The weasel is small. Really small. Much smaller than most people realise. It is not only the smallest mustelid, it’s also the smallest carnivore in the world. Growing to between 13 and 26 cm in length and weighing as little as 25 grams in some cases – about the same as an AA battery – it is a mere 0.0025% of the weight of the planet’s biggest terrestrial carnivore, the polar bear.