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Unstriped ground squirrel
Unstriped ground squirrel
Unstriped ground squirrel
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Unstriped ground squirrel
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Sciuridae
Tribe: Xerini
Genus: Xerus
Hemprich & Ehrenberg, 1833
Species:
X. rutilus
Binomial name
Xerus rutilus
(Cretzschmar, 1828)

The unstriped ground squirrel (Xerus rutilus) is a species of rodent (order Rodentia) in the family Sciuridae. It is the only member of the genus Xerus. It is found in Djibouti, Eritrea, Ethiopia, Kenya, Somalia, Sudan, Tanzania, and Uganda. Its natural habitats are dry savanna and subtropical or tropical dry shrubland.

Description

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The unstriped ground squirrel is brownish or tawny in color with a lighter colored front. As the name suggests the X. rutilus differs from other species of African ground squirrel by not having dorsal-running longitudinal white stripes. The eye is ringed with white hair (all hair being coarse in observed specimens). Their small head and body measure on average 225.8 millimetres (8.89 in) long with an average tail length of 172 mm (6.8 in). This tail is flat in appearance. Body weight varies across studies and habitats and ranges from 257.7 to 420 grams (9.09 to 14.82 oz).[2][3] The length of the hind foot is 35–49 mm with a braincase measuring only 24–25 mm. The length of the mandible is variable in the range of 31.0 to 33.9 mm.[3][4]

Xerus rutilus is a member of the Xerini tribe, but differs from its sister group Xerus daamsi. Both are separate and distinct from the North African equivalent Atlantoxerus.[5] Vibrissae (whiskers) length and brain size are both smaller than arboreal squirrels of the region, but are similar to other terrestrial squirrels.[3]

No significant sexual dimorphism is noted in X. rutilus.

Local and indigenous names

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In Tigrinya language: ምጹጽላይ or ጨጨራ (mitsutsilay, chechera).[6]

In Turkana: [ekuɲuk], borrowed further in Daasanach: [ɲékuɲug][7]

Ecology

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Range and habitat

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The unstriped ground squirrel is endemic to Ethiopia,[6] Kenya, Sudan, Tanzania, Djibouti, Eritrea and Uganda and probably extant in Somalia.[8] Its natural habitats include dry (arid) savanna and subtropical or tropical dry shrubland. Populations occupy many overlapping regions with its sister group, the striped ground squirrel (X. erythropus), in northeastern Africa.[9] X. rutilus dig and occupy burrows in generally arid conditions.[3]

Diet and foraging

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The unstriped ground squirrels demonstrate diurnality with an omnivorous diet consisting of leaves, tree fruits (Adansonia digital), seeds (Commiphora and Acacia trees), other plant materials, and insects.[3] Studies show that X. rutilus is unaffected by poisonous tannins and to some degree eats oxalic-containing foods. X. rutilus has been shown to be uniquely efficient in its capacity to forage for food. This ability is not diminished across a variety of different environments, including those with a poor to moderate food supply.[10]

Behavior

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Burrows

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X. rutilus are mainly solitary. They live in burrow systems with one or two adults with overlapping home areas. In times of danger unstriped ground squirrel may dive into a foreign burrow for safety. Unstriped ground squirrels permit non-resident squirrels to enter their burrows, including those of other species (X. erythropus).[3] They spend most of their waking hours outside their burrows, but utilize them for sleep and shelter from the elements. They move around quite often during the day, but remain sedentary.[11][12]

Dominance hierarchy

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Although not territorial, a dominance hierarchy exists with male squirrels being dominant over females and younger squirrels. X. rutilus demonstrate dominance via vocalization, tail displays, and physical lunges.[3][11][12]

Physiology

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Thermoregulation

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Unstriped ground squirrels generally reside in hot arid conditions and compensate by exhibiting behavioral thermoregulation. After periods of foraging in hot areas, they retreat to the shade and lie down on the shaded ground to cool off.[3][11][12]

References

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Sources

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Wikimedia Commons has media related to Xerus rutilus.
  • Thorington, R. W. Jr. and R. S. Hoffman. 2005. Family Sciuridae. pp. 754–818 in Mammal Species of the World a Taxonomic and Geographic Reference. D. E. Wilson and D. M. Reeder eds. Johns Hopkins University Press, Baltimore.
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Unstriped ground squirrel

View on Grokipedia
from Grokipedia
The unstriped ground squirrel (Xerus rutilus) is a medium-sized belonging to the family Sciuridae, endemic to and notable as the sole in its lacking the characteristic dorsal stripes found in relatives. It features coarse, tawny to reddish-brown fur, prominent white rings around the eyes, a head-body length of 200–255 mm, a tail length of 120–225 mm, and a weight ranging from 260–420 g, making it the smallest member of the genus Xerus. With a dental formula of 1/1, 0/0, 1/1, 3/3 (totaling 20 teeth), it exhibits adaptations for a lifestyle in arid environments. Native to dry savannas, subtropical or tropical dry shrublands, open plains, scrub thickets, gravel flats, and riverine areas with soft soil suitable for burrowing, X. rutilus occupies elevations from sea level to over 2,000 m across Djibouti, Eritrea, Ethiopia, Kenya, Somalia, Sudan, Tanzania, and Uganda. This species is diurnal, emerging from burrows to forage and sunbathe for up to 30 minutes daily to regulate body temperature, while retreating underground to evade predators during midday heat or threats. Omnivorous by nature, its diet consists primarily of seeds (comprising over 50% of intake), supplemented by fruits, leaves, roots, flowers, grasses, , and occasionally small vertebrates; it practices scatter hoarding to store excess food. Socially, individuals are largely solitary but form loose colonies in suitable habitats, sharing systems in family groups of up to six, with behaviors including vigilance postures and alarm calls to deter intruders. Reproduction in X. rutilus likely occurs year-round in response to resource availability, with females typically producing litters averaging two young (range 1-2); is provided solely by the mother, including and protection within burrows. Classified as Least Concern on the due to its broad distribution, presumed large population, and absence of significant threats, the unstriped ground squirrel faces no major conservation challenges, though localized degradation from or overgrazing could impact subpopulations.

Nomenclature and taxonomy

Scientific classification

The unstriped ground squirrel (Xerus rutilus) is classified within the order Rodentia, which encompasses a diverse array of rodents adapted to various ecological niches worldwide. As a member of the family Sciuridae, it shares evolutionary ties with other squirrels, particularly those in the subfamily Xerinae, known for ground-dwelling habits in arid regions. The binomial name Xerus rutilus was first described by Cretzschmar in 1828, originally under the genus Sciurus before reassignment to Xerus.
Taxonomic LevelTaxon
KingdomAnimalia
PhylumChordata
ClassMammalia
OrderRodentia
FamilySciuridae
SubfamilyXerinae
TribeXerini
GenusXerus
SpeciesXerus rutilus
This classification places X. rutilus as the sole unstriped species within the genus Xerus, distinguishing it from its striped congeners such as Xerus erythropus, which exhibit prominent dorsal stripes for camouflage in savanna habitats. The genus Xerus comprises four extant species endemic to Africa, all adapted as ground squirrels to semi-arid and arid environments through behavioral and morphological specializations. Eight subspecies of X. rutilus are currently recognized, including the nominate X. r. rutilus and X. r. dabagala. Evolutionarily, X. rutilus is part of the African ground squirrels in tribe , with fossil evidence indicating divergence during the epoch, as early records from deposits in suggest tentative ancestors of the genus. These adaptations to arid conditions, including burrowing and diurnal activity, trace back to this period of climatic drying in , contributing to the lineage's persistence in xeric ecosystems.

Common and local names

The unstriped ground squirrel (Xerus rutilus) is known in English primarily as the "unstriped ," a name that underscores its unique lack of the dorsal stripes typical of other members of the tribe. An alternative English common name is "pallid ," which highlights the ' pale tan to reddish-brown pelage. Across its East African range, the species bears several indigenous names that often evoke its coloration, structure, or terrestrial habits. In , it is called kindi or kidiri. Among Somali speakers, the name dabagalleh is used, literally meaning "possessor of a like a sheath or ," referring to the animal's distinctive bushy . In the Karamojong language of northern and , local terms include ekunyuk and ngikunyuko, while the Kiliangulu refer to it as eetata. The scientific name originates from its original description by Philipp Jakob Cretzschmar in 1828 as rutilus, where "rutilus" derives from Latin for "reddish," describing the pelage hue; it was subsequently reclassified to the genus . These common and local names frequently incorporate elements of the species' morphology or , demonstrating how in arid East African communities recognize and categorize the animal's traits.

Distribution and habitat

Geographic range

The unstriped ground squirrel (Xerus rutilus) occurs across a broad expanse of , with confirmed presence in the countries of , , , , , , , and . This distribution centers on arid and semi-arid northeastern regions, reflecting the species' adaptation to open landscapes in the and adjacent areas. The range spans from northeastern southward to northern , incorporating fragmented ecosystems typical of the Somali-Masai . Populations are patchy, concentrated in suitable semi-arid zones where suitable burrowing sites are available, though the overall extent covers a wide area without continuous occupation. Within this geographic spread, the species primarily inhabits dry s and shrublands. Historically, the distribution has remained relatively stable without evidence of major range-wide contractions, though range contraction has been noted in parts of due to displacement by the striped ground squirrel (Xerus erythropus).

Habitat preferences

The unstriped ground squirrel (Xerus rutilus) primarily inhabits dry savannas, subtropical and tropical dry shrublands, arid bushlands, and riverine zones characterized by soft soils suitable for burrowing. These environments provide the open, arid conditions essential for their lifestyle, with populations distributed across in regions supporting sparse vegetation cover. The species exhibits a strong preference for sandy or loamy soils within open grasslands featuring scattered acacia trees (Acacia spp.) and shrubs, such as Acacia-Commiphora associations, which offer moderate cover without impeding visibility or movement. Dense forests are actively avoided, as they lack the suitable soil structure and openness required for burrowing and predator detection. This habitat selection occurs across an altitudinal gradient from sea level to 2,000 meters. At the microhabitat level, unstriped ground squirrels frequently utilize areas proximal to mounds and rocky outcrops, including granitic kopjes with large boulders, for supplemental shelter in addition to their self-excavated . They also show notable tolerance for human-disturbed sites, such as agricultural fields and alluvial flats in semi-arid regions, where softer soils and proximity to sources enhance burrow stability.

Physical description

External morphology

The unstriped ground squirrel (Xerus rutilus) is characterized by its plain, unstriped pelage, distinguishing it from other African ground squirrels that possess dorsal stripes. The dorsum is typically brownish or tawny, often with a tint, while the underparts are paler and lighter in color. A prominent white ring encircles the large eyes, and there is a white patch anterior to the small, slit-like ears, enhancing facial contrast. The upper body is heavily ticked with white hairs, sometimes appearing speckled with black along the midline of the back, and coloration may vary regionally, with northern populations exhibiting a paler overall tone. The pelage is coarse and bristly, often described as "harsh-furred," which provides effective in arid, habitats. Undersides are sparsely furred, and molting occurs throughout the year without distinct seasonal patterns. The is bushy yet relatively short compared to the body length, measuring about three-quarters of the head-body length; it appears flattened due to long hairs projecting laterally, with coloration above, whitish below, and a mix of black and white hairs throughout. Head features include a long, pointed muzzle with prominent black vibrissae and moderately large ears edged with white tufts. The limbs are pale relative to the body, with large, powerful feet bearing long, straight claws adapted for burrows. Hind limbs are elongated, facilitating bounding locomotion across open terrain. Sexual dimorphism is minimal, with males and females exhibiting similar external appearance and pelage characteristics.

Size and measurements

The unstriped ground squirrel (Xerus rutilus) exhibits body dimensions typical of small to medium-sized ground squirrels within its . The head-body length measures 200–255 mm, while the tail reaches 120–225 mm in length. The hind foot length ranges from 35–60 mm, contributing to its adapted locomotion in arid environments. Adults weigh between 260 and 420 g, with individuals in some populations averaging around 315–420 g based on museum specimens. Cranial features include a braincase breadth of 24.1–25.7 mm and a length of 31.0–33.9 mm, reflecting a compact structure suited to its . Body measurements show minimal intraspecific variation across the species' range, with no significant differences noted among . in size is not pronounced.

Behavior

Social structure and dominance

The unstriped ground squirrel (Xerus rutilus) exhibits a largely solitary , typically occupying isolated systems either alone or in small groups of 1 to 6 individuals, such as a single adult male paired with 1 to 2 females or a female with her young; there are no distinct colonial or kin-based social units beyond maternal-offspring associations. These animals are non-colonial, with systems often shared opportunistically but not defended as exclusive territories. A linear exists among individuals whose home ranges overlap, characterized by stable relationships that influence access to resources like ; adult males consistently dominate females in approximately 97% of intersexual encounters, while adults dominate juveniles in all observed cases. This hierarchy is established and maintained primarily through vocal threats, such as chattering by dominants, tail-flagging displays (involving piloerection and arching of the bushy tail), and physical chases or supplanting maneuvers, with actual involving being rare and infrequent. Among females, linear rankings emerge via similar agonistic interactions, though males show less consistent hierarchical structure relative to one another due to their larger, more transient ranges; allogrooming is rare and not a prominent affiliative . Social interactions are generally infrequent and low in , with most encounters (observed in 542 cases) resolving through brief chases along paths that rarely escalate to physical contact; subordinates respond with submissive chirring vocalizations. Foraging occurs solitarily during the day, though individuals may form loose, temporary aggregations at abundant food sources like fallen ; alarm responses, including upright postures with piloerected tails, provide indirect benefits to nearby conspecifics by signaling predator presence across overlapping areas. Home ranges broadly overlap without territorial defense, averaging 7.01 ha for males (ranging 6.71–7.52 ha) and 1.37 ha for females (ranging 1.00–1.52 ha) during the active season from December to April, with males expanding their ranges further during the breeding period to increase encounter rates with females.

Burrowing and activity patterns

The unstriped ground squirrel (Xerus rutilus) constructs isolated systems that function as primary refuges, sleeping sites, and locations for . These systems typically include 2 to 6 entrances, often positioned in the shade of overhanging such as bushes or thickets, and are spatially separated from those of other individuals or groups. Adults may occupy a burrow alone or share it with one other adult, though burrows are not central to most diurnal activities beyond emergence and retreat periods. This exhibits strictly diurnal activity patterns, emerging from burrows in the morning to engage in and other behaviors before retreating at . For vigilance, individuals frequently adopt a bipedal stance by rearing up on their hind legs, which expands their to detect potential threats. Locomotion primarily involves bounding gaits suited to their open, arid habitats. The daily cycle centers on , which occupies much of the active period, particularly in open areas near ; individuals retreat to burrows or shaded bushes during midday heat to rest and continue limited on accessible resources like fruits. Unlike many temperate ground squirrels, X. rutilus does not hibernate and maintains year-round activity adapted to its semi-arid environment. To evade predators, unstriped ground squirrels produce alarm calls including chirring and chattering vocalizations, often while assuming alert postures, followed by rapid retreats into burrows. They also perch on mounds, which provide elevated vantage points for scanning the surroundings and early threat detection.

Ecology

Diet and foraging

The unstriped ground squirrel (Xerus rutilus) is an opportunistic with a diet primarily composed of matter, including seeds, leaves, fruits, stems, pods, roots, and bulbs, supplemented by . Analysis of stomach contents from individuals in northern revealed that seeds comprised approximately 53% of the volume, leaves and flowers 30%, soft fruits 11%, and 6%. Preferred plant foods include fruits from , , and species, as well as seeds from Hyphaene and . When available, cultivated crops such as millet, , peanuts, and form a significant portion of the diet, often exceeding 50% alongside dry seeds and leaves. Foraging occurs diurnally on the ground, with individuals emerging from burrows in the morning to feed in open areas before retreating to shaded bushes during midday heat to avoid predators and thermoregulatory stress. They employ forepaws to dig for buried bulbs, roots, and seeds, exhibiting high efficiency in resource extraction even under predation risk, as measured by low giving-up densities in experimental food patches. Unlike many temperate squirrels, X. rutilus engages in scatter hoarding to store food. Dietary composition varies with seasonal availability and habitat resources, shifting toward more herbaceous material and during wet periods when is abundant, while emphasizing drought-resistant seeds and roots in dry seasons. Nutritional adaptations include tolerance for plant secondary compounds such as , which do not deter . Adapted to arid environments, X. rutilus derives most of its hydration from moisture in food sources like fruits and bulbs, rarely consuming free-standing water. This high-fiber, water-efficient diet supports sustained activity in water-scarce regions without specialized digestive modifications beyond general sciurid capabilities.

Reproduction and life cycle

The unstriped ground squirrel (Xerus rutilus) breeds primarily during March and April, though breeding can occur opportunistically year-round in favorable environmental conditions, such as post-rainy periods; the exact timing remains uncertain and may vary by region. This flexibility aligns with the species' adaptation to arid habitats where resources vary seasonally. The is polygynous, with solitary females occasionally accompanied by groups of males during the breeding period; males compete for mating access through dominance displays, including piloerection and arching of the tail over the back, as briefly noted in studies of . Females give birth to litters of 1–2 altricial , with an average litter size of 2, in specialized maternity constructed at the periphery of their home range. are born hairless and helpless, dependent entirely on maternal care provided solely by the . In the life cycle, young emerge from the after about 3–4 weeks and are at 3–4 weeks of age. Juveniles remain in the maternity following , while the abandons it and returns to her original after 3–4 weeks post-emergence; dispersal occurs later as they reach independence. In the wild, lifespan is unknown, though captive records indicate up to 6 years.

Physiology

Thermoregulation

The unstriped ground squirrel (Xerus rutilus) inhabits hot, arid savannas and shrublands where ambient temperatures frequently exceed 40°C, necessitating effective to prevent . These squirrels employ a combination of behavioral and physiological mechanisms to maintain core body temperature within a viable range, allowing them to remain active during much of the day despite extreme environmental conditions. Behavioral strategies play a primary role in . During peak midday , unstriped ground squirrels retreat to burrows or shaded areas, such as under mounds or , to avoid direct solar radiation and reduce gain; this midday refuge is a key for minimizing exposure in open habitats. They use their bushy tails to shade their bodies. Additionally, after in hot open areas, individuals return to cooler shade and press their ventral surfaces against the ground to facilitate conductive loss. These behaviors collectively enable extended surface activity while conserving in resource-scarce environments. Physiological traits complement these behaviors for evaporative cooling. Unstriped ground squirrels may salivate to enhance cooling when ambient temperatures rise. Unlike some temperate ground squirrels, X. rutilus does not enter or , relying instead on these active mechanisms year-round. Daily activity patterns align closely with thermal conditions to optimize . Emergence from burrows occurs around sunrise, with foraging peaking in the cooler morning and late afternoon hours; activity ceases or shifts to shade as temperatures climb, resuming only after sunset. This bimodal pattern helps maintain body temperature stability, with squirrels tolerating brief elevations during activity but avoiding lethal extremes through timely retreats. Seasonally, burrow use intensifies during the dry period when heat stress is greatest, prolonging rest phases without entering states.

Environmental adaptations

The unstriped ground squirrel (Xerus rutilus) possesses physiological mechanisms for that are critical for survival in arid savannas and shrublands with limited free availability. It produces highly concentrated through efficient function, achieving osmolalities up to approximately 3,280 mOsm/L during dry seasons, which minimizes renal loss. Like other members of the Xerus, it exhibits minimal cutaneous loss due to the absence of sweat glands and low evaporative cooling, relying primarily on metabolic and preformed from its diet of seeds, fruits, and insects. Sensory adaptations enhance detection of resources and threats in sparse, open habitats. The species has a well-developed sense of olfaction, which aids in locating buried and detecting food sources over distances, complemented by large eyes ringed in white for improved during diurnal . Acute hearing allows for rapid response to aerial and terrestrial predators, with morphology tuned to low-frequency sounds common in windy arid environments. Immune and metabolic traits support resilience to environmental stressors in dry regions. Elevated codon usage in mitochondrial genes, such as UGC-Cys (RSCU = 1.83), promotes protein synthesis, potentially conferring resistance to from arid pathogens and . Efficient metabolic pathways, evidenced by positive selection in ND4 (ω = 1.8) and an elongated ATP6 gene (680 bp), optimize ATP production and energy use under low-water conditions, enabling sustained activity without excessive hydration needs. Kidney efficiency further aids low-water diets by maximizing solute reabsorption. Morphological features tie directly to arid survival. Strong forelimbs and robust claws facilitate burrowing in compacted, hard soils to create refuges that reduce exposure to desiccation. The dental structure, with high-crowned molars, is adapted for processing abrasive, gritty plant material common in dry landscapes, minimizing wear while extracting nutrients efficiently.

Conservation

IUCN status

The unstriped ground squirrel (Xerus rutilus) is classified as Least Concern on the (assessed in 2016) due to its wide distribution across dry savanna and shrubland habitats in and the , presumed large overall population, and absence of significant threats causing population decline. This status reflects stable population trends based on available monitoring data, and there are no identified major threats to its .

Threats and management

The unstriped ground squirrel faces primarily due to agricultural expansion in its arid range, which converts natural shrublands into croplands and disrupts connectivity between suitable patches. by in semi-arid regions further exacerbates soil degradation and vegetation loss, indirectly limiting burrow sites and foraging areas. There is no evidence of major pressure across its range, though localized opportunistic trapping occurs in parts of southern . In cultivated areas, populations experience declines from direct persecution as agricultural pests, where high densities—reaching up to 848 individuals per square kilometer in regions like —lead to crop damage on , groundnuts, yams, and , prompting control measures such as trapping or . No dedicated conservation programs target the unstriped ground squirrel, reflecting its overall low extinction risk, but it benefits incidentally from protected areas such as in and various reserves in that safeguard ecosystems. Enhanced population monitoring is recommended to track localized declines in fragmented agricultural zones and inform targeted management, such as habitat corridors or pest mitigation alternatives. The future outlook is stable globally, classified as Least Concern by the IUCN, but localized interventions are advised to address range contractions in human-modified landscapes.

References

  1. https://animaldiversity.org/accounts/Xerus_rutilus/
  2. https://www.gbif.org/species/2437455
  3. https://www.iucnredlist.org/species/23147/115167688
  4. https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=930244
  5. https://www.science.smith.edu/departments/biology/VHAYSSEN/msi/pdf/i0076-3519-370-01-0001.pdf
  6. https://a-z-animals.com/animals/xerus/
  7. https://www.researchgate.net/publication/261553918_Historical_Biogeography_and_Body_Form_Evolution_of_Ground_Squirrels_Sciuridae_Xerinae
  8. https://animalia.bio/unstriped-ground-squirrel
  9. https://www.mammaldiversity.org/taxon/1001838/
  10. https://www.researchgate.net/figure/Distribution-of-Xerus-rutilus-This-is-a-typical-species-of-Somali-Masai-savanna_fig43_335727866
  11. https://www.usgs.gov/publications/home-range-social-behavior-and-dominance-relationships-african-unstriped-ground
  12. https://www.researchgate.net/publication/303941781_Ecological_factors_affecting_the_foraging_behaviour_of_Xerus_rutilus
  13. https://tb.plazi.org/GgServer/html/064D0660FF87ED7AFF6FF6C0F635F07C
  14. https://www.researchgate.net/figure/Representatives-of-genera-in-African-bristly-ground-squirrels-Xerina-1-Atlantoxerus_fig2_287107810
  15. https://www.cokesmithwildlife.com/genus-xerus-euxerus-geosciurus-african-ground-squirrels
  16. https://academic.oup.com/jmammal/article-abstract/57/3/450/872254
  17. https://pubs.usgs.gov/publication/70119575
  18. https://journals.co.za/doi/pdf/10.10520/AJA10115498_177
  19. https://www.mdpi.com/1424-2818/17/8/538
  20. https://www.authorea.com/doi/pdf/10.22541/au.158169784.42584690
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