Energy metabolism and body water turnover rates of two species of free-living kangaroo rats, Dipodomys merriami and Dipodomys microps

Mullen, Robert K.

doi:10.1016/0300-9629(71)90302-1

Cited by 86 publications

(16 citation statements)

References 13 publications

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“…However, D. merriami has the greater ability to concentrate salts in urine (Kenagy, 1973), presumably because D. microps ingests more water in its leafy diet. Not surprisingly, body water turnover is more rapid in D. microps (Mullen, 1971 (Sherbrooke, 1976). We offered jojoba seeds to D. merriami captured both in areas where the plant occurs and in shadscale scrub several hundred kilometers away, as well as to naive laboratory-reared animals descended from both geographical populations.…”

Section: Discussionmentioning

confidence: 99%

Food aversion learning in kangaroo rats: A specialist-generalist comparison

Daly

Rauschenberger

Behrends

1982

Animal Learning & Behavior

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Two species of kangaroo rat (Dipodomys), varying in their degree of dietary specialization, were compared in a series of food aversion learning experiments to test the hypothesis that rapid aversion learning is an adaptation of relatively generalist feeders. The more generalist species indeed learned better or more rapidly in certain experiments, but species differences were at least partly a function of the specific test foods. Interpretation of results is complicated by differences between the two species in their initial reactions to particular foods, in the relative efficacy of different foods in supporting learned aversions, and perhaps even in their physiological responses to illness-inducing and control procedures.In the past decade, many psychologists have embraced the notion that animal learning must be viewed comparatively, with attention being given to the ecological specializations and predispositions of subject species. But despite the popularity of such ideas (e.g., Hinde & Stevenson-Hinde, 1973;Seligman & Hager, 1973), there has been surprisingly little explicitly comparative investigation: Few have asked if related animal species that differ in their ecological adaptations respond differently to similar contingencies, and, if so, exactly how.Food aversion learning has been a favorite paradigm of critics of general accounts of learning because of the striking phenomena of long effective delays of reinforcement (Garcia, Ervin, & and cue specificity . The animal that has been most studied is the laboratory rat, a species that associates taste cues and subsequent gastric distress with ease. Rozin (1976) in particular has suggested that the rat's capacity for adaptive modification of feeding behavior is the species-specific adaptation of a dietary "generalist," and that "specialists" might be less talented in this sphere."Specialist-generalist" is clearly not a dichotomy. It may be treated as a dimension along which species may be ranked according to some index of diversity of foodstuffs consumed. A different definition of specialization focuses upon morphological and behavioral adaptations to particular foodstuffs, but we should expect animals that are specialists by the latter criterion to be specialists by the former as well. A clear case of a dietary specialization by either criterion is provided by the chisel-toothed kangaroo rat, Dipodomys microps, in the Owens Valley of California. Most Dipodomys species are predominantly granivorous, consuming seeds of a variety of plant species, but greens are a substantial dietary element in certain seasons. Owens Valley D. microps, by contrast, feeds almost exclusively upon the salty, succulent leaves of chenopod plants, mainly shadscale (Atrip/ex conjertifo/ia), a diet for which it exhibits behavioral and morphological specializations (Kenagy, 1972(Kenagy, , 1973. Cheek pouch and stomach content analyses confirm that D. microps takes a less diverse diet than other Dipodomys, particularly D. merriami, a sympatric species of more typical food habits (e.g., ...

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Section: Discussionmentioning

confidence: 99%

Food aversion learning in kangaroo rats: A specialist-generalist comparison

Daly

Rauschenberger

Behrends

1982

Animal Learning & Behavior

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“…However, hibernation usually terminated in death after 7 days due to a loss of 25 per cent of body weight and body temperature dropping below l40C. Mullen (1971) found that D. merriami and D. microps apparently went into a diurnal torpor in nature. Kenagy (1973) found D. merriami and D. microps active at temperatures down to -19°C with no cessation of movements in powdery snow.…”

Section: Seasonal Activitymentioning

confidence: 96%

Seasonal Activity Patterns of Rodents in a Sagebrush Community

O’Farrell

1974

Journal of Mammalogy

111

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Twelve species of nocturnal rodents were studied on a 2.7-hectare plot of sagebrush desert in west-central Nevada. Six species, Dipodomys merriami, D. ordii, D. panamintinus, D. microps, Onychomys torridus, and Peromyscus maniculatus, were active throughout the year. Four species, Perognathus longimembris, P. formosus, Microdipodops megacephalus, and Reithrodontomys megalotis, hibernated and were active only in spring, summer, and autumn. Onychomys leucogaster and Neotoma lepida were trapped intermittently throughout the year but were not permanent residents on the area. Differences in time of daily activity were found between potential competitors demonstrating a degree of temporal isolation. Time after sunset and amount of moonlight were the two most important factors correlated to rodent activity. Ambient temperature, wind, cloud cover, precipitation, and water vapor pressure had little effect on activity except when extreme conditions prevailed.The desert supports a wide variety of rodents and provides a natural laboratory to study the effect of rigorous environmental conditions on small mammal species. Numerous studies have been made on rodents of the low desert of the southwestern United States, but the sagebrush community of the Great Basin has been neglected. Hall (1946) provided the most complete information on species of the Upper Sonoran Life-zone. Since then mostly fragmentary information on the biology of these rodents has become available. However, Kenagy (1973) presented excellent comparative information for several desert species.A continuing problem in mammalian ecology concerns the methods by which sympatric species coexist. In the sagebrush desert of west-central Nevada at least 12 species of nocturnal, surface-active rodents coexist sympatrically. With such a large number of species, it was apparent that the sage desert provided a unique opportunity to study various mechanisms of coexistence.The purpose of the present study was to examine daily and seasonal activity patterns of nocturnal rodents. The major approach was measurement of frequency of captures throughout the night. Various environmental parameters were monitored concurrently as possible correlates to activity. The focal point of the study was to describe the trends in activity of individual species and to relate the patterns exhibited by potentially competing species. Likewise, environmental factors were examined to establish a predictive base for species behavior in relation to general environmental conditions. MATERIALS AND METHODSThe study area was located at the northern end of Warm Springs Valley, about 40 kilometers (km) north of Sparks, Highway 33, Washoe Co., Nevada (1363 meters, m, elevation). The selected site was approximately 200 m east of the highway. A 12 by 12-station grid, 2.7 hectares, was staked out at 15 m intervals. Vegetation primarily consisted of 809

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“…A promising technique for field studies is the measurement of C02 production using doubly labeled H20 (see Lifson and McClintock [1966], Mullen [1973], and Nagy [1975] for discussions of theory and practical application). Minimal or maximal rates may be obtained and the influence of single factors upon metabolic performance can be evaluated.…”

Section: Introductionmentioning

confidence: 99%

Energy Expenditure in Free‐Ranging Lizards

Bennett¹,

Nagy²

1977

Ecology

121

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Metabolic rates of the western fence lizard Sceloporus occident a lis (Sauria: lguanidae) were measured in the laboratory by gas exchange, and in the field with doubly labeled H20. Field metabolic rates of adults during the spring reproductive season (0.22 ml C02 g-1 h-1 or 141.4J g-1 day-1 ) were not different from those during the fall nonreproductive season (0.20 ml C02 g-1 h-1 or 127.2J g-1 day-1 ). Field and laboratory metabolic rates of o o were not different from those of 2 2 in spring or fall. Average daily field metabolic rates were 2.0 to 2.5 x resting laboratory rates measured on a simulated normal thermal cycle; estimated rates during the field activity period were 2.5 to 3.1 X resting levels measured at 3SOC. Only 11 to 17% of total daily energy expenditure was used while lizards were inactive in their burrows. Daily field metabolism of this lizard is only 3 to 4% that of a bird or mammal of equal size.

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Energy metabolism and body water turnover rates of two species of free-living kangaroo rats, Dipodomys merriami and Dipodomys microps

Cited by 86 publications

References 13 publications

Food aversion learning in kangaroo rats: A specialist-generalist comparison

Food aversion learning in kangaroo rats: A specialist-generalist comparison

Seasonal Activity Patterns of Rodents in a Sagebrush Community

Energy Expenditure in Free‐Ranging Lizards

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