YOU may think you know the animals that live in your immediate neighbourhood – but there are always surprises.

A few weeks ago, my husband was just in time to see a weasel dash from garden to garden across our quiet Ben Rhydding cul-de-sac.

When he was growing up in Cumbria he would have called it a stoat: there is considerable regional variation in this identification, leading to the famous “weaselly distinguished/stoatally different” joke.

However, this very small, sinuous, russet creature had no black tip to its tail so – according to the text books – it was a weasel, smallest of our British mustelids.

Mustelids are my favourite animal group: not only are they extremely beautiful and engaging – though often ferocious – characters but they also exemplify patterns of evolution.

Tiny weasels prey on small rodents, and can easily insinuate themselves into the smallest of burrows. Bad news for mice and voles.

A stoat, slightly bigger and immensely strong, also catches rabbits and even small hares, prey much larger and heavier than the little hunter.

Otters have taken to the water, rivers, lakes and inshore coastal regions; pine martens have evolved to pursue prey into the tree tops and can take birds, squirrels and also enjoy fruit, nuts and berries.

All of them are opportunists and will supplement their diet with carrion where available.

The most interesting mustelid to me is the largest, the badger.

Amazing to consider that this big ambling creature with its favourite food of earthworms and its ambling gait is a cousin of the quicksilver weasel that dashed across our road.

All other mustelids lead solitary lives except when mating or rearing young, yet badgers live socially in a sett built cooperatively.

Anyone watching badgers emerge on an early summer evening will be struck by their affectionate behaviour as they greet each other, mutually groom, play with the cubs and even all join in a glorious rough and tumble.

The zoologist Hans Kruk was puzzled by this bonding since, unlike say wild dogs or spotted hyenas, badgers do not hunt or even forage together.

After scrupulous research he concluded that the clan system enabled badgers to demarcate and defend a territory containing a variety of food sources, including cultivated fields where grazing animals kept the grass perfect for earthworms. So this, our largest British mustelid, evolved alongside us, learning to take advantage of our ancestors’ development from hunter-gatherers to pastoral farmers.