Squirrel Species: A Fascinating Look at Nature’s Tree-Dwellers

Introduction

Whether scampering through ancient woodlands or darting across city gardens, squirrels are endlessly fascinating—and far more diverse than many realise. In the UK, the adorable Eurasian red squirrel and the widespread eastern grey squirrel capture our attention.

Beyond their charm, these creatures are vital to biodiversity, dispersing seeds, shaping forest renewal through selective foraging, and serving as prey for hawks, owls, and foxes in South Yorkshire’s woodlands.

These curious members of the Sciuridae family, which includes tree squirrels, ground squirrels, and flying squirrels, play a critical role in ecosystems, spreading seeds and shaping forests.

This article explores squirrel species globally, with a focus on the UK’s red squirrel and invasive eastern grey squirrel, while introducing other remarkable species like the fox squirrel, Douglas squirrel, and Malabar giant squirrel to highlight their diversity.

Types of Squirrels

The Sciuridae family is diverse, encompassing:

• Tree Squirrels: Agile climbers like the UK’s Eurasian red squirrel and eastern grey squirrel, alongside North America’s fox squirrel, western grey squirrel, American red squirrel, Abert’s squirrel, and Asia’s vibrant Prevost’s squirrel and Malabar giant squirrel.

• Ground Squirrels: Burrow-dwellers like the Richardson’s ground squirrel, Arctic ground squirrel, rock squirrel, antelope squirrel, African ground squirrel, California ground squirrel, and Indian palm squirrel, adapted to open landscapes.

• Flying Squirrels: Nocturnal gliders, such as the southern flying squirrel, northern flying squirrel, Siberian flying squirrel, and Japanese dwarf flying squirrel, with skin membranes for gliding.

Notable Species Around the World

Beyond the UK, squirrel diversity captivates:

• Fox Squirrel: North America’s largest tree squirrel, with a rusty coat, thrives in mixed forests.

• Douglas Squirrel: A Pacific Northwest pine squirrel, known for its chatter and cone-hoarding.

• Prevost’s Squirrel: A striking Asian species with black, white, and red fur, often in rainforests.

• Malabar Giant Squirrel: India’s multicoloured giant, leaping through tropical canopies.

• Pallas’s Squirrel: Found in Southeast Asia, with a sleek, reddish coat.

• Black Giant Squirrel: A massive Southeast Asian species, dwelling in dense forests.

• Japanese Squirrel: A small, reddish tree squirrel native to Japan’s woodlands.

• African Pygmy Squirrel: The world’s smallest, barely 10cm, scurrying in African rainforests.

• Arizona Gray Squirrel: A southwestern US species, adapted to arid oak woodlands.

• Black Squirrel: A melanistic variant of the eastern grey squirrel, common in urban areas.

These animals aren’t just cute—they’re ecological engineers. From burying nuts that grow into new trees, to acting as prey in delicate food webs, squirrels are essential to their ecosystems.

Geographic Distribution

Squirrels inhabit every continent except Antarctica and Australia:

• UK Focus: The native Eurasian red squirrel thrives in Scotland, Northern England, and isolated areas like the Isle of Wight. The eastern grey squirrel, introduced from North America, dominates England, Wales, and parts of Scotland, particularly in the east of the UK.

• North America: Home to fox squirrels, western grey squirrels, American red squirrels, Abert’s squirrels, southern flying squirrels, northern flying squirrels, Richardson’s ground squirrels, Arctic ground squirrels, rock squirrels, antelope squirrels, and California ground squirrels.

• Europe: Eurasian red squirrels are widespread, but eastern grey squirrels are invasive in the UK and Italy.

• Asia: Hosts Prevost’s squirrels, Malabar giant squirrels, Pallas’s squirrels, Japanese squirrels, black giant squirrels, Indian palm squirrels, and Siberian flying squirrels.

• Africa: Includes African ground squirrels and African pygmy squirrels.

• South America: Features red-tailed squirrels and Neotropical pygmy squirrels.

British Red Squirrel Conservation and Grey Squirrel Control

Physical Characteristics

Squirrels vary widely in appearance:

• UK Eurasian Red Squirrel: 18–24cm body, reddish-brown fur (orange to russet), tufted ears (prominent in winter), bushy tail.

• UK Eastern Gray Squirrel: 24–28cm body, grey fur (sometimes brownish or black squirrel variant), no ear tufts, bushy tail.

• Size: From the 10cm African pygmy squirrel to the 70cm Malabar giant squirrel or black giant squirrel.

• Colour: Fox squirrels show rusty hues, Prevost’s squirrels boast tricolour patterns, and Pallas’s squirrels have reddish coats.

• Tail Structure: Bushy tails, like those of Douglas squirrels or Japanese squirrels, aid balance and communication.

• Markings: Abert’s squirrels have distinctive ear tufts; antelope squirrels sport white stripes.

Squirrels as Rodents

Squirrels are proud members of the Rodentia order, the largest group of mammals, defined by their ever-growing incisors. Both Eurasian red squirrels and eastern grey squirrels in South Yorkshire’s woodlands have a single pair of upper and lower incisors that grow up to 15cm per year in larger species like the fox squirrel.

To keep these teeth manageable, squirrels gnaw on bark, nuts, and even garden fences, a habit familiar to UK homeowners. This constant chewing, seen in tree squirrels like the Douglas squirrel or ground squirrels like the California ground squirrel, maintains their dental health.

What sets Sciuridae apart from other rodents, like mice or beavers, are their specialised limbs and sharp vision, perfect for climbing, gliding in flying squirrels like the Siberian flying squirrel, or caching seeds.

These adaptations make squirrels agile forest dwellers, vital to ecosystems from Sheffield’s parks to global woodlands.

The UK’s Red and Grey Squirrels: A Closer Look

Red Squirrel (Sciurus vulgaris)

Once common across the UK, the red squirrel has declined significantly due to habitat loss, disease, and competition from the introduced grey squirrel. Conservation efforts are active in parts of Scotland, Cumbria, Northumberland, and isolated areas of Yorkshire.

Eastern Grey Squirrel (Sciurus carolinensis)

Brought to the UK in the late 19th century, grey squirrels have outcompeted reds in most regions and are now classified as an invasive non-native species under UK law.

Important Legal Note:

• Under the Wildlife and Countryside Act 1981 and Invasive Alien Species (Enforcement and Permitting) Order 2019, it is illegal to release a grey squirrel once caught.

• All controls must be humane and carried out by qualified professionals who understand their legal obligations.

• Always consult a BPCA-certified pest controller for compliant management.

Pest Control, Legal Compliance, and Wildlife Ethics

While squirrels can become pests—especially grey squirrels nesting in lofts or chewing on wiring—any control action in the UK must be legally compliant and humane.

Key Legal Considerations for Grey Squirrel Control:

• You must not release a captured grey squirrel into the wild

• You must use humane dispatch methods, in line with DEFRA and BPCA guidance

• Only trained professionals should handle squirrel control

• Use of poisons for squirrels is illegal in the UK

• Pest controllers must follow HSE-approved products and methods

• Red squirrels are legally protected and must not be disturbed under any circumstances

For safe, effective, and ethical squirrel removal, choose technicians certified by:

• BPCA (British Pest Control Association)

• RSPH (Royal Society for Public Health)

Behavioural Traits

Squirrels are endlessly intriguing, with complex behaviours that shape their survival:

• Arboreal Movement: Eurasian red squirrels are nimble in coniferous forests; eastern grey squirrels excel in urban and deciduous settings. Malabar giant squirrels leap vast distances in canopies.

• Decoding Communication and Social Life:

  • Nonverbal Cues: Tail flicking is a universal signal among tree squirrels like the eastern grey squirrel and fox squirrel. Rapid flicks warn of predators (e.g., hawks in South Yorkshire) or deter intruders, confusing their exact position. Postures, like crouching or piloerection (hair standing on end), signal readiness to chase or defend, especially in urban parks where greys compete.

  • Vocalisations: Eurasian red squirrels and American red squirrels produce barks, screeches, and “kuk-kuk” sounds. Short barks alert others to aerial threats, prompting defensive huddling. Studies on American red squirrels show unique “rattle” calls that identify individuals, reinforcing territorial boundaries. Flying squirrels, like the Siberian flying squirrel, use ultrasonic chirps for navigation or nest communication, inaudible to humans.

  • Scent-Marking: Both California ground squirrels and UK squirrels use cheek and flank glands to leave olfactory markers on trees or rocks. These “invisible signatures” act as territorial boundaries or mating signals, with males like eastern grey squirrels intensifying marks during breeding season to attract females.

  • Social Structures: Most tree squirrels, including Eurasian red squirrels and fox squirrels, are solitary, sharing nests only in harsh winters. Conversely, ground squirrels like California ground squirrels or prairie dogs (close relatives) form colonies with cooperative alarm systems and shared burrows, enhancing survival in open habitats.

  • Territoriality: In high-density areas like Sheffield’s parks, eastern grey squirrels defend core territories (~0.2 hectares) with chases and chattering. Eurasian red squirrels fiercely protect forest patches, especially females raising young. Juveniles disperse to establish new territories, with males showing heightened aggression during mating season.

•  Social Dynamics: Richardson’s ground squirrels form colonies; Japanese squirrels and Eurasian red squirrels are solitary.

Diet and Foraging Habits

Squirrels are resourceful foragers:

• What They Eat: Eurasian red squirrels prefer pine seeds; eastern gray squirrels eat acorns, fruits, and scraps. Fox squirrels and Abert’s squirrels target nuts; African ground squirrels include roots.

• Foraging Strategies: Scatter-hoarding by Douglas squirrels and American red squirrels ensures winter survival. Indian palm squirrels adapt to urban food sources.

• Seasonal Changes: Arctic ground squirrels hibernate, relying on stored food; eastern grey squirrels forage year-round.

Habitat and Range

Squirrels adapt to diverse environments:

• UK Eurasian Red Squirrel: Prefers coniferous forests, struggling in urban areas.

• UK Eastern Gray Squirrel: Thrives in cities, parks, and deciduous woodlands, exploiting human-altered landscapes like Sheffield’s Endcliffe Park or Doncaster’s gardens in the east of the UK. Their agility, high reproductive rate, and omnivorous diet make urban areas ideal, with city parks mimicking woodlands through mature trees and steady food sources. Gardens offer nesting sites, while rooftops and chimneys replace tree hollows.

• Squirrels in Urban Environments:

  • Urban Adaptation: In South Yorkshire and the east of the UK, eastern grey squirrels dominate urban spaces, from Rotherham’s Clifton Park to Barnsley’s backyards. Their ability to exploit human food sources (e.g., bird feeders, scraps) and nesting opportunities (e.g., attics) expands their habitat. Fewer predators, like hawks or foxes, in cities enhance their survival.

  • Feeding Impacts: Human feeding, common in UK parks, alters squirrel behaviour. A 2018 study found urban eastern grey squirrels spend 42% less time foraging when fed peanuts or bread, becoming bold enough to approach within 1.5 metres of humans. This habituation can lead to aggressive food-seeking, frustrating homeowners.

  • Managing Conflict: To coexist, non-lethal methods work best. Sealing entry points with metal mesh, using motion-activated sprinklers, or removing food attractants like open bins prevents issues. In some regions, fertility control trials stabilise populations without harm.

  • Integrated Pest Management for Squirrels: Integrated Pest Management (IPM) offers a sustainable approach to controlling eastern grey squirrels. Assessing properties for entry points (e.g., attics, chimneys) and using exclusion techniques like metal mesh prevents nesting. Habitat modification, such as trimming tree branches near buildings, reduces access. Squirrel-proof feeders protect bird food, while clearing fallen fruit minimises attractants. Gnawing on wood and wiring can damage homes, so resource management is key. Apex Pest Control applies IPM in South Yorkshire and the east of the UK, ensuring humane, effective solutions that balance biodiversity with property protection.

• Global Habitats: Malabar giant squirrels and black giant squirrels inhabit tropical forests; Arizona grey squirrels prefer arid woodlands; California ground squirrels burrow in grasslands.

Reproduction and Lifecycle

Squirrels’ life cycles are dynamic:

• Mating: Eurasian red squirrels and eastern grey squirrels breed twice yearly.

• Gestation: 38–39 days for reds, 44–46 days for greys.

• Offspring Development: Kits, like those of southern flying squirrels or Japanese squirrels, mature in 6–10 weeks.

Conservation Status

Squirrel populations face varied challenges, with conservation efforts critical to maintaining biodiversity:

• UK Eurasian Red Squirrel: Endangered, with only ~120,000 left, primarily in Scotland, Cumbria, and isolated areas like the Isle of Wight. Competition from the invasive eastern grey squirrel and squirrelpox, a virus deadly to reds, threatens their survival. South Yorkshire initiatives, like nest box programs in the Peak District and humane grey squirrel control, support red squirrel recovery. Community efforts, such as volunteer monitoring in Sheffield, bolster habitat protection and raise awareness.

• UK Eastern Gray Squirrel: Invasive, with ~2.5 million across the UK, outcompeting reds and damaging trees by stripping bark. Control measures, including targeted culling in conservation zones like Cumbria, aim to protect red squirrels and woodlands. In urban areas like Doncaster, greys are managed to prevent property damage, balancing their adaptability with ecosystem health.

• Global Context: The African pygmy squirrel faces habitat loss from deforestation in rainforests, while the Malabar giant squirrel is threatened by logging in India’s Western Ghats. Siberian flying squirrels decline due to forest fragmentation in Asia. Conversely, American red squirrels and Douglas squirrels remain stable in North American forests, and fox squirrels thrive in mixed woodlands despite urban sprawl. California ground squirrels are agricultural pests, prompting control measures in the US.

• Biodiversity Impact: Squirrels like Pallas’s squirrels, Prevost’s squirrels, and Eurasian red squirrels aid forest regeneration through seed dispersal, vital for healthy ecosystems. However, invasives like eastern gray squirrels disrupt native flora and fauna, competing with birds and other mammals. Conservation strategies, including rewilding and predator management (e.g., pine martens in Scotland to control greys), help restore balance. Global efforts focus on protecting habitats for species like the black giant squirrel and Japanese squirrel, ensuring their ecological contributions endure.

• Local and Global Solutions: In South Yorkshire, organisations collaborate to monitor red squirrel populations and manage grey squirrel impacts. Globally, protecting tropical forests for Malabar giant squirrels and temperate zones for Siberian flying squirrels addresses climate change and habitat loss, preserving squirrels’ role as nature’s gardeners.

Ecological Role of Squirrels

Squirrels are nature’s unseen engineers, shaping ecosystems in vital ways:

• Seed Dispersal and Forest Regeneration: Eurasian red squirrels and eastern grey squirrels scatter-hoard seeds, burying acorns and pine seeds across woodlands like those in South Yorkshire’s Peak District. Studies show grey squirrels bury thousands of acorns yearly, with 20–40% left unrecovered, germinating into new trees. Douglas squirrels, or pine squirrels, play a similar role in North American forests, ensuring tree regeneration and resilience.

• Predator-Prey Dynamics: Squirrels are key prey for hawks, foxes, and owls in the UK and beyond. In woodlands, eastern grey squirrels make up a significant portion of raptor diets, supporting predators in fragmented urban habitats like Sheffield’s parks.

• Fungi Dispersal: Pine squirrels like the Douglas squirrel eat truffle-like fungi, spreading spores through their droppings. This fosters mycorrhizal networks, helping trees in nutrient-poor soils absorb phosphorus and nitrogen, crucial for forest health.

• Additional Impacts: Digging by California ground squirrels aerates soil, aiding root growth. Abandoned nests of Eurasian red squirrels provide shelter for insects and small mammals. By recycling organic material, squirrels enhance forest ecology, making them indispensable to woodland ecosystems.

Experts and Resources on Squirrel Species

The fascinating world of squirrel species is illuminated by dedicated organisations and researchers, offering insights that enrich our understanding of these tree-dwellers. In the UK, the Red Squirrel Survival Trust (RSST) leads efforts to protect the Eurasian red squirrel, providing resources on their behaviour and conservation challenges, such as squirrelpox and competition with eastern grey squirrels.

Their work in Cumbria and Scotland, including nest box programs, inspires South Yorkshire communities to support local biodiversity. The Yorkshire Wildlife Trust, active in Sheffield and Doncaster, educates homeowners on red squirrel habitats, encouraging eco-friendly gardening to coexist with wildlife.

Globally, the University of Guelph has advanced squirrel communication studies, notably their 2005 bioacoustic analysis of American red squirrel “rattle” calls, revealing how vocalisations define territories.

Similarly, UC Davis research on California ground squirrels highlights their cooperative alarm systems, informing conservation strategies for social species. The Smithsonian Institution explores unique behaviours, like red squirrel disease transmission, adding depth to global Sciuridae knowledge.

Educational platforms like National Geographic captivate readers with vivid profiles of fox squirrels, Malabar giant squirrels, and Siberian flying squirrels, while BBC Wildlife offers UK-focused content on red and grey squirrel dynamics, perfect for South Yorkshire nature-lovers.

These entities provide accessible resources, from RSST’s conservation guides to National Geographic’s visual storytelling, helping homeowners understand urban squirrel behaviour.

By learning from these experts, we appreciate squirrels’ ecological roles and the need for balanced management. Explore more about these fascinating creatures in our guide to grey squirrel removal to see how Apex Pest Control applies this knowledge locally.

Where to find red squirrels?

Maps displaying grey squirrel spread and red squirrel decline between 1945, 2000 & 2010. By Dr Craig Shuttleworth, scientific adviser to the Red Squirrel Survival Trust.

Image credit: Red Squirrel Survival – www.rsst.org.uk/where-to-find-red-squirrels/

Red and Grey Squirrel Sightings recorded in Scotland.

Image Credit: www.scottishsquirrels.org.uk 

Frequently Asked Questions About Squirrels

What is the difference between red and grey squirrels in the UK?

Eurasian red squirrels are smaller (18–24cm), with reddish fur and tufted ears, preferring coniferous forests. Eastern grey squirrels are larger (24–28cm), with grey (sometimes black) fur, no ear tufts, and thrive in urban areas like Sheffield. Reds are native but endangered; greys are invasive, carrying squirrelpox.

Can squirrels live together, or are they solitary?

Most tree squirrels, like Eurasian red squirrels and fox squirrels, are solitary, sharing nests only in harsh winters or breeding. Ground squirrels, like Richardson’s ground squirrels, form social colonies with shared burrows, using cooperative alarms to boost survival.

Why do squirrels chase each other?

Chasing reflects territorial defence or mating behaviour. Eastern grey squirrels in South Yorkshire parks protect ~0.2-hectare territories with chases. Males chase females during mating season, while juveniles play-chase to establish dominance, a common sight in urban gardens.

How do squirrels survive winter?

Eurasian red squirrels and eastern grey squirrels rely on scatter-hoarded nuts stored in autumn. Arctic ground squirrels hibernate in burrows, while flying squirrels like the Siberian flying squirrel share nests for warmth, ensuring survival through UK winters.

Are squirrels harmful to gardens or homes?

Eastern grey squirrels can dig up bulbs, raid bird feeders, or nest in attics, gnawing on wood and wiring. Humane solutions like exclusion techniques or squirrel-proof feeders manage issues. Apex Pest Control offers eco-friendly help in South Yorkshire to protect your home.

Conclusion

From the adorable Eurasian red squirrel to the adaptable eastern grey squirrel, and exotic species like the Malabar giant squirrel or Japanese dwarf flying squirrel, these creatures are nature’s architects. Understanding their diversity enriches our appreciation of wildlife. Curious to learn more about squirrel behaviour in your area? Explore our guide to grey squirrel removal for Apex Pest Control’s expert solutions.