Squirrel Research Articles

Photographic record of Kashmir Gliding Squirrel Eoglaucomys fimbriatus (J.E. Gray, 1837) from the Gurez Valley, Jammu & Kashmir, India

Around 48 species of gliding squirrels are present in the world; found mainly in tropical regions of North America, Eurasia, and southeastern Asia. The Kashmir Gliding Squirrel Eoglaucomys fimbriatus is a rare species of rodent that belongs to the family Sciuridae. It is a nocturnal species, resting during the daytime in tree shelters and emerging at night to feed. This paper documents the direct sighting of the Kashmir Gliding Squirrel from the Gurrai Nallah, Gurez Valley of Jammu & Kashmir.

Comparative selective pressure analysis on mitochondrial protein-coding genes in flying squirrels (Pteromyini) and tree squirrels (Sciurini)

Different animal groups with varying locomotion modes may have unique energy requirements. Mitochondria produce adenosine triphosphate (ATP) and reactive oxygen species via oxidative phosphorylation to support organisms energy requirements. The tribes Pteromyini (flying squirrels) and Sciurini (tree squirrels), two closely related taxa within the family Sciuridae, exhibit distinct locomotion modes, energy requirements, and likely face different selective pressures on mitochondrial protein-coding genes (PCGs). We analysed 13 mitochondrial genome sequences from species belonging to the tribe Pteromyini and 117 from species belonging to the tribe Sciurini. Phylogenetic analysis revealed Pteromyini and Sciurini formed a sister relationship within the family Sciuridae. Among the 13 PCGs, ATP8 exhibited the highest dN/dS values, while COX1 showed the lowest. The background selection ratio (ω2) values for six genes (ND1, ND2, ND4, ATP6, ND5, and COX3) in Pteromyini were lower than the foreground selection ratio (ω0) values observed in Sciurini. A RELAX analysis revealed that CYTB, ND4, ATP6, and COX3 genes experienced intensified in selection strength. BUSTED analysis identified stronger signatures of diversifying selection in CYTB and ATP6, highlighting amino acid changes. MEME identified episodic diversifying selection at specific sites among eight PCGs. These findings revealed distinct selective pressures on PCGs in flying and tree squirrels.

Diversity, abundance and habitat association of small mammals in Maze National Park, Ethiopia

We investigated species composition, relative abundance, habitat association and density of small mammals in Maze National Park, Ethiopia. Data were collected using the capture-mark-recapture technique in three representative habitat types (grassland, bushland and riverine forest) from November 2021 to August 2022. Descriptive statistics and indices for diversity and evenness were used to analyse the data. A total of 679 rodents and insectivores were collected during a span of 2 646 trap nights. Of these, 534 (76.64%) individuals were newly captured, while 145 (23.36%) were recaptures. Overall trap success was 20.18%. Five species of rodents were captured: four from the family Muridae (Mastomys natalensis, Arvicanthis niloticus, Rattus rattus and Lemniscomys macculus) and one (Xerus rutilus) from the family Sciuridae; and one insectivore species (Elephantulus rufescens) from the family Macroscelididae. Mastomys natalensis (178; 33.3%) was the most abundant, while X. rutilus (1; 0.2%) and E. rufescens (1; 0.2%) were the least abundant. Small mammal species varied significantly with habitat types (χ2 = 6.101, df = 2, p ≤ 0.05), with the highest count in the bushland habitat (197; 36.89 %) and the lowest in riverine forest (152; 28.46%). The bushland and riverine forest habitats supported the highest (H’ = 1.04) and the lowest (H’ = 0.506) diversity of small mammal species, respectively. A relatively high number of small mammal species were caught during the wet season (n = 336) compared to the dry season (n = 198). Future studies using more trapping grids covering additional habitat types and genetic analyses for small mammal species confirmation are necessary for a better understanding of the Park’s small mammal fauna.

Evolutionary lability of food caching behaviour in mammals.

Food hoarding provides animals access to resources during periods of scarcity. Studies on mammalian caching indicate associations with brain size, seasonality and diet but are biased to a subset of rodents. Whether the behaviour is generalizable at other taxonomic scales and/or is influenced by other ecological factors is less understood. Population density may influence food caching due to food competition or pilferage, but this remains untested in a comparative framework. Using phylogenetic analyses, we assessed the role of morphology (body and brain size), climate, diet breadth and population density on food caching behaviour evolution at multiple taxonomic scales. We also used a long-term dataset on caching behaviour of red squirrels (Tamiasciurus fremonti) to test key factors (climate and population density) on hoarding intensity. Consistent with previous smaller scale studies, we found the mammalian ancestral state for food caching was larderhoarding, and scatterhoarding was derived. Caching strategy was strongly associated with brain size, population density and climate. Mammals with larger brains and hippocampal volumes were more likely to scatterhoard, and species living at higher population densities and in colder climates were more likely to larderhoard. Finer-scale analyses within families, sub-families and tribes indicated that the behaviour is evolutionary labile. Brain size in family Sciuridae and tribe Marmotini was larger in scatterhoarders, but not in other tribes. Scatterhoarding in tribe Marmotini was more likely in species with lower population densities while scatterhoarding in tribe Sciurini was associated with warmer climates. Red squirrel larderhoarding intensity was positively related to population density but not climate, implicating food competition or pilferage as an important mechanism mediating caching behaviour. Our results are consistent with previous smaller-scale studies on food caching and indicate the evolutionary patterns of mammalian food caching are broadly generalizable. Given the lability of caching behaviour as evidenced by the variability of our results at finer phylogenetic scales, comparative analyses must consider taxonomic scale. Applying our results to conservation could prove useful as changes in population density or climate may select for different food caching strategies and thus can inform management of threatened and endangered species and their habitats.

Histological Features of Olfactory Bulb Layers in the African Striped Ground ‎Squirrel (Xerus erythropus)‎

The diurnal African Striped Ground Squirrel (ASGS) (Xerus erythropus), is a member of the rodent order Rodentia and family Sciuridae. Similar to most other vertebrates, the olfactory bulbs (OB) are located most rostrally in the brain and are an integral component of the brain circuitry system responsible for the sense of smell. In this work, the layers and anatomical characteristics of OB in the ASGS were examined. Six (6) adult ASGS were sourced from villages within Zaria Local Government. They were housed in standard laboratory cages and fed with corn and carrot. Water was given ad libitum. The squirrels were euthanized via the abdomen with an injection of ketamine HCL (80mg/kg BW), followed by transcardial perfusion with10% buffered formalin. Craniotomy was carried out to expose the entire brain and the OB was carefully harvested for histological evaluation. Six layers were visible in the olfactory bulb cortex, working their way inward from the outside in. The cells observed were mitral cells, peri-glomerular, granular, and tufted cells. Interestingly, the glomerular layer was observed to be a single layer cell type which is indicative of a good olfactory acuity. It was concluded that African Striped ground squirrel’s one-layered cell thick glomerular layer is indicative of good olfaction and sense of smell giving the ASGS an advantage for navigation in search for food and protection from predation.

Complete mitogenomes of Turkish tree squirrels, Sciurus anomalus and S. vulgaris, (Sciuridae: Rodentia: Mammalia) and their phylogenetic status within the tribe Sciurini

The genus Sciurus, a member of the family Sciuridae, is widely distributed in the Holarctic region. To better understand mitogenomic characteristics and to reveal internal phylogenetic relationships of the genus, 20 complete mitogenomes of Turkish tree squirrels were successfully sequenced for the first time, including 19 for S. anomalus (from 16,505 bp to 16,510 bp) and one for S. vulgaris (16,511 bp). The mitogenomes of two species were AT-biased. All tRNAs for two species displayed a typical clover-leaf structure, except for tRNASer(AGY). The tRNA Serine1 (S1)-GCT structure lacked the dihydrouridine (DHU) loop and stem. Based on mitogenomic dataset for phylogeny of Sciurinae, phylogenetic analyses (Bayesian Inference and Maximum Likelihood) did not support monophyly of Sciurus and proposed that S. anomalus, the most basal taxa in the Sciurini tribe, had at least five mitogenome lineages, which were also supported by network analysis. The dissimilarities among the five lineages of S. anomalus ranged from 0.0042 (0.42%) to 0.0062 (0.62%) using K2P sequence pairwise distances. In addition to this mitogenomic analysis result, phylogenetic analyses using the CYTB + D-loop dataset proposed the existence of at least nine lineages for S. anomalus, which was different than those of the previous studies. The current study proposed that the use of mitogenomic data for reconstructing the phylogeny of Turkey’s Sciurus holds an important value for revealing evolutionary relationships.

Dietary Patterns Suggest West Virginia Bobcats Are Generalist Carnivores

Abstract The proportion and diversity of prey species consumed by bobcats Lynx rufus are often correlated with prey abundances, individual skill level, environmental conditions, and habitat quality. Bobcats generally consume prey species that rely on mast—the fruits of trees—for basic life-history requirements. In West Virginia forests, many mast-producing tree species have declined over the past 40 y, yet the last known study on bobcat diet in the state was in 1977. Thus, we need current data to understand the effects of forest compositional changes on bobcat dietary patterns. We evaluated stomach contents of 300 bobcats collected over the 2014–2015 (n = 150) and 2015–2016 (n = 150) hunting and trapping seasons in West Virginia. Simpson's index of diversity indicated an 87% probability that two randomly selected prey items belong to different species, supporting the idea of bobcats as generalist carnivores. White-tailed deer (hereafter deer) Odocoileus virginianus (32%), mice and rats (families Cricetidae, Dipodidae, and Muridae; 30.7%), rabbits (family Leporidae; 21.3%), Virginia opossum Didelphis virginiana (18.7%), and squirrels (family Sciuridae; 17.3%) occurred most frequently. We found 92% dietary overlap between sexes and 35% between stage classes. Deer, opossum, and raccoon Procyon lotor occurred more frequently in males, whereas rabbits occurred more frequently in females. Deer occurred more frequently in adults; raccoons in yearlings; and mice and rats in juveniles. Overall occurrence of deer (−17.1%), rodents (order Rodentia; −9.5%), opossum (+13.5%), and raccoon (+5.1%) differed significantly between the 1977 study and this study, which may allude to changes in the abundance of mast-dependent prey species over time. Similarly, hard mast (i.e., nuts) production had a significant interaction effect with study season on the overall occurrence of squirrels in bobcat diets. By improving our understanding of bobcat trophic interactions, we can better manage their populations and ecological communities by managing for the dietary requirements of their common prey species.

MORPHOLOGICAL CHARACTERIZATION OF PLANTAIN SQUIRREL (Callosciurus notatus) SPERM

The plantain squirrel (Callosciurus notatus) is a rodent of the family Sciuridae. The population of plantain squirrels in Indonesia has decreased every year. The 2019 Checklist of the Mammals of Indonesia reports that the plantain squirrel is in a low concentration status; thus, accelerated efforts in wildlife conservation, including integrating technology with conservation efforts, are necessary. This study aims to determine the morphological characteristic of the plantain squirrel spermatozoa. This research consisted of several stages: anesthesia of animal samples, surgery, a maceration method, observation of the spermatozoa morphology using William's staining, and morphometry of sperm using ImageJ 1.46r software. The results show that the plantain squirrel sperm has a slightly flat head shape, falciform with one apical hook, and a not too long tail. The average sperm head length is 1.87 ± 0.30 µm, the average sperm tail length is 5.48 ± 0.95 µm.

Editorial: Ecological, Behavioral and Genomic Consequences in the Rodent Family Sciuridae: Why Are Squirrels So Diverse?

Editorial: Ecological, Behavioral and Genomic Consequences in the Rodent Family Sciuridae: Why Are Squirrels So Diverse?

Notes on mammals and avifauna at FRIM Campus, Selangor, Peninsular Malaysia

Forest Research Institute Malaysia (FRIM) was established in 1985, and later in 2009, FRIM was awarded as Natural Heritage of Malaysia. Researchers of FRIM Zoology Branch conducted continuous monitoring of faunal diversity, especially on mammal and bird groups. The study’s objective is to illustrate the diversity of mammals and birds found within the FRIM Campus. There are 62 species of mammals from 18 families with highest species recorded (10spp) was from family Vespertilionidae, followed by family Sciuridae and Hipposideridae with nine and seven species, respectively. A total of 233 species of birds from 58 families were recorded up to date of which 173 are resident, and 28 are migratory. Pycnonotidae or Bulbuls are the family with highest number of species (18spp), followed by family Cuculidae (14spp) and Rallidae (13spp). Although FRIM used to be an agricultural and mining area, it is believed that the faunal composition is "returning" to this forest since it was reforested back in the early 1900s. Connected to Bukit Lagong Forest Reserve, this 544.3-ha campus is blessed as it provides a natural habitat and ensures the continuity of vast faunal diversity.

Assessing the occurrence of the novel zoonotic variegated squirrel bornavirus 1 in captive squirrels in Germany -A prevalence study.

The newly described zoonotic variegated squirrel bornavirus 1 (VSBV-1) in German squirrel holdings has been associated with the death of three private owners and one zoo animal caretaker (confirmed cases). Epidemiological investigations were severely impeded by the general lack of data on holdings of the putative reservoir hosts, the family Sciuridae. To fill this lack of data for detailed epidemiological investigations of the captive squirrel population, a register of private and zoological squirrel holdings was established. The findings show a broad variety of kept species and their frequency distribution. By contacting the different stakeholders via Web-based social groups and societies, information passed in both directions so that disease awareness could be raised and participants could be recruited for further studies. Cross-sectional studies revealed a prevalence of VSBV-1-positive subpopulations of 0% (95% CI 0%-6.2%) among private squirrel collections and 1.9% (95% CI: 0%-9.9%) among zoos in Germany. The approach presented here can be transferred to other populations of non-traditional pets, which may be equally difficult to monitor, in the case of an emerging zoonotic infectious disease.

Search for polyoma-, herpes-, and bornaviruses in squirrels of the family Sciuridae

BackgroundSquirrels (family Sciuridae) are globally distributed members of the order Rodentia with wildlife occurrence in indigenous and non-indigenous regions (as invasive species) and frequent presence in zoological gardens and other holdings. Multiple species introductions, strong inter-species competition as well as the recent discovery of a novel zoonotic bornavirus resulted in increased research interest on squirrel pathogens. Therefore we aimed to test a variety of squirrel species for representatives of three virus families.MethodsSeveral species of the squirrel subfamilies Sciurinae, Callosciurinae and Xerinae were tested for the presence of polyomaviruses (PyVs; family Polyomaviridae) and herpesviruses (HVs; family Herpesviridae), using generic nested polymerase chain reaction (PCR) with specificity for the PyV VP1 gene and the HV DNA polymerase (DPOL) gene, respectively. Selected animals were tested for the presence of bornaviruses (family Bornaviridae), using both a broad-range orthobornavirus- and a variegated squirrel bornavirus 1 (VSBV-1)-specific reverse transcription-quantitative PCR (RT-qPCR).ResultsIn addition to previously detected bornavirus RNA-positive squirrels no more animals tested positive in this study, but four novel PyVs, four novel betaherpesviruses (BHVs) and six novel gammaherpesviruses (GHVs) were identified. For three PyVs, complete genomes could be amplified with long-distance PCR (LD-PCR). Splice sites of the PyV genomes were predicted in silico for large T antigen, small T antigen, and VP2 coding sequences, and experimentally confirmed in Vero and NIH/3T3 cells. Attempts to extend the HV DPOL sequences in upstream direction resulted in contiguous sequences of around 3.3 kilobase pairs for one BHV and two GHVs. Phylogenetic analysis allocated the novel squirrel PyVs to the genera Alpha- and Betapolyomavirus, the BHVs to the genus Muromegalovirus, and the GHVs to the genera Rhadinovirus and Macavirus.ConclusionsThis is the first report on molecular identification and sequence characterization of PyVs and HVs and the detection of bornavirus coinfections with PyVs or HVs in two squirrel species. Multiple detection of PyVs and HVs in certain squirrel species exclusively indicate their potential host association to a single squirrel species. The novel PyVs and HVs might serve for a better understanding of virus evolution in invading host species in the future.

A Game of Fox & Squirrels by Jenn Reese

A Game of Fox & Squirrels by Jenn Reese

Marmots

Walter Arnold introduces the biology of marmots.

Discovery and description of a mysterious Asian flying squirrel (Rodentia, Sciuridae, Biswamoyopterus) from Mount Gaoligong, southwest China.

The flying squirrels of the tribe Pteromyini (Family Sciuridae) currently include 15 genera of which the genus Biswamoyopterus comprises two recognized species, B.biswasi Saha, 1981 and B.laoensis Sanamxay et al., 2013. These two species were each described from only one specimen that are separated from each other by 1,250 kilometres in southern Asia, where they occur in northeast India and central Lao PDR respectively. In 2017 and 2018, two specimens of Biswamoyopterus were discovered from Mount Gaoligong, west Yunnan province, southwest China (between the type locality of the two recognized species). This study aimed to evaluate the taxonomic status of these two newly acquired specimens of Biswamoyopterus by comparing their morphology with the two described species of the genus. The results of this study showed that the specimens from Yunnan province (China) differed from both B.laoensis and B.biswasi in both pelage colour and craniology, and should be recognised as a distinct species, B.gaoligongensissp. nov., which is formally described here. This study contributes to the understanding of the flying squirrels of southern Asia and identifies an additional species that appears to be endemic to southwest China; however, more research is required to provide details of its ecology, distribution, and conservation status.

Optimal Design of Squirrel Cage Induction Motor Using Multi-Objective Salp Swarm Algorithm

Optimal Design of Squirrel Cage Induction Motor Using Multi-Objective Salp Swarm Algorithm

Prevalence and virulence factors of coagulase negative Staphylococcus causative of prosthetic joint infections in an orthopedic hospital of Mexico.

To determine the prevalence and virulence factors of coagulase-negative Staphylococci (CNS) in prosthetic joint infections (PJI). CNS were isolated of 66 hip and knee PJI from Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, México City. Antimicrobial susceptibility and biofilm formation in CNS were determined; icaADBC, aap, bap and embp genes were determined by PCR. Staphylococcus and Staphylococcus hominis were the most prevalent with 82 y 80% respectively. Staphylococcus lugdunensis, Staphylococcus haemolyticus, Staphylococcus capitis, Staphylococcus caprae, Staphylococcus sciuri and Staphylococcus lentus were less frequent. The majority of isolates were resistant to β-lactam antibiotics, fluoroquinolone, and erythromycin. 41% of CNS were biofilm former and 59% were non-biofilm former (p = 0.0551). Biofilm former Staphylococcus epidermidis showed a high presence of icaADBC, aap and embp operons compared to the non-biofilm former isolates (p < 0.05). In contrast, non-S. epidermidis CNS had only the aap gen. S. haemolyticus, S. sciuri and S. lentus are new isolates of PJI not previously reported with virulence factors similar to CNS isolates.

Anatomical and Histological Structure of Reproductive Organs in Male Flying Squirrel Hylopetes Lepidus (Horsfield, 1822)

Flying squirrel (Hylopetes lepidus) is an Eutherial mamal (placental mammal), belong to the order Rodentia and belong to the family Sciuridae. Hylopetes lepidus had gray cheek as its unique characteristics. The reproductive organs are the key to success in maintaining the new descendants. Male reproductive organs will produce the male sex cells or spermatozoa. The purpose of the research is to examine the anatomical structure, morphometry, histomorphometry, and histological structure of male reproductive organs (penis, testicle, vas deferens, bulbouretralis gland, prostate and seminal vesicles) of Hylopetes lepidus. The method used in examining histological characteristics is Hematoxyin–Eosin staining method. The histological structure of reproductive organs were observed using optilab microscope. The results of the study showed that the adult male flying squirrel weighed 104.28 ± 0.64 gram. Anatomically, it has oval white reddist testicle. The testicle is located side out of the body cavity in the scrotum. Morphometric observation testicular showed that the right testes has volume 0.35 ± 0.07 ml, and the left has volume 0.35 ± 0.07 ml, weight of the right testicular 0.19 ± 0.01 gram, weight of the left testicular 0.18 ± 0.01 gram, diameter of the right testicular 6.35 ± 0.21 mm, diameter of the left testicular 6.35 0.21 mm, short diameter of the right testicular 3.45 ± 0.21 mm, and short diameter of the left testicular 3.45 ± 0.21 mm. The diameter of tubulus seminiferus 261,4 ± 0.14 μm. The conclusion of this study compared to rodentia other testicular Hylopetes lepidus has a unique testicular bound by the connective tissue in the scrotum so that testicular included in class permanent descending testicular. The rhombus of the prostate gland are blunt, while histologically the sertoli cells in the seminiferus tubule shaped elongated, while in morphometry penis Hylopetes lepidus relatively longer than Mus musculus.

Feeding habits of the Asiatic red-bellied squirrel Callosciurus erythraeus introduced in Argentina

Fil: Zarco, Agustin. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Aridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Aridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Aridas; Argentina

Urocitellus parryii (Rodentia: Sciuridae)

Urocitellus parryii (Richardson, 1825) is a high-latitude sciurid known as the Arctic ground squirrel. The largest of 12 species in the genus Urocitellus, its range extends farther north than any other species of squirrel. It is also the only member of family Sciuridae with a Holarctic distribution. U. parryii is colonial and a conspicuous inhabitant of tundra, meadows, and boreal forests across large tracts of Canada, Alaska, and eastern Siberia. Although the subject of significant research in some parts of its geographic range, aspects of U. parryii biology remain understudied in others, a trend that further characterizes its representation in museum collections both spatially and temporally. Although U. parryii is not currently of conservation concern (listed as “Least Concern” by the International Union for Conservation of Nature and Natural Resources), filling remaining knowledge gaps will be an important component of continued persistence given predicted scenarios of environmental change.