In this month’s North East Nature Journal, Christopher Wren, NHSN Naturalist, shares insights into the smelly world of mustelids.
It’s a Smelly Old World
We humans have a poorly developed sense of smell so it is difficult for us to appreciate how important it is for most other mammals. Mustelids, in particular, use scent to communicate with others of their kind, marking their territories and advertising their presence and breeding condition. With the exception of badgers, female and male mustelids lead separate lives, usually meeting only for courtship and mating. As they have large territories, are thinly spread across the landscape and are mainly active at night, scent-marking is a vital way for them to tell who is about and who is available.
Otter cubs are already leaving their own scent marks and sniffing others’ by the time they first appear on the cameras at three or four months of age. The first video, from late 2024, shows two young otter cubs exploring their world, much more interested in the scents than the sights or sounds.
Otters use spraint (otter poo), urine and anal jelly to leave scent marks, choosing prominent features such as rocks and grass tussocks. This video shows a popular sprainting spot which is very regularly visited by the dog otter and (separately) by the mother and cubs – there is fresh spraint every time I look. It was interesting to see it marked by a badger as well on this occasion – a behaviour known as “musking”.
Badgers’ family dynamics are rather different from otters’ but they use latrines to mark their territories and they scent-mark each other to reinforce the clan smell and maintain family bonds. Here’s an example with a mother repeatedly making sure her cub smells like the rest of the family, using sub caudal glands under her tail – a process called “allomarking”.
Polecats are notoriously smelly to our sensibilities (another name is foulmart) but it obviously works for them. The next video shows a polecat using urine, scat and body rubbing to advertise its presence and sniffing to see who else has been around.
The smaller mustelids are the more elusive they become. Tracking weasels and stoats is very difficult so less is known about their territorial behaviour. Field signs are usually very few but this weasel left a message inside my camera box. It was also scent marking by rubbing its body along the entrance pipe as it went in and out, something that happens nearly every time.
You can get more updates on local wildlife from Christopher Wren on his own TrogTrogBlog. You can discover the wildlife of Gosforth Nature Reserve here.