Use of visual cues in foraging by a diurnal herbivore, Belding's ground squirrel

1998 ◽  
Vol 76 (9) ◽  
pp. 1766-1770 ◽  
Author(s):  
Richard D Duncan ◽  
Stephen H Jenkins
Keyword(s):  
Ground Squirrel ◽  
Visual Cues ◽  
Growing Season ◽  
Ground Squirrels ◽  
Foraging Efficiency ◽  
Natural Conditions ◽  
Spermophilus Beldingi ◽  
Bait Stations

Ground squirrels' vision has been fairly well characterized, but whether they actually use vision in foraging has not been demonstrated. Belding's ground squirrels (Spermophilus beldingi) were allowed to forage under natural conditions for experimental bait stations to test the hypothesis that they can learn to use visual cues to forage more efficiently. Bait stations with visual cues were more likely to be found, and were found more quickly, than controls. Bait stations in taller and (or) denser vegetation were less likely to be found, suggesting that the value of visual cues may change during the growing season. Visual cues can be used to increase foraging efficiency, but other cues are probably used as well.

Ketone body metabolism in a ground squirrel during hibernation and fasting

1985 ◽  
Vol 249 (4) ◽  
pp. R462-R470 ◽  
Author(s):  
B. L. Krilowicz
Keyword(s):  
Energy Source ◽  
Glucose Uptake ◽  
Ground Squirrel ◽  
Ketone Body ◽  
Glucose Utilization ◽  
Ground Squirrels ◽  
Body Protein ◽  
Muscle Tissues ◽  
Spermophilus Beldingi

Hibernating Belding's ground squirrels (Spermophilus beldingi) are ketotic relative to fed nonhibernators. Muscles from torpid individuals, when incubated in media containing physiological concentrations of glucose and ketone, show reduced uptake of glucose in the presence of ketone. The magnitude of the reduction is dependent on ketone concentration and reaches 60% in heart and 100% in pectoralis at 1.4 mM ketone. Fasted squirrels are also ketotic. However, ketone does not reduce glucose uptake in muscles from fed or fasted animals. Glucose utilization by muscles decreases during a long-term fast, but the reduction is independent of ketone. Thus both a long-term fast and hibernation lead to changes in muscle tissues that decrease their reliance on glucose as an energy source. Ketosis leads to glucose sparing during hibernation, whereas muscle glucose utilization is decreased independently of ketone during a fast. The glucose sparing achieved in both hibernation and fasting leads to conservation of body protein, the major source of gluconeogenic precursors in fasting mammals.

Adaptations for hibernation in the depot fats of a ground squirrel (Spermophilus beldingi)

1991 ◽  
Vol 69 (11) ◽  
pp. 2707-2711 ◽  
Author(s):  
Craig L. Frank
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Melting Point ◽  
Ground Squirrel ◽  
Unsaturated Fatty Acids ◽  
Ground Squirrels ◽  
Body Temperatures ◽  
Melting Points ◽  
Spermophilus Beldingi ◽  
Free Ranging

Ground squirrels are small herbivores that hibernate during winter. The ecological–nutritional limitations on hibernation are virtually unknown, but one constraint may be the melting point of stored fat. Lipids must be fluid to be metabolizable, and body temperatures maintained during hibernation are usually 30 °C below the melting point of typical mammalian fats. Fats containing greater amounts of unsaturated fatty acids, however, have correspondingly lower melting points. White adipose tissue was sampled from free-ranging Belding's ground squirrels, Spermophilus beldingi, during both the summer and fall. The lipids were twice as unsaturated as those of other rodent species, most of the increased unsaturation being due to the accumulation of plant-produced polyunsaturated fatty acids derived from the animals' diet. The melting points of S. beldingi fats were consequently 25 °C lower than those of other mammals. These results suggest that ground squirrels may depend upon their plant diet for the polyunsaturates necessary to produce the lipids with low melting points that are needed for hibernation.

Social behaviour of the golden-mantled ground squirrel (Spermophilus lateralis)

1985 ◽  
Vol 63 (11) ◽  
pp. 2529-2533 ◽  
Author(s):  
Jean Ferron
Keyword(s):  
Social Interactions ◽  
Rocky Mountains ◽  
Ground Squirrel ◽  
Ground Squirrels ◽  
Agonistic Interactions ◽  
Natural Conditions ◽  
Spermophilus Lateralis ◽  
The Social ◽  
Age And Sex

The social interactions of golden-mantled ground squirrels (Spermophilus lateralis) observed during a 2-year study in the Rocky Mountains of Alberta under natural conditions are described and quantitatively analyzed. Agonistic interactions were common for all age and sex groups, except among littermates before dispersal. Among adults, cohesive and recognitive behaviours were restricted almost exclusively to male–female interactions. For young, cohesive and recognitive behaviours occurred with other young (mainly littermates) and with the mother. This species can be categorized as "asocial" according to G. R. Michener's classification of social organization in ground squirrels.

scholarly journals EXPRESS: Two Variations and One Similarity in Memory Functions Deployed by Mice and Humans to Support Foraging

2021 ◽  
pp. 174702182110105
Author(s):  
Spencer Talbot ◽  
Todor Gerdjikov ◽  
Carlo De Lillo
Keyword(s):  
Working Memory ◽  
Brain Function ◽  
Visual Cues ◽  
Brain Structures ◽  
Human Cognition ◽  
Foraging Efficiency ◽  
Long Term Memory ◽  
Memory Functions ◽  
Term Memory

Assessing variations in cognitive function between humans and animals is vital for understanding the idiosyncrasies of human cognition and for refining animal models of human brain function and disease. We determined memory functions deployed by mice and humans to support foraging with a search task acting as a test battery. Mice searched for food from the top of poles within an open-arena. Poles were divided into groups based on visual cues and baited according to different schedules. White and black poles were baited in alternate trials. Striped poles were never baited. The requirement of the task was to find all baits in each trial. Mice’s foraging efficiency, defined as the number of poles visited before all baits were retrieved, improved with practice. Mice learnt to avoid visiting un-baited poles across trials (Long-term memory) and revisits to poles within each trial (Working memory). Humans tested with a virtual-reality version of the task outperformed mice in foraging efficiency, working memory and exploitation of the temporal pattern of rewards across trials. Moreover, humans, but not mice, reduced the number of possible movement sequences used to search the set of poles. For these measures interspecies differences were maintained throughout three weeks of testing. By contrast, long-term-memory for never-rewarded poles was similar in mice and humans after the first week of testing. These results indicate that human cognitive functions relying upon archaic brain structures may be adequately modelled in mice. Conversely, modelling in mice fluid skills likely to have developed specifically in primates, requires caution.

Temperature and the Regulation of Enzyme Activity in the Hibernator. Isoenzymes of Liver Pyruvate Kinase from the Hibernating and Non-hibernating Arctic Ground Squirrel

1974 ◽  
Vol 52 (10) ◽  
pp. 894-902 ◽  
Author(s):  
Hans W. Behrisch
Keyword(s):  
Molecular Weight ◽  
Pyruvate Kinase ◽  
Wide Temperature Range ◽  
Ground Squirrel ◽  
Energy Charge ◽  
High Energy ◽  
Ground Squirrels ◽  
The Arctic ◽  
Arctic Ground Squirrel ◽  
Temperature Range

Liver of the hibernating (H) Arctic ground squirrel (Citellus undulatus) contains a single species of pyruvate kinase (PyK) that is distinct from the single isoenzyme of pyK observed in the non-hibernating (NH) ground squirrel, which has been previously described (Behrisch &Johnson (1974) Can. J. Biochem. 52, 547–559). The H-PyK has a pI value of 5.7 and a molecular weight of 241 000 – 243 000. Affinity of the H-PyK for the substrates phosphoenolpyruvate (PEP) and ADP is not affected by changing temperature. It is argued that this stability of the apparent Km's for substrate over a wide temperature range permits the hibernator to take advantage of the Q10 effect in maintaining a low rate of the PyK reaction. Similarly, affinity of H-PyK for the allosteric activator fructose-1,6-phosphate (FDP) and the inhibitor ATP is also conspicuously independent of temperature, suggesting a fine stoichiometry in the relative concentrations of the regulatory ligands in control of H-PyK over a wide temperature range. Further, affinity of H-PyK for the inhibitor ATP is about three- to fourfold lower than that of the NH-PyK, a condition that would favor the maintenance of a high energy charge in the hibernating liver cell. ATP apparently inhibits PyK by causing a dissociation of the enzyme molecule into two "halves" of about 110 000 molecular weight each. This dissociation is offset and reversed by FDP. Removal of the ATP by dialysis does not of itself result in a reassociation of the PyK "halves"; FDP and/or the substrates are required for the two subunits of PyK to reassociate. As the apparent Ki of H-PyK for ATP is higher than that of NH-PyK, substantially higher concentrations of ATP are required to effect the dissociation of H-PyK. Similarly, elevated concentrations of FDP are required to offset the ATP-caused dissociation of the H-PyK.Hibernating Arctic ground squirrels that are preparing to emerge finally from the hibernating state already possess substantial activities of the NH-PyK isoenzyme. This suggests that the animal "anticipates" its transition from one metabolic state from another. On the basis of these data a formal mechanism is proposed for the regulation of liver PyK in the Arctic ground squirrel in both the non-hibernating and hibernating states.

Body fat influences sexual maturation in captive male Belding's ground squirrels

1988 ◽  
Vol 66 (7) ◽  
pp. 1620-1625 ◽  
Author(s):  
Warren G. Holmes
Keyword(s):  
Body Fat ◽  
Sexual Maturation ◽  
Serum Testosterone ◽  
Ground Squirrels ◽  
Constant Darkness ◽  
Physiological Indicators ◽  
Abundant Food ◽  
Cold Room ◽  
Fat Stores ◽  
Spermophilus Beldingi

The influence of white adipose tissue on sexual maturation was investigated in captive-born male Belding's ground squirrels (Spermophilus beldingi). Juveniles were given abundant food during the summer and by fall achieved prehibernation body masses approximating those of sexually mature males. Immediately before being placed in a cold room (5–8 °C, constant darkness) for a 7-month hibernation period, fat was surgically removed (lipectomy) or left intact (sham lipectomy). The following spring, paired testes mass, serum testosterone, and spermatogenesis were monitored, mating tests were conducted, and body fat levels were determined. All three physiological indicators of reproductive status were significantly higher in sham-lipectomized than in lipectomized males, only sham-lipectomized males inseminated females, and body fat levels were significantly higher in sham-lipectomized than in lipectomized males. Thus, sexual maturation was accelerated in male Belding's ground squirrels by providing juveniles abundant food so they achieved body masses typical of adults; body fat was essential for accelerated development. In nature, males may forego reproductive development until they can acquire adequate fat stores to survive hibernation and activate their reproductive system and until they gain social experience important in male–male competition for mates.

A comparative study of scent-gland location and related behaviour in some northwestern nearctic ground squirrel species (Sciuridae): an evolutionary approach

1976 ◽  
Vol 54 (8) ◽  
pp. 1294-1306 ◽  
Author(s):  
V. Keith Kivett ◽  
Jan O. Murie ◽  
André L. Steiner
Keyword(s):  
Ground Squirrel ◽  
Scent Marking ◽  
Ground Squirrels ◽  
Scent Gland ◽  
Anal Glands ◽  
Greeting Behavior ◽  
Mouth Corner ◽  
Northwestern North America ◽  
Gland Development ◽  
Dorsal Gland

Location and hisiology of integumentary glands were investigated in six species of ground squirrels of the genus Spermophilus found in northwestern North America; S. columbianus, S. undulatus, S. richardsonii, S. tridecemlineatus, S. lateralis, and S. franklinii. Among these species, glands in oral, dorsal, and anal regions were structurally similar. Locations of oral and anal glands were identical but location of individual glands in dorsal-gland fields varied considerably. Gland development was greater in S. columbianus and S. undulatus and least in S. franklinii. Active scent marking was most frequent and extensive in S. columbianus and S. undulatus, less frequent in S. lateralis and S. tridecemlineatus, and absent in S. franklinii. In most instances, greeting behavior (which is focused on the mouth-corner oral-gland area) and the degree of sociality paralleled levels of scent marking. A hypothetical scheme of development or scent marking in relation to habitat and social organization is presented. This scheme fits, in general, classical interpretations of phylogeny.

Seasonal effects of food provisioning on body fat, insulin, and corticosterone in free-living juvenile Belding's ground squirrels (Spermophilus beldingi)

2002 ◽  
Vol 80 (2) ◽  
pp. 366-371 ◽  
Author(s):  
Scott Nunes ◽  
Eva-Maria Muecke ◽  
Kay E Holekamp
Keyword(s):  
Body Fat ◽  
Plasma Insulin ◽  
Plasma Concentrations ◽  
Plasma Corticosterone ◽  
Ground Squirrels ◽  
Seasonal Effects ◽  
Free Living ◽  
Active Season ◽  
Extra Food ◽  
Spermophilus Beldingi

We evaluated the relationship between body fat and the metabolic hormones insulin and corticosterone in free-living juvenile Belding's ground squirrels (Spermophilus beldingi). Some free-living juveniles were provisioned with extra food high in fat and calories, and unprovisioned juveniles were used as controls. Body fat (as a percentage of body mass) of squirrels was regularly evaluated using non-invasive methods. Blood samples were also regularly collected from juveniles and assayed for plasma concentrations of insulin and corticosterone. Provisioned juveniles were fatter than unprovisioned juveniles during most of the active season, but differences in body fat disappeared near the end of summer as juveniles began fattening for hibernation. Thus, our data indicate that although body fat may fluctuate with energy availability early in the active season, it is regulated at precise levels as squirrels prepare for winter. Plasma corticosterone concentrations did not differ between provisioned and unprovisioned juveniles. However, plasma insulin concentrations were greater in provisioned than in unprovisioned juveniles early in the summer. Differences in insulin concentrations disappeared later in the active season, just prior to the disappearance of differences in body fat. Moreover, plasma insulin concentrations were significantly correlated with subsequent changes in body fat. Thus, our data suggest a link between insulin and seasonal regulation of body fat in juvenile S. beldingi.

Ancient DNA reveals northwest range extension of Richardson’s ground squirrel (Urocitellus richardsonii) into northeastern British Columbia, Canada, during the Late Pleistocene

2020 ◽  
Vol 57 (7) ◽  
pp. 855-866
Author(s):  
Thomas C.A. Royle ◽  
Dongya Y. Yang ◽  
Jonathan C. Driver
Keyword(s):  
British Columbia ◽  
Ancient Dna ◽  
Ground Squirrel ◽  
Mitochondrial Control Region ◽  
Archaeological Site ◽  
Ground Squirrels ◽  
Vegetation Communities ◽  
Peace River ◽  
River Region ◽  
Urocitellus Richardsonii

Ancient DNA was extracted from 12 500 to 10 500 year old ground squirrel bones from Tse’K’wa, an archaeological site in the Peace River region of northeastern British Columbia, Canada. Analysis of mitochondrial DNA from seven individuals demonstrates that all are Urocitellus richardsonii (Richardson’s ground squirrel), a species not found in the region today. Phylogenetic and sequence analyses indicate these individuals share a previously undocumented mitochondrial control region haplotype that is most closely related to haplotypes observed in modern specimens from Saskatchewan and Montana. At the end of the Pleistocene these ground squirrels extended their range north and west into open vegetation communities that developed when ice sheets melted and glacial lakes drained. They were subsequently extirpated from the Peace River region when forests replaced earlier pioneering vegetation communities.

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