Two populations of tree lizards (Urosaurus ornatus) that differ in morphological and social traits were used in a comparative study examining the relative influence of several variable characteristics on dominance relations. Adult males from the Aguirre Spring (AS) population exhibit monomorphic throat coloration, whereas Dofia Ana (DA) males are polymorphic. AS males are, in certain respects, more aggressive than DA males. Pairwise dominance contests were staged to assess relative contributions of size, social experience, and throat coloration in determining dominance outcome. Although the relative size of individuals has usually been regarded as a primary predictor of dominance, recent studies have shown that a disparity in color or experience can serve to override size differences between contestants. Data for size, recent dominance experience, and throat coloration were entered into logistic regression programs to generate models that were both predictive and explanatory. These models indicated effects of size, experience, and coloration in both populations. Throat coloration was a relatively stronger predictor of dominance outcome in males from the polymorphic (DA) population, whereas previous dominance experience was more important in AS males.
摘要以两个形态特征和社会特征不同的树蜥蜴(ornatus Urosaurus)为研究对象，研究了不同形态特征对优势关系的相对影响。来自Aguirre Spring (AS)种群的成年雄性表现为单态喉咙颜色，而Dofia Ana (DA)雄性则表现为多态喉咙颜色。在某些方面，AS男性比DA男性更具攻击性。两两优势竞争是为了评估大小、社会经验和喉咙颜色在决定优势结果方面的相对贡献。虽然个体的相对尺寸通常被认为是优势的主要预测因素，但最近的研究表明，肤色或经验的差异可以掩盖参赛者之间的尺寸差异。数据的大小，最近的优势经验，和喉咙的颜色被输入到逻辑回归程序，以产生既预测和解释的模型。这些模型表明了大小、经验和肤色对两个种群的影响。在多态(DA)群体中，喉咙颜色是一个相对较强的优势结果预测因子，而在AS男性中，先前的优势经验更为重要。
{"title":"MODELING DOMINANCE: THE INFLUENCE OF SIZE, COLORATION, AND EXPERIENCE ON DOMINANCE RELATIONS IN TREE LIZARDS (UROSAURUS ORNATUS)","authors":"G. C. Carpenter","doi":"10.2307/1466998","DOIUrl":"https://doi.org/10.2307/1466998","url":null,"abstract":"Two populations of tree lizards (Urosaurus ornatus) that differ in morphological and social traits were used in a comparative study examining the relative influence of several variable characteristics on dominance relations. Adult males from the Aguirre Spring (AS) population exhibit monomorphic throat coloration, whereas Dofia Ana (DA) males are polymorphic. AS males are, in certain respects, more aggressive than DA males. Pairwise dominance contests were staged to assess relative contributions of size, social experience, and throat coloration in determining dominance outcome. Although the relative size of individuals has usually been regarded as a primary predictor of dominance, recent studies have shown that a disparity in color or experience can serve to override size differences between contestants. Data for size, recent dominance experience, and throat coloration were entered into logistic regression programs to generate models that were both predictive and explanatory. These models indicated effects of size, experience, and coloration in both populations. Throat coloration was a relatively stronger predictor of dominance outcome in males from the polymorphic (DA) population, whereas previous dominance experience was more important in AS males.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1466998","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Donal M. Boyer, C. M. Garrett, J. B. Murphy, Hobart M. Smith, D. Chiszar, Dallas Zoo
Bushmasters (Lachesis muta) at Dallas Zoo demonstrated strike-induced chemo- sensory searching (SICS) and trail-following when feeding on relatively large prey (>25% of snake body mass). Smaller prey were usually held following predatory strikes. Facultative use of the strike-and-release pattern based on prey size has not previously been documented for any rodent- feeding viper. Experiment I documented the relationship between prey mass and post-strike holding or releasing. Experiment II showed that SICS occurred after large prey were released. Experiment III revealed that bushmasters followed chemical trails after releasing large prey, indicating that trailing behavior is a facultative component of predation in these snakes.
{"title":"IN THE FOOTSTEPS OF CHARLES C. CARPENTER: FACULTATIVE STRIKE-INDUCED CHEMOSENSORY SEARCHING AND TRAIL-FOLLOWING BEHAVIOR OF BUSHMASTERS (LACHESIS MUTA) AT DALLAS ZOO","authors":"Donal M. Boyer, C. M. Garrett, J. B. Murphy, Hobart M. Smith, D. Chiszar, Dallas Zoo","doi":"10.2307/1467003","DOIUrl":"https://doi.org/10.2307/1467003","url":null,"abstract":"Bushmasters (Lachesis muta) at Dallas Zoo demonstrated strike-induced chemo- sensory searching (SICS) and trail-following when feeding on relatively large prey (>25% of snake body mass). Smaller prey were usually held following predatory strikes. Facultative use of the strike-and-release pattern based on prey size has not previously been documented for any rodent- feeding viper. Experiment I documented the relationship between prey mass and post-strike holding or releasing. Experiment II showed that SICS occurred after large prey were released. Experiment III revealed that bushmasters followed chemical trails after releasing large prey, indicating that trailing behavior is a facultative component of predation in these snakes.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ecological Aspects of Foraging Mode for the Snakes Crotalus cerastes and Masticophis flagellum","authors":"S. Secor","doi":"10.2307/1467004","DOIUrl":"https://doi.org/10.2307/1467004","url":null,"abstract":"","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The behavior of 10 free-ranging male Anolis carolinensis was videotaped in a riparian habitat for 41 h during May-July of the breeding season; 8 of the original 10 males plus 1 substitute were videotaped for an additional 22 h during August-September of the post-breeding season. Comparisons of breeding versus non-breeding seasons showed dramatic shifts in the per- centage of time spent in the following behavioral modes: (1) "stationary," 51.1% versus 85.6% (with respective display rates of 46/h versus 2/h); (2) "travel," 26.7% versus 2.6% (with respective distance rates of 73 m/h versus 106 m/h and display rates of 209/h versus 78/h); (3) "creep," <1% versus 14.1% (with post-breeding distance rate of 17 m/h and display rate of 15/h); (4) "courtship," 4.2% versus 0% (occurring 1/40 min with a display rate of 233/h); (5) "copulation," 6.1% versus 0% (occurring 1/7 h, each averaging 15 min); (6) "male dispute," 9.2% versus 0% (occurring 1/h, with a display rate of 73/h); (7) "foraging," 1.0% versus 1.5% (occurring 1.2/h versus 3.6/h); and (8) "predator avoidance," "drinking," "defecation," and "shedding," total 1.5% versus 0.2%. Over all contexts, the respective breeding versus post-breeding season rates for distance moved and displaying were 26 m/h versus 8 m/h and 100 displays/h versus 6 displays/h. Breeding males were polygynous and defended exclusive, closely monitored home ranges (x = 174 m3) that overlapped an average of 2.8 resident females. Males used all available microhabitats and were considered perch generalists. Males spent two-thirds of their time between 0 and 2 m above the ground on perches 1-8 cm in diameter during the breeding season, but more often frequented higher and thinner perches in the post-breeding season, during which time much creeping and foraging occurred. Males exhibited a wide range of foraging behavior, reflecting a generalist's mode of prey capture. Feeding was initiated when stationary (sit-and-wait), traveling (eat-on-the-run), and creeping (active search); more feeding events were initiated from a stationary mode, but traveling (breeding season) and creeping (post-breeding season) produced more feeding attempts per unit of time. Males were bright green 75% (breeding season) and 87% (post-breeding season) of the time. Shifts between four categories of body colors (bright green to chocolate brown) averaged 4.7 (breeding season) and 1.0 changes/h (post-breeding season), with a bright green state maintained for significantly shorter durations during the breeding period than after the breeding period (x = 27.1 and 89.6 min, respectively). There was no evidence that change in body color was matching substrate color; however, green-to-brown shifts in body color were usually associated with the initiation of social interactions. Behaviors possibly associated with pheromone reception or deposition were infrequent (<8 times/h), occurring most often in the post-breeding season when no social behavior was observed. Based on
{"title":"BEHAVIORAL PROFILE OF FREE-RANGING MALE LIZARDS, ANOLIS CAROLINENSIS, ACROSS BREEDING AND POST-BREEDING SEASONS","authors":"T. A. Jenssen, N. Greenberg, Katheryn A. Hovde","doi":"10.2307/1466995","DOIUrl":"https://doi.org/10.2307/1466995","url":null,"abstract":"The behavior of 10 free-ranging male Anolis carolinensis was videotaped in a riparian habitat for 41 h during May-July of the breeding season; 8 of the original 10 males plus 1 substitute were videotaped for an additional 22 h during August-September of the post-breeding season. Comparisons of breeding versus non-breeding seasons showed dramatic shifts in the per- centage of time spent in the following behavioral modes: (1) \"stationary,\" 51.1% versus 85.6% (with respective display rates of 46/h versus 2/h); (2) \"travel,\" 26.7% versus 2.6% (with respective distance rates of 73 m/h versus 106 m/h and display rates of 209/h versus 78/h); (3) \"creep,\" <1% versus 14.1% (with post-breeding distance rate of 17 m/h and display rate of 15/h); (4) \"courtship,\" 4.2% versus 0% (occurring 1/40 min with a display rate of 233/h); (5) \"copulation,\" 6.1% versus 0% (occurring 1/7 h, each averaging 15 min); (6) \"male dispute,\" 9.2% versus 0% (occurring 1/h, with a display rate of 73/h); (7) \"foraging,\" 1.0% versus 1.5% (occurring 1.2/h versus 3.6/h); and (8) \"predator avoidance,\" \"drinking,\" \"defecation,\" and \"shedding,\" total 1.5% versus 0.2%. Over all contexts, the respective breeding versus post-breeding season rates for distance moved and displaying were 26 m/h versus 8 m/h and 100 displays/h versus 6 displays/h. Breeding males were polygynous and defended exclusive, closely monitored home ranges (x = 174 m3) that overlapped an average of 2.8 resident females. Males used all available microhabitats and were considered perch generalists. Males spent two-thirds of their time between 0 and 2 m above the ground on perches 1-8 cm in diameter during the breeding season, but more often frequented higher and thinner perches in the post-breeding season, during which time much creeping and foraging occurred. Males exhibited a wide range of foraging behavior, reflecting a generalist's mode of prey capture. Feeding was initiated when stationary (sit-and-wait), traveling (eat-on-the-run), and creeping (active search); more feeding events were initiated from a stationary mode, but traveling (breeding season) and creeping (post-breeding season) produced more feeding attempts per unit of time. Males were bright green 75% (breeding season) and 87% (post-breeding season) of the time. Shifts between four categories of body colors (bright green to chocolate brown) averaged 4.7 (breeding season) and 1.0 changes/h (post-breeding season), with a bright green state maintained for significantly shorter durations during the breeding period than after the breeding period (x = 27.1 and 89.6 min, respectively). There was no evidence that change in body color was matching substrate color; however, green-to-brown shifts in body color were usually associated with the initiation of social interactions. Behaviors possibly associated with pheromone reception or deposition were infrequent (<8 times/h), occurring most often in the post-breeding season when no social behavior was observed. Based on","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1466995","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Diet, Litter, and Sex Effects on Chemical Prey Preference, Growth, and Site Selection in Two Sympatric Species of Thamnophis","authors":"Lani P. Lyman-Henley, G. Burghardt","doi":"10.2307/1467002","DOIUrl":"https://doi.org/10.2307/1467002","url":null,"abstract":"","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Prerequisite to the evolution of social behavior is a context in which individuals can interact. Animal aggregations near preferred habitat features can provide such a context. Near times of gestation, oviposition, and parturition, habitat features that facilitate these processes may be specialized and of paramount importance to the fitness of gravid individuals. Additionally, spatial proximity to conspecifics may enhance individual fitness through antipredator, thermoregulatory, or osmoregulatory effects. Such effects could result in selection for attraction to conspecifics, as well as localized habitat features, and more complex mutualistic and manipulative social interactions. Furthermore, philopatry and the proximity of littermates, parents, and offspring at the time of parturition or hatching would enhance inclusive fitness effects of mutualistic interactions. Mutual attraction to preferred habitat features as exhibited by gravid squamates may provide a useful model of early stages in the evolution of more complex social systems. Literature concerning aggregation of gravid squamates, communal nesting and birth, and interactions among neonates and postparturient females is reviewed.
{"title":"AGGREGATION OF SQUAMATE REPTILES ASSOCIATED WITH GESTATION, OVIPOSITION, AND PARTURITION","authors":"B. Graves, D. Duvall","doi":"10.2307/1466999","DOIUrl":"https://doi.org/10.2307/1466999","url":null,"abstract":"Prerequisite to the evolution of social behavior is a context in which individuals can interact. Animal aggregations near preferred habitat features can provide such a context. Near times of gestation, oviposition, and parturition, habitat features that facilitate these processes may be specialized and of paramount importance to the fitness of gravid individuals. Additionally, spatial proximity to conspecifics may enhance individual fitness through antipredator, thermoregulatory, or osmoregulatory effects. Such effects could result in selection for attraction to conspecifics, as well as localized habitat features, and more complex mutualistic and manipulative social interactions. Furthermore, philopatry and the proximity of littermates, parents, and offspring at the time of parturition or hatching would enhance inclusive fitness effects of mutualistic interactions. Mutual attraction to preferred habitat features as exhibited by gravid squamates may provide a useful model of early stages in the evolution of more complex social systems. Literature concerning aggregation of gravid squamates, communal nesting and birth, and interactions among neonates and postparturient females is reviewed.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1466999","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In animals with asymptotic growth after maturity, a variety of factors can lead to inter- and intraspecific variation in sexual size dimorphism (SSD). Growth-based models tailored for a particular taxon provide a useful framework for analyzing questions about the proximate bases, adaptive significance, and evolution of SSD. This paper shows how growth-based models designed for Anolis lizards have been used to study the effects of male territorial and competitive behavior on SSD and adult size distributions. In a comparative study of different species of anoles, indices of SSD based on male and female asymptotic snout-vent length (SVL) have been used to confirm a prediction from territorial theory that SSD should be related to inter-female distance. Within populations of Anolis sagrei and Anolis limifrons, adult size distributions were sometimes skewed in favor of larger males than predicted by null growth-based models, as a result of the underrepresentation of small, young males in samples containing females of the same age. A relative shortage of newly mature males in adult size distributions is consistent with behavioral studies suggesting that young, small males may bear the brunt of aggression from larger territorial males. Hence, growth-based models can be used to suggest and test behavioral and other hypotheses about the factors affecting SSD.
{"title":"USING GROWTH-BASED MODELS TO STUDY BEHAVIORAL FACTORS AFFECTING SEXUAL SIZE DIMORPHISM","authors":"J. Stamps","doi":"10.2307/1466997","DOIUrl":"https://doi.org/10.2307/1466997","url":null,"abstract":"In animals with asymptotic growth after maturity, a variety of factors can lead to inter- and intraspecific variation in sexual size dimorphism (SSD). Growth-based models tailored for a particular taxon provide a useful framework for analyzing questions about the proximate bases, adaptive significance, and evolution of SSD. This paper shows how growth-based models designed for Anolis lizards have been used to study the effects of male territorial and competitive behavior on SSD and adult size distributions. In a comparative study of different species of anoles, indices of SSD based on male and female asymptotic snout-vent length (SVL) have been used to confirm a prediction from territorial theory that SSD should be related to inter-female distance. Within populations of Anolis sagrei and Anolis limifrons, adult size distributions were sometimes skewed in favor of larger males than predicted by null growth-based models, as a result of the underrepresentation of small, young males in samples containing females of the same age. A relative shortage of newly mature males in adult size distributions is consistent with behavioral studies suggesting that young, small males may bear the brunt of aggression from larger territorial males. Hence, growth-based models can be used to suggest and test behavioral and other hypotheses about the factors affecting SSD.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1466997","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68496151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. O’connor, J. S. Grumbles, R. George, L. C. Zimmerman, J. Spotila
Hematologic and plasma biochemical parameters were monitored in free-ranging desert tortoises, Gopherus agassizii, near Las Vegas, NV and on a population of captive tortoises maintained in 4 ha pens with natural physiography and vegetation and subjected to varying levels of water supplementation to mimic different levels of hydric stress. Significant increases in plasma electrolyte and urea nitrogen concentrations and white blood cell counts (compared to free-ranging and water-supplemented, captive animals) occurred in captive animals without water supplementation. Differences in electrolytes and BUN among treatments were consistent with altered water balance. Free-ranging animals received no supplemental water. Blood profiles from free-ranging animals, however, more closely resembled profiles from captive animals that received supplemental water than profiles from animals that did not receive supplemental water. Captivity, thus, altered blood profiles in a manner similar to that seen with decreased water availability. The electrolyte, urea nitrogen, and white blood cell differences among water supplementation treatments, while significant, were not sufficient to distinguish among animals from different treatments. No reliably predictive indicators of water stress-or other stresses-were found. Several biochemical assays suggested specific stresses (other than water stress) which some of the tortoises faced. We suggest that blood profiles might be more profitably used to search for specific hypothesized stressors in populations rather than as assays of unspecified generic stress on populations of tortoises.
{"title":"Potential Hematological and Biochemical Indicators of Stress in Free-Ranging Desert Tortoises and Captive Tortoises Exposed to a Hydric Stress Gradient","authors":"M. O’connor, J. S. Grumbles, R. George, L. C. Zimmerman, J. Spotila","doi":"10.2307/1467067","DOIUrl":"https://doi.org/10.2307/1467067","url":null,"abstract":"Hematologic and plasma biochemical parameters were monitored in free-ranging desert tortoises, Gopherus agassizii, near Las Vegas, NV and on a population of captive tortoises maintained in 4 ha pens with natural physiography and vegetation and subjected to varying levels of water supplementation to mimic different levels of hydric stress. Significant increases in plasma electrolyte and urea nitrogen concentrations and white blood cell counts (compared to free-ranging and water-supplemented, captive animals) occurred in captive animals without water supplementation. Differences in electrolytes and BUN among treatments were consistent with altered water balance. Free-ranging animals received no supplemental water. Blood profiles from free-ranging animals, however, more closely resembled profiles from captive animals that received supplemental water than profiles from animals that did not receive supplemental water. Captivity, thus, altered blood profiles in a manner similar to that seen with decreased water availability. The electrolyte, urea nitrogen, and white blood cell differences among water supplementation treatments, while significant, were not sufficient to distinguish among animals from different treatments. No reliably predictive indicators of water stress-or other stresses-were found. Several biochemical assays suggested specific stresses (other than water stress) which some of the tortoises faced. We suggest that blood profiles might be more profitably used to search for specific hypothesized stressors in populations rather than as assays of unspecified generic stress on populations of tortoises.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467067","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68498686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. O’connor, L. C. Zimmerman, D. Ruby, S. Bulova, J. Spotila
We constructed minimum convex polygon (MCP) home ranges for free-ranging desert tortoises from a natural population adjacent to the Desert Tortoise Conservation Center, near Las Vegas, NV. Home range area estimates were not significantly different from those estimated for other desert tortoises in the Mojave and Sonoran deserts. Male tortoises had significantly larger and more variable home ranges in a combined statistical analysis of this study with those of Burge (1977) and Barrett (1990). Bootstrap analysis of the MCP polygon areas suggested substantial autocorrelation of the tortoise sightings despite a mean interval between recaptures of 3.2 days, violating an assumption of nearly all home range estimation techniques and predisposing to underestimation of the true home range area. Extending the interval between recaptures would severely limit the number of points that could be obtained on an individual tortoise in a single activity season. We also created "by eye" minimum polygons to compare with MCP's for the same tortoises. This comparison suggests that MCP's for desert tortoises include, as substantial fractions of their total area (12-56%, mean = 35%), areas with no evidence that tortoises use them. Movements between resightings vary with the sex of the animal (male > female) and interval since previous sighting. The distance of movements was approximately exponentially distributed, with short movements more common than longer movements, predisposing home range estimates for desert tortoises to be autocorrelated. We urge the consideration of home range as an indicator of size of the areas traversed by a tortoise and the patterns of movement in different individuals, sexes, and/or populations with less emphasis on the biological interpretation of area as a resource or characteristic of the animal.
{"title":"Home Range Size and Movements by Desert Tortoises, Gopherus agassizii, in the Eastern Mojave Desert","authors":"M. O’connor, L. C. Zimmerman, D. Ruby, S. Bulova, J. Spotila","doi":"10.2307/1467070","DOIUrl":"https://doi.org/10.2307/1467070","url":null,"abstract":"We constructed minimum convex polygon (MCP) home ranges for free-ranging desert tortoises from a natural population adjacent to the Desert Tortoise Conservation Center, near Las Vegas, NV. Home range area estimates were not significantly different from those estimated for other desert tortoises in the Mojave and Sonoran deserts. Male tortoises had significantly larger and more variable home ranges in a combined statistical analysis of this study with those of Burge (1977) and Barrett (1990). Bootstrap analysis of the MCP polygon areas suggested substantial autocorrelation of the tortoise sightings despite a mean interval between recaptures of 3.2 days, violating an assumption of nearly all home range estimation techniques and predisposing to underestimation of the true home range area. Extending the interval between recaptures would severely limit the number of points that could be obtained on an individual tortoise in a single activity season. We also created \"by eye\" minimum polygons to compare with MCP's for the same tortoises. This comparison suggests that MCP's for desert tortoises include, as substantial fractions of their total area (12-56%, mean = 35%), areas with no evidence that tortoises use them. Movements between resightings vary with the sex of the animal (male > female) and interval since previous sighting. The distance of movements was approximately exponentially distributed, with short movements more common than longer movements, predisposing home range estimates for desert tortoises to be autocorrelated. We urge the consideration of home range as an indicator of size of the areas traversed by a tortoise and the patterns of movement in different individuals, sexes, and/or populations with less emphasis on the biological interpretation of area as a resource or characteristic of the animal.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467070","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68499061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Knowledge of burrow use and movement patterns, and how they are influenced by social interactions in desert tortoises, is critical to understanding habitat use in this threatened species. I examined sex differences and seasonal variation in burrow use by desert tortoises. Twentyeight free-ranging tortoises were fitted with radio transmitters and were regularly located from June-October 1992. Location and behavior of radio-tagged tortoises were recorded and occupied shelters were marked. Patterns of burrow use and co-occupancy differed between the sexes and corresponded to the reproductive cycle. Most observations were of tortoises inhabiting shelters singly. During the nesting season in June, female tortoises moved among shelters more than did males. During the mating season in August and September, males changed shelters more frequently than did females, and male-female co-occupancy was commonly observed. Consideration of burrow use patterns and associated social behavior may improve population density estimates, success of relocation management, and understanding of the epidemiology of upper respiratory tract disease.
{"title":"Patterns of Burrow Use by Desert Tortoises: Gender Differences and Seasonal Trends","authors":"S. Bulova","doi":"10.2307/1467077","DOIUrl":"https://doi.org/10.2307/1467077","url":null,"abstract":"Knowledge of burrow use and movement patterns, and how they are influenced by social interactions in desert tortoises, is critical to understanding habitat use in this threatened species. I examined sex differences and seasonal variation in burrow use by desert tortoises. Twentyeight free-ranging tortoises were fitted with radio transmitters and were regularly located from June-October 1992. Location and behavior of radio-tagged tortoises were recorded and occupied shelters were marked. Patterns of burrow use and co-occupancy differed between the sexes and corresponded to the reproductive cycle. Most observations were of tortoises inhabiting shelters singly. During the nesting season in June, female tortoises moved among shelters more than did males. During the mating season in August and September, males changed shelters more frequently than did females, and male-female co-occupancy was commonly observed. Consideration of burrow use patterns and associated social behavior may improve population density estimates, success of relocation management, and understanding of the epidemiology of upper respiratory tract disease.","PeriodicalId":56309,"journal":{"name":"Herpetological Monographs","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1467077","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68499093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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