Hunting Techniques and Tool Use by North American Badgers Preying on Richardson's Ground Squirrels

Michener, Gail R.

doi:10.1644/bns-102

Cited by 43 publications

(26 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By a comparison of mass-normalized values, power capacity of badgers (Moore et al, 2013) exceeds that of the same muscles in groundhogs, and yet no badger forelimb muscle is capable of markedly high power output as estimated for some hindlimb muscles of cursorial mammals (Williams et al, 2007a;Williams et al, 2008). In addition to digging shallow burrows for shelter, American badgers actively hunt ground-dwelling rodents by rapid excavation of their burrows (Michener, 2004), whereas as groundhogs may burrow at a slower rate to dig deeper, morecomplex burrow systems. Therefore, differences in digging strategy may reflect selection for differences in muscle power capacity and fossorial ability between these two scratch-digging species.…”

Section: Research Articlementioning

confidence: 93%

Forelimb muscle architecture and myosin isoform composition in the groundhog (Marmota monax)

Rupert

Rose

Organ

et al. 2014

Journal of Experimental Biology

View full text Add to dashboard Cite

Scratch-digging mammals are commonly described as having large, powerful forelimb muscles for applying high force to excavate earth, yet studies quantifying the architectural properties of the musculature are largely unavailable. To further test hypotheses about traits that represent specializations for scratch-digging, we quantified muscle architectural properties and myosin expression in the forelimb of the groundhog (Marmota monax), a digger that constructs semi-complex burrows. Architectural properties measured were muscle moment arm, muscle mass (MM), belly length (ML), fascicle length (l F ), pennation angle and physiological cross-sectional area (PCSA), and these metrics were used to estimate maximum isometric force, joint torque and power. Myosin heavy chain (MHC) isoform composition was determined in selected forelimb muscles by SDS-PAGE and densitometry analysis. Groundhogs have large limb retractors and elbow extensors that are capable of applying moderately high torque at the shoulder and elbow joints, respectively. Most of these muscles (e.g. latissimus dorsi and pectoralis superficialis) have high l F /ML ratios, indicating substantial shortening ability and moderate power. The unipennate triceps brachii long head has the largest PCSA and is capable of the highest joint torque at both the shoulder and elbow joints. The carpal and digital flexors show greater pennation and shorter fascicle lengths than the limb retractors and elbow extensors, resulting in higher PCSA/MM ratios and force production capacity. Moreover, the digital flexors have the capacity for both appreciable fascicle shortening and force production, indicating high muscle work potential. Overall, the forelimb musculature of the groundhog is capable of relatively low sustained force and power, and these properties are consistent with the findings of a predominant expression of the MHC-2A isoform. Aside from the apparent modifications to the digital flexors, the collective muscle properties observed are consistent with its behavioral classification as a lessspecialized burrower and these may be more representative of traits common to numerous rodents with burrowing habits or mammals with some fossorial ability.

show abstract

Section: Research Articlementioning

confidence: 93%

Forelimb muscle architecture and myosin isoform composition in the groundhog (Marmota monax)

Rupert

Rose

Organ

et al. 2014

Journal of Experimental Biology

View full text Add to dashboard Cite

show abstract

“…genetically hard-wired), as opposed to those that require extensive learning and social input, assuming ecological learning opportunities are present. For instance, North American badgers (Taxidea taxus) frequently capture hibernating squirrels underground and are morphologically and behaviourally specialized to excavate burrow systems by the movement of soil [62]. Hence, the use of soil to plug openings into burrow systems occupied by ground squirrels may be considered an idiosyncratic expression of their normal behaviour, also because opportunities for social transmission are rare.…”

Section: (B) Phenotypic Biasesmentioning

confidence: 99%

If at first you don't succeed… Studies of ontogeny shed light on the cognitive demands of habitual tool use

Meulman

Seed

Mann

2013

Phil. Trans. R. Soc. B

View full text Add to dashboard Cite

Many species use tools, but the mechanisms underpinning the behaviour differ between species and even among individuals within species, depending on the variants performed. When considering tool use ‘as adaptation’, an important first step is to understand the contribution made by fixed phenotypes as compared to flexible mechanisms, for instance learning. Social learning of tool use is sometimes inferred based on variation between populations of the same species but this approach is questionable. Specifically, alternative explanations cannot be ruled out because population differences are also driven by genetic and/or environmental factors. To better understand the mechanisms underlying routine but non-universal (i.e. habitual) tool use, we suggest focusing on the ontogeny of tool use and individual variation within populations. For example, if tool-using competence emerges late during ontogeny and improves with practice or varies with exposure to social cues, then a role for learning can be inferred. Experimental studies help identify the cognitive and developmental mechanisms used when tools are used to solve problems. The mechanisms underlying the route to tool-use acquisition have important consequences for our understanding of the accumulation in technological skill complexity over the life course of an individual, across generations and over evolutionary time.

show abstract

“…I obtained longitudinal records on the response of freeliving Richardson's ground squirrels to eggs by observing adults that were individually recognizable from dye marks on the fur and that were under daily observation throughout the active season as part of on-going long-term ecological and behavioural studies in a grassland site in southern Alberta, Canada (49°52′N, 112°43′W; elevation 870 m), (Michener 2002(Michener , 2004. Various small passerines that nest on the ground or in low shrubs frequented the site, but none had nested in the home ranges of squirrels chosen as subjects within the lifetimes of those squirrels and no large ground-nesting birds nested on the site.…”

Section: Behavioural Observationsmentioning

confidence: 99%

Limits on egg predation by Richardson's ground squirrels

Michener¹

2005

Can. J. Zool.

View full text Add to dashboard Cite

To test the inference, arising from circumstantial evidence, that Richardson's ground squirrels (Spermophilus richardsonii (Sabine, 1822)) frequently depredate eggs of greater sage-grouse (Centrocercus urophasianus (Bonaparte, 1827)), gape size was measured and the response of free-living squirrels to three sizes of eggs was observed. Maximum gape measured on carcasses was 26 mm and functional gape assessed from tooth imprints in artificial clay eggs was 17 mm. Squirrels left imprints in 46 of 110 clay eggs, but whether tested with domestic fowl (Gallus gallus (L., 1758)) or ring-necked pheasant (Phasianus colchicus L., 1758) eggs that approximated the maximum width of sagegrouse eggs or with much smaller Japanese quail (Coturnix japonica Temminck and Schlegel, 1849) eggs that approximated maximum gape, no squirrels (28 adults and at least 28 juveniles) spontaneously depredated eggs, even after multiple exposures. When re-tested with damaged eggs, 15 of 16 adult females scavenged contents, though usually not on their first exposure. After scavenging damaged eggs, 2 of 12 squirrels opened a few intact eggs, but only quail eggs and usually only if the shell was rough. Although Richardson's ground squirrels are potential scavengers of large damaged eggs and likely they could depredate small eggs, the inference from circumstantial evidence that they are major predators of greater sage-grouse eggs remains unsubstantiated.Résumé : Des mesures de la taille de l'ouverture de la bouche des spermophiles de Richardson (Spermophilus richardsonii (Sabine, 1822)) et l'observation de la réaction des spermophiles en liberté à trois tailles d'oeufs ont servi à véri-fier la déduction faite à partir de preuves indirectes que les spermophiles pillent souvent les oeufs des tétras des armoises (Centrocercus urophasianus (Bonaparte, 1827)). L'ouverture maximale de la bouche mesurée sur des carcasses est de 26 mm et l'ouverture fonctionnelle, d'après les empreintes de dents sur des oeufs artificiels de glaise, est de 17 mm. Les spermophiles ont laissé des empreintes de dents sur 46 de 110 oeufs de glaise; cependant, lorsqu'on les a exposés à des oeufs de poules domestiques (Gallus gallus (L., 1758)) ou de faisans de Colchide (Phasianus colchicus L., 1758) qui s'approchent de la largeur maximale des oeufs de tétras des armoises, ou lorsqu'on les a mis en présence des oeufs beaucoup plus petits de cailles du Japon (Coturnix japonica Temminck et Schlegel, 1849) qui correspondent approximativement à l'ouverture maximale de la bouche, aucun spermophile (28 adultes et au moins 28 petits) ne s'est attaqué spontanément aux oeufs, même lors d'expositions répétées. Lorsqu'on les a exposés cette fois à des oeufs endommagés, 15 de 16 femelles adultes se sont nourries du contenu, bien que rarement lors de la première exposition. Après s'être nourris d'oeufs endommagés, 2 de 12 spermophiles ont ouvert des oeufs intacts, mais seulement des oeufs de cailles et généralement seulement si la coquille était rugueuse. Bien que les spermophiles de Richardson...

show abstract

Hunting Techniques and Tool Use by North American Badgers Preying on Richardson's Ground Squirrels

Cited by 43 publications

References 29 publications

Forelimb muscle architecture and myosin isoform composition in the groundhog (Marmota monax)

Forelimb muscle architecture and myosin isoform composition in the groundhog (Marmota monax)

If at first you don't succeed… Studies of ontogeny shed light on the cognitive demands of habitual tool use

Limits on egg predation by Richardson's ground squirrels

Contact Info

Product

Resources

About