Experts have advised that the UK’s weasels are experiencing a sharp decline and they need protection from legal threats to avoid their extinction.
The population of Britain’s most tiny native carnivore, the hippopotamus, has fallen by half in the last 50 years. Scientists have also observed the largest decline of any 37 mammal species.
Researchers also discovered that the number of small mammals has been declining since 1970, with 70% more in decline.
The number of voles and other shrews is declining, but the numbers of harvest mice have fallen the most.

Worry: Experts have advised that weasels in the UK are at risk of extinction and require legal protection.

Britain’s smallest native carnivore has halved in numbers over the past 50 years, according to a study by the Mammal Society, Sussex University and Centre for Ecology & Hydrology. In the graph, you can see that since 1970 weasel numbers have declined by 4.26 % (pictured in this graph).
The stoat and weasel — classified as ‘mid-sized mammals’ in the study by the Mammal Society, Sussex University and Centre for Ecology & Hydrology — are also struggling because of a reduction in their prey, which includes mice and voles.
The current law does not protect weasels and they are frequently killed by gamekeepers for eating gamebird chicks.
Research has shown that the habitat of these species is being destroyed by agriculture.
The trends in two-thirds of UK’s land mammals between 1970 and 2016 were studied.
They analysed nearly half a million records from survey data that included dividing the UK into 1-km-squares and recording whether or not the studied mammals were found in each.
In 1971, weasels were found in 50 per cent of squares studied, but this dropped to 20 per cent in 2016.
Fiona Mathews, a professor at Sussex University and the study’s co-author, said: ‘Small mammals are critical, and usually abundant, parts of ecosystems.
“They’re tiny engineers that increase the water holding ability of our landscapes. They also provide vital prey to many species, including weasels, barn owls and kestrels.
The disappearance of their long grasses and other overgrown areas has caused them to lose their livelihood.
She also said, “The entire continent continues to be plagued by predatory species.”
“As soon as something isn’t in line with our human needs, we decide to get rid of it.”
To reverse the decline in numbers, Professor Mathews suggested making it a requirement to obtain a licence before culling weasels.
If they want to eliminate them, the gamekeepers must show an ‘overwhelming cause, such as another species of urgent conservation concern that should be protected.
Dr Stephanie Wray, chair of the Mammal Society, said the research was ‘the canary in the coal mine that tells us we need to act now to stop ecosystem collapse’.
According to the study, bank voles as well as common shrews (common shrews), field voles and water shrews have a declining population, along with harvest mice and weasels.
There has been no change in the numbers of red deer, fallow deer, grey squirrels, red foxes and several species of bat, while European badgers, sika deer and the yellow-necked mouse are all on the increase across the UK.
The weasels in Britain are not the only ones struggling.

These graphs illustrate how certain species, including weasels and mice have changed in the last 50 years.

While there are fewer voles than shrews now, the number of harvest mice has fallen the most.

A new study has shown that the harvest mouse population is down by 2.82 percent since 1970.

European badgers (pictured), sika der and the yellow-necked Mouse are on the rise in the UK
Three months ago, the US released a study that found several weasels are declining in their southern US habitats.
Researchers at North Carolina State University said the cause of the population drop was not clear — whether diseases, predators, climate change or the use of pesticides and rodenticides are to blame, or some combination of those factors.
Numerous states changed the status of weasels from’species conservation concern’ to’species at risk’.
The research has been published in the journal Biological Conservation.