Japanese Squirrel (Sciurus lis)

OTHER NAMES: N/A

Latin Etymology: Sciurus ("squirrel") lis (?)

Adult Japanese Squirrel (Sciurus lis) at Kamakura, Japan - November 2014

Featured Subspecies: N/A
Length: 16-22cm  /  Weight: 250-310g
NO UK STATUS / IUCN Red List: Least Concern

The Japanese Squirrel is no way near as common as squirrels in the UK,being a creature of the mountain forests and even there not being present in the densities of the Grey Squirrel in the UK. Human encroachment has made them rarer in Japan and they are rarely seen around most urban areas, although Kamakura is apparently an exception. It is a slightly stockier looking animal than the British species, with more rounded ears and a more snub face.

Related Species:
Order: Rodentia
Family: Sciuridae
Genus: Sciurus
Subspecies: none - monotypic

 - Sighting Locations -

JAPAN - Japanese - ニホンリス  /  Nihonrisu  ("Japan Squirrel")

Japanese endemic species, compartively scarce

 - TOKYO/HOKKAIDO 2014 TRIP: Single individual seen in Kamakura 

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

Fox Squirrel (Sciurus niger)

OTHER NAMES: Eastern Fox Squirrel, Bryant's Fox-Squirrel
Latin Etymology: Sciurus ("squirrel") niger ("black")

Adult Fox Squirrel (Sciurus niger) at Berkeley, California - August 2022

Featured Subspecies: Unknown (introduced population)
Weight: 450-1130g  /  Length: 50-72cm
NO UK STATUS / IUCN Red List: Least Concern 

A distinctively orange squirrel which gives them their name, the Fox Squirrel is originally a species of the Eastern USA, but introductions have lead to it having populations in other places, such as California where I saw them. They favour oak, hickory, walnut, pecan and pine trees, but can be found in a wide range of forested habitats.

Related Species:
Order: Rodentia 
Family: Sciuridae 
Genus: Sciurus 
SUBSPECIES: S. n. niger, S. n. avicinnia, S n. bachmani, S. n. cubeeus, S. n. limitis, S. n. ludovicianus, S. n. rufiventer, S. n. shermani, S. n. subauratus, S. n. vulpinus

 - Sighting Locations -

UNITED STATES 
Range centred round the Mississipi Basin, with introduced populations elsewhere
 - CALIFORNIA 2022 TRIP: Seen at San Francisco and Berkeley

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Western Gray Squirrel (Sciurus griseus)

OTHER NAMES: Silver-Gray Squirrel, California Gray Squirrel, Oregon Gray Squirrel, Columbian Gray Squirrel, Banner-tail
Latin Etymology: Sciurus ("squirrel") griseus ("grey")

Adult Western Gray Squirrel (subspecies S. g. griseus) at Roy's Redwoods - August 2022

Featured Subspecies: Sciurus griseus griseus
Weight: 350-1000g  /  Length: 43-61cm
NO UK STATUS / IUCN Red List: Least Concern

The largrest arboreal squirrel of the Western United States, unlike it's counterpart the Eastern Grey, it does not have the substantial introduced ranged outside North America. Their fur is also entirely silver-grey and white, and doesn't have the rust coloured patches like the Eastern. They are more closely tie to forest than their more common counterparts.

Related Species:
Order: Rodentia 
Family: Sciuridae 
Genus: Sciurus 
SUBSPECIES: S. g. griseus, S. g. nigripes, S. g. anthonyi

 - Sighting Locations -

UNITED STATES 
Found in West Coast States

- CALIFORNIA 2022 TRIP: Seen at Roy's Redwoods

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Eurasian Red Squirrel (Sciurus vulgaris)

OTHER NAMES: Red Squirrel
Latin Etymology: Sciurus ("squirrel") vulgaris ("common") 

Adult Eurasian Red Squirrel (Sciurus vulgaris) at Vienna, Austria - October 2024

Featured Subspecies: ?
Weight: 10-15g  /  Length: 34-43cm
UK STATUS NOT EVALUATED/ IUCN Red List: Least Concern

The indiginous tree squirrel of Europe, the Red Squirrel is somewhat paradoxical in that overall it has an enormous range but within the UK specifically it is significantly struggling due to competition with the non-native grey squirrel which outcompetes it and carries pathogens which are fatal to reds. The result has led to a catastrophic population collapse and Reds are largely extipirated from England. While the population in the UK does have the namesame red fur, other populations are more variable into black, grey and brown such as the individual pictured above.

Related Species:
Order: Rodentia 
Family: Sciuridae 
Genus: Sciurus 
SUBSPECIES: S. v. alpinus, S. v. altacaicus, S. v. anadyrensis, S. v. arcticus, S. v. balcanicus, S. v. chiliensis, S. v. cinerea, S. v. dulkeiti, S. v. exalbidus, S. v. fedjushini, S. v. fusconigricans, S. v. leucourus, S. v. lilaeus, S. v. mantchuricus, S. v. martensi, S. v. ognevi, S. v. orientis, S. v. rupestris, S. v. ukrainicus, S. v. varius, S. v. vulgaris

 - Sighting Locations -

UNITED KINGDOM - A localised and declining resident
 - Seen in the Lake District

AUSTRIA - Austrian: esguilu - "Squirrel"

Common resident

 - VIENNA 2024: Seen in Vienna  

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Red-tailed Squirrel (Sciurus granatensis)

OTHER NAMES: N/A
Latin Etymology: Sciurus ("squirrel") granatensis (from Nueva Granada - an old name for Colombia)

Adult Red-tailed Squirrel (Sciurus granatensis)  at San Gerardo de Dota, Costa Rica - November 2025

Featured Subspecies: Sciurus granatensis hoffmanni
Weight: 212-520g  /  Length: 34-52cm
NO UK STATUS / IUCN Red List: Least Concern

A widespread species that can tolerate high altitudes well being found in not only the highlands of Costa Rica where I saw them, but also in the Northern Andes. It is another very variable species in appearance causing it to previously be mistaken for a large number of separate subspecies and species but current estimates have lowered it down to a more manageable level.
 
Related Species: 
Order: Rodentia 
Family: Sciuridae 
Genus: Sciurus 
SUBSPECIES: S. g. chapmani, S. g. chrysuros, S. g. granatensis, S. g. hoffmanni, S. g. morulus, S. g. nesaeus
 
- Sighting Locations - 

COSTA RICA 
A common resident
- COSTA RICA 2025 TRIP: Seen at San Gerardo de Dota

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Variegated Squirrel (Sciurus variegatoides)

OTHER NAMES: N/A
Latin Etymology: Sciurus ("squirrel") variegatoides ("variegated")

Adult Variegated Squirrel (Sciurus variegatoides) at Tarcoles, Costa Rica - November 2025

Featured Subspecies: Sciurus variegatoides rigidus
Weight: 500g  /  Length: 26cm
NO UK STATUS / IUCN Red List: Least Concern

A common and widespread squirrel species of Central America, as the name suggests they can have quite variable fur colouring with different quantites of orange, white, grey and black. It is an adaptable species, found in both forests, suburbs and plantations the latter of which it is often considered a pest. It is sometimes kept as a pet but has been inplicated in human deaths in Europe caused by disease transmission from captive animals. 

Related Species: 
Order: Rodentia
Family: Sciuridae
Genus: Sciurus
SUBSPECIES: S. v. goldmani, S. v. bangsi, S. v. managuensis, S. v. variegatoides, S. v. boothiae, S. v. belti, S. v. underwoodi, S. v. adolphei, S. v. dorsalis, S. v. atrirufus, S. v. rigidus, S. v. thomasi, S. v. loweryi, S. v. melania, S. v. helveolus
 
- Sighting Locations -

COSTA RICA 
A common and widespread resident
- COSTA RICA 2025 TRIP: Seen at Tarcoles and Alajuela

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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