Out of sight, out of mind – the UK is full of small mammal carnivores that you might well not have heard of…

When asked to think about what a mammal carnivore looks like you may at first picture large predators of faraway continents, from lions to hyenas. But a whole array of small carnivores can be found here in our grasslands, forests and waterways. These are animals known as mustelids, and here at Chester Zoo, we’ve been monitoring them for some time.

Take a look at the species and unique videos we’ve captured.


At just 15-26cm in length, weasels are among the very smallest species of the Order Carnivora, which contains the majority of the world’s “meat-eating” land mammals. The species is relatively common as mustelids go, and their distinctive red-brown coat and white chests/underbellies make them an easily recognisable sight. But few people in Britain are likely to have ever seen one – why?

It comes down to habitat choice. Weasels’ preferred hunting grounds are woodlands, grasslands and farmlands where there’s plenty of small mammal prey to be found, and generally the species will avoid urban areas. While the species remains common for now, continued urbanisation and shifts in small mammal populations due to intensifying agricultural practices means we need to keep a watchful eye on weasel numbers.

Here on the Chester Zoo estate weasels are among the most commonly spotted predators in camera trapping, and appear frequently in our “mostela” camera trap boxes that aim to entice passing mustelids. Their presence here is an encouraging sign that the habitat we’re managing as well as our nature-friendly farming practices are making a difference.


Stoats are similar to weasels on the surface – a brown colouration combined with a white underside – but the species have two key physical differences. The stoat is slightly larger in size, with males achieving a length of up to 40cm, and carries a distinctive black tip on its much longer and bushier tail.

The stoat’s choices of prey overlap with the weasel’s: voles, mice, small birds, and even species that outsize the predator such as rabbits and hares. They also share a common distribution across the UK and strong population numbers for the time being, despite centuries of persecution, and so stoats are seen in our mostelas and across our local ecosystem.


Significantly less universally found across the UK is the polecat. In fact, the polecat is one of the most elusive and hard to spot species in the country, with few direct sightings even among specialist conservationists. The polecat saw fierce persecution in centuries prior to the point that it was exterminated in many places, particularly in the north. Over the decades since though its recovery has been a successful one, and the polecat can be sighted by camera traps across England and Wales.

Despite its rarity, you may find a picture of one seems very familiar. Polecats are the wild ancestor of the domestic ferret, and share much in common in terms of size and shape. You can normally distinguish a true wild polecat however by the unique white marks of its face that stick out against the browns of its fur – browns that are generally darker in complexion than most ferrets.

Polecats’ elusive behaviour sees them often spending time in particularly dense areas of woodland, and individuals will generally roam huge distances in search of prey – many kilometres per night’s hunting. It’s for these reasons that the best footage of polecats on the Chester Zoo estate comes in the very darkest hours.


Now, it is the biggest UK mustelids that remain on our list.


The black-and-white striped face of the badger is one of the most known wildlife images in Britain. Our largest surviving native carnivore and one of our largest land mammals overall, the badger has captured the hearts of the nation and appears throughout our media and stories. Though few are lucky enough to see a wild badger with their own eyes.

The protected woodland and open grasslands here on the zoo site offer the perfect habitat for multiple badger family groups to survive. As badgers occupy known setts for extended periods of months or years, they’re much easier to monitor than the other mustelids known to frequent our site. The footage we’ve captured has provided a wealth of information, from the relationships of badgers within and between setts, through to the raising of cubs.


The nation’s only aquatic mustelid, the otter is adapted for a life centred around water. European otters approach nearly a metre in size, putting them on par with badgers, thought the two couldn’t be much more different. While the badger enjoys an omnivorous diet of soil invertebrates and plants, otters are fish specialists, able to hunt in both fresh and saltwater.

This year brings big news, the first ever camera trap recording of an otter on Chester Zoo land. Even better, this particular camera is stationed on the pond area of the free to access Chester Zoo Nature Reserve. Our team have been working hard to ensure our pond habitats are thriving and full of life, and so the presence of an otter foraging here is a great sign.

A future… 

Five out of six UK native mustelids on one Chester Zoo site. That’s an extraordinary achievement and one we’re very proud of. Habitat management and improvement will only continue, alongside wildlife monitoring, and so in time we’ll only understand more about these unique British carnivores.

One species remains unseen here – the pine marten – a species once exterminated completely from England and Wales, and now slowly returning. Towards the end of the 2010’s we helped support translocations of wild pine martens from Scotland to Wales with the Vincent Wildlife Trust, and it’s hoped in time their population will grow and their range will expand until they too appear on our camera traps at Chester Zoo.

Until then, stay tuned.

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