In this blog, find out about one of the UK’s most beloved mammals: OTTERS! From their troubled past to tracking them in the wild.
What are Otters?
The Eurasian Otter (Lutra Lutra) is a semi-aquatic mammal found in wetlands, rivers and sometimes along the coast in the UK. They are part of the Mustelid family which in Britain also includes Badgers, Weasels, Stoats, Polecats, Pine Martins and Mink. Their long slender body, muscular tail and webbed feet allow them to swim effortlessly through the water, while their sensitive whiskers allow them to efficiently capture their prey.
Otters are very widespread and are found on every continent besides Australia and Antarctica. The largest Otter in the world is the Giant Otter (nicknamed river wolf due to its sharp teeth and powerful body) which has the ability to predate on Caiman and Anaconda! They’re native to South America and inhabit rivers such as the Amazon, but can also be found in lakes, and marshes. The Asian Short Clawed Otter, as its name suggests, is the smallest species of Otter and is found throughout Asia. But in this blog, there’ll be no need to pack your suitcase as we’ll be focusing on the amazing European Otters that we have in the UK!
What do Otters eat?
Eurasian Otters are piscivores: approximately 80% of their diet consists of fish and eels. However, it’s not uncommon for them to eat amphibians, crustaceans, and even small birds like Moorhens! Unfortunately, eels are now in steep decline. Due to eels making up a significant proportion of an Otter’s diet, there are concerns about the impact this may have on Otters. The diet of an Otter sometimes varies seasonally, as they take advantage of new opportunities throughout the year. For example, during Spring, spawning frogs and toads are seen as a tasty snack. While in Summer, ducklings can be snatched as an easy meal by an Otter lurking underneath the water.
The Otter comeback!
Otters have made an astonishing comeback from the brink of extinction in the UK! Otters were absent from most of the country just 60 years ago but are now present in all counties within England! But what caused their devastating decline in the mid to late 1900s? Due to their already elusive nature, proving the disappearance of Otters from our waterways was difficult. Following the first national Otter survey in 1977, it was discovered that within 90% of the sites where Otters had been present, they were now absent. Initially, the blame was directed at the straightening of rivers, overfishing, and urbanisation. Although these factors certainly had negative effects, it was evident that something much worse was causing these localised extinctions.
During the 1940s, Dichlorodiphenyltrichloroethane (we’ll stick with DTT for short) gained popularity in farming as a pesticide. As well as targeting pests, it was quickly absorbed by the soil and washed into our rivers. The delicate river ecosystems were ruined and our rivers began to die.
Eels have a very high-fat content, so they, therefore, store large amounts of toxins within their flesh. As previously explained in this blog, Eels make up a significant proportion of an Otter's diet as the Otters continued to consume contaminated Eels, pesticides built up in their reproductive organs. Their immune system was also weakened making them vulnerable to diseases. Following the ban of DTT in 1986, alternative pesticides began to be used, however, they were discovered to be just as damaging.
Luckily, our rivers and lakes today are healthier than they’ve been for decades. Wildlife is returning - including our Otters! The recovery of the Otter is one of the best conservation success stories of the 21st century as they can now be found in every British county. Although the future is looking bright for our Otters, they’re continuing to face challenges.
Otter spotting:
Despite the European Otter making a massive comeback within the UK, these elusive mustelids are still challenging to spot in the wild. However, don’t be put off by their illusiveness. The adventure of tracking down these mysterious animals is all part of the fun. The thrill and excitement of catching a glimpse of an Otter will make the long wait worth it!
To make sure you’re looking in the right places, it’s helpful to find evidence that Otters are actually in the area. For example, an Otter pawprint has five toes, compared to a dog pawprint which has only four toes. Check areas with mud or damp sand. You might even see the ‘drag’ of its tail. Another indication of the presence of Otters is spraints. They are often said to smell of jasmine tea and it will likely consist of fish bones, scales, feathers, and shells. Once you’ve found a possible Otter habitat, leaving a camera trap/trail camera nearby can be useful to confirm your suspicions and if you’re patient, you may well be lucky enough to capture some Otter footage!
Dawn and dusk are the best times to go out looking for Otters. Make sure to tread quietly and avoid chatting. Keep a low profile and walk into the wind to prevent any Otters from scenting you.
It is illegal to disturb Otters so make sure to admire them from a distance.
Thank you for reading! I hope you learned something about, in my opinion, our best mammal in the UK. Make sure to follow our social media sites listed below :)
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Photos: Reece Smith