of any British mammal. Mating occurs in summer, but implantation of the fertilised egg is delayed for up to ten months — the embryo remains dormant until the following spring. This means a litter of four to six kits is born in the spring when prey is abundant, regardless of when mating occurred. Female stoats can be mated as kittens, still in the nest, before their eyes have opened.

Predator of ground-nesting birds

On moorland and in upland areas, stoats are significant predators of ground-nesting birds including curlew, lapwing, and red grouse. Their elongated body shape allows them to enter burrows and nest holes. In Britain, stoat predation is one of the pressures on upland bird populations, and stoat control is practised on some managed grouse moors and conservation reserves.