Guanaco Research Articles

La fracturación de huesos largos durante el Holoceno medio en el Macizo del Deseado. Implicancias para el estudio del aprovechamiento de los guanacos.

En el presente trabajo evaluamos la variabilidad existente en la fracturación de los huesos largos de Lama guanicoe (guanaco) durante el Holoceno medio en la Meseta Central de Santa Cruz (Patagonia argentina). Para ello analizamos los conjuntos zooarqueológicos de la capa 2 de AEP-1 de Piedra Museo y del componente 2 de Cueva Maripe en La Primavera. Ambos contextos se emplazan en sectores diferentes de la cuenca de los zanjones Rojo y Blanco y en trabajos previos fueron definidos como espacios domésticos con diversas áreas de actividades (Cattáneo 2002; García Añino 2018; Lynch 2014; Marchionni 2013). Éste trabajo tiene como objetivo alcanzar una mejor comprensión de las estrategias de uso y aprovechamiento de los guanacos por parte de los cazadores-recolectores que habitaron esta región y aportar información de grano fino para el estudio de la variabilidad registrada en los sitios que solemos definir como domésticos o de actividades múltiples. El estudio se centra en el análisis de las distintas actividades que pudieron involucrar la fracturación intencional de los huesos. Los resultados muestran diferencias entre los conjuntos, siendo mayor la variabilidad de actividades que se expresan en los conjuntos de Cueva Maripe.

Hunting and skeletal element abundance of guanaco during the Holocene of Sierras of Córdoba, Argentina

The guanaco (Lama guanicoe) was the most important faunal resource exploited by past people from Sierras of Córdoba (Argentina). However, their relative taxonomic abundance decreased across the Holocene in relation to other small-taxa, which has been interpreted as an evidence of resource depression resulted from changes in the distribution of grassland and human hunting pressure. If the encounter rate with L. guanicoe decreased and hunters needed to travel greater distances to pursue a prey, it should be expected that the pattern in mean utility of body parts would parallel changes in the taxonomic composition of the assemblage. The expectation is that early archaic assemblages will have greater body-parts diversity than late prehispanic assemblages, reflecting a high encounter rate and a more complete deposition of entire carcasses. Conversely, late prehispanic people should respond to the greater cost of hunting by reducing transportation loads, carrying high-ranked body part of carcass to camps. The aim of this article is to test these predictions using a comprehensive analysis of the skeletal part representation from a suite of Holocene archaeological sites dated at 7400-to-360 years BP. The high and low-utility body part frequency observed during the initial and later phases reveals a more dynamic view of late prehispanic site formation process and raises new inquiries regarding whether different taphonomic histories of assemblages can have substantial influence on the skeletal element abundance.

Paleodietary trends in Late Holocene hunter-gatherers from southwestern La Pampa province, Argentina. First results from the Médano Petroquímica site through stable isotope analysis (δ13C and δ15N)

The aim of this work is to explore general trends and intra-site variability in human paleodiet from Médano Petroquímica, a burial site created by pre-Hispanic hunter-gatherers and located in the southwest of La Pampa province, Argentina. Measurements of carbon (13C/12C) and nitrogen (15N/14N) stable isotopes were performed on the human bone and tooth samples of 16 individuals from five of the burials identified in the site (EA, H4, H5, H6-1, and H7). The multivariate diet reconstruction model used indicates the consumption of land/terrestrial resources within a food web based mainly on C3 producers. The results suggest a relatively high trophic position for these individuals, which is consistent with a marked dependence on animal protein, particularly that of herbivores, such as Lama guanicoe, Rhea spp. (and/or its eggs), and omnivorous animals. A relatively greater dispersion observed in δ13Cap values in comparison with δ13Ccol and δ15N values is partially attributed here to greater intra-site variability in the non-protein portion of diet relative to the protein component.

A predictive model to diagnose pregnancy in guanacos (Lama guanicoe) using non-invasive methods

Pregnancy status is usually not included in ecological studies because it is difficult to evaluate. The use of non-invasive methods to determine pregnancy, without physically restraining individuals, would enable pregnancy to be included in population studies. In this study, we evaluated sex steroid hormones in plasma and fecal samples from pregnant and non-pregnant females to develop a pregnancy predictive model for guanacos (Lama guanicoe (Müller, 1776)). Samples were obtained during live-shearing management (i.e., capture, shear, and release) of guanacos. Enzyme immunoassays were used to evaluate progesterone (P4) and estradiol (E2) concentrations in plasma and pregnanediol glucuronides (PdG) and conjugated estrogens (EC) in feces. Mean hormonal and fecal metabolite concentrations were significantly higher in pregnant females than in non-pregnant females. A linear relationship was found between each hormone and its fecal metabolite. Finally, hormonal data were combined with an independent source of pregnancy diagnosis such as abdominal ballottement to develop a logistic regression model to diagnose pregnancy in non-handled individuals. The use of predictive models and non-invasive methods might be suitable to incorporate pregnancy information in large-scale population studies on guanaco and other free-ranging ungulates.

Diet selection and habitat use by the mountain vizcacha (Lagidium viscacia) in the Southern Andean Precordillera (Argentina)

Abstract Lagidium viscacia is considered as a fragile species with patchy distribution, a strict habitat specialist and an obligatory diet specialist. The Southern Andean Precordillera constitutes an interesting environment to analyze the species’ presence across the altitudinal gradient. Diet selection and habitat use were studied in the summit plateau, characterized by rigorous conditions and vegetation representative of the Southern Puna. Pellet groups were counted in transects perpendicular to rock formations, and diet and vegetation were seasonally analyzed using microhistological analysis and point-quadrat transects. Vizcachas were strictly associated with rock formations at middle and high altitudes, with higher occurrence on the mountain summit where grasslands surrounded the rock formations. Vizcachas avoided shrubs associated with rock formations and preferred grasses on sandy soils. Phenological changes slightly affected the selective diet that involves a considerable search effort and risky feeding activity. Puna grasslands constituted attractive feeding places where L. viscacia’s activity decreased with distance from rock shelters as expected for a central-place forager. Habitat partitioning allows coexistence with Ctenomys mendocinus, despite the high dietary overlap between these central-place species. The high mobility and broad diet of Lama guanicoe reduce the competition risk. Lepus europaeus preferred shrubs and forbs, determining a discrete dietary overlap with vizcachas.

Lama guanicoe bone collagen stable isotope (C and N) indicate climatic and ecological variation during Holocene in Northwest Patagonia

This paper explores how significant are the ecological and climatic variables to influence the stable isotopes of guanacos. Lama guanicoe bone collagen carbon and nitrogen stable isotope ratios are assumed as a macro regional average value in west Argentina, mostly as a baseline to model archaeological human diet. If stable isotopes on mammals reflex ecology and climate, we need to know how those variables influence mammals bone stable isotope ratio. This paper analyses the 13C/12C and 15 N/14N ratio on bone collagen on 122 guanacos from Northwest Patagonia during the Holocene. The results confirm significant variation in both isotopes between Monte and Andean-Patagonian specimens. Guanacos from Monte shows higher δ13C and δ15N than those from Andean-Patagonian. Temporal trends indicate variation through Holocene but this variation is not spatially homogeneous. In this paper we suggest that Medieval Climatic Anomaly had stronger effect in Monte desert than in Patagonia desert, generating driest and/or hottest conditions between 1250 and 600 years BP. Those variations need to be considered to reconstruct human diet at least during the second part of the Holocene.

Use and forget: Contribution to the discussion about the bone tools called “machacadores” (pounders), Patagonia, South America

• Features identified on epiphysis of guanaco long bones from Patagonian are discussed. • Experimental tools were made in Lama guanicoe long bones. • The replicas were used to crush and hammer soft and hard materials. • Our work sustains that “ machacadores ” were opportunistic artifacts. • “ Machacadores ” are not a fracture technique to provoke a transversal fracture.

Análisis de las fracturas de huesos largos de guanaco del sitio El Rincón. Península de Puerto San Julián, Santa Cruz.

En este trabajo se estudia un conjunto de especímenes óseos hallados en el sitio El Rincón, ubicado en un médano en la península de Puerto San Julián, Provincia de Santa Cruz. En los sectores de mayor concentración de materiales, al noreste del sitio, se delimitaron y analizaron tres locus de restos óseos. Estos fueron segmentados en cuadrículas con el propósito de efectuar el relevamiento sistemático in situ de las características taxonómicas y anatómicas. La muestra analizada se compone por huesos largos, en su mayoría de Lama guanicoe, que presentan evidencias de fractura. A su vez desde una perspectiva morfológica y funcional se evalúa el origen de estas fracturas. Además se identifican los agentes y procesos tafonomicos que pudieron alterar el material. Los restos óseos del conjunto se habrían originado en actividades de procesamiento y consumo de presas, evidenciadas en las prácticas de fractura transversal/marcado perimetral, en su empleo como machacadores y en otras marcas antrópicas. A su vez estos huesos podrían haber sufrido sucesivos procesos de enterramiento y desenterramiento durante los cuales actuaron agentes antrópicos y naturales, como el viento y el agua provocando su alteración y meteorización.

Geometric morphometrics of large South American camelids and their potential for the taxonomical identification in archaeological sites of the northern Argentina

ABSTRACT The large South American camelids, the llama (Lama glama) and the guanaco (Lama guanicoe), present a low level of morphological variation in the skeleton and a significant overlap in their body size at population scale. Therefore, if we consider the inter-specific and intra-specific variability, it is difficult to distinguish between wild (guanaco) and domestic (llama) species, based only on osteometric analysis of remains from archaeological sites. Techniques based on 2D geometric morphometric were applied in order to test their power for the taxonomic identification of these two camelids species through shape study of three anatomic elements: the first anterior and posterior phalanges, and the glenoid fossa of scapula. A total of 59 skeletal elements of 29 modern individuals and 14 archaeological specimens were analysed. The morphogeometric evaluation differentiated the skeletal element shapes of modern camelids groups. The archaeological samples revealed the presence of llama and guanaco in the archaeological record of the Argentinean Northwest at 1900–1300 BP. Nevertheless, domestic species were dominant in Antumpa site, whereas wild species were better represented in Condor II. This exploratory study provided an advance in the efforts of taxonomic identification of bone remains from the shape analysis performed on modern individuals of living species.

Evolutionary history of herbivory in the Patagonian steppe: The role of climate, ancient megafauna, and guanaco

Herbivory is an important ecological process than has influenced the evolution of grassland-savannah systems. The evolutionary history of herbivory largely determines how resilient plant communities are to herbivory, with communities evolving with a long history generally possessing plant adaptations that make them able to cope with such disturbance. Thus, the evolutionary history of herbivory can serve as an indicator of a system’s resilience to modern grazing. Determining this history, however, is problematic because quantitative measures of herbivory and knowledge of plant origin are needed over appropriate evolutionary time frames. Paleoecology offers a useful framework for assessing this evolutionary history of plant-herbivore interactions. The Patagonian steppe is a phytogeographic province of South America whose evolutionary history of herbivory has been debated. Past discussions have focused completely on the abundance of its sole large ungulate herbivore—the guanaco (Lama guanicoe Müller 1776)—since European colonization of the continent. Here we use a paleoecological approach to reconstruct the evolutionary history of herbivory and plant evolution in the Patagonian steppe over a much broader, geologic time frame (Cenozoic) to shed light on the matter. We examine the role of past climate, ancient megafauna, and guanaco in shaping the vegetation and briefly discuss how present land use may be misaligned with the steppe’s evolutionary history of herbivory.

Animal food during the Late Prehispanic Period at Sierras of Córdoba, Argentina. A zooarchaeological view from Boyo Paso 2

How prehispanic foragers adjusted their foraging activities to plant cultivation is a question that drives much of the modern archaeological research. As a result, the spread of food-producing economies during the Late Prehispanic Period (c. 1500-360 BP) from Sierras of Cordoba, Argentina, has been recently defined as a dynamic sociocultural process, where a mixed foraging and cultivation economy was accompanied by a flexible land-use strategy. However, the economic organization has only been superficially assessed. Thus, the aim of this article is to present the study of faunal remains recovered during the excavation of the open-air site Boyo Paso 2 in order to provide primary data on the properties of the animal food remains left by late prehispanic people and the characteristics of site occupation. Faunal remains suggest a complex sequence of reoccupations where bones were deposited, accidentally reburned and fragmented by trampling. The diversity of exploited prey also sheds light on the fact that a broad hunting spectrum continued playing a key role in the daily subsistence. Nevertheless, cultigens were a fluctuating component in a diverse foraging economy in which wild resources as guanaco (Lama guanicoe Muller, 1776), small-vertebrates and Rheidae eggs continued to be extensively used. The study of Boyo Paso 2 faunal assemblage is relevant because it helps to improve the current understanding of the economic importance of foraging wild resources and would constitute a model to interpret other archaeological cases during the Neolithic or Formative transition, where the boundaries between farming and foraging were fluid, but remained relatively invisible according to the existing terminology.

Modern guanaco (Lama guanicoe, Camelidae) bezoars: An approach towards identification in the fossil record

ObjectiveProvide a frame of reference for the recognition and interpretation of bezoars recovered from archeological and paleontological sites. Materials49 bezoars from extant guanaco (Lama guanicoe) were analyzed and compared with five objects previously identified as bezoars, recovered from Holocene archeological sites of the Argentine Pampas. MethodsSize, shape, weight, external and internal features, and mineralogical composition were evaluated in both modern and archeological bezoars using nondestructive and destructive methods. ResultsModern and archeological bezoars are formed by calcium phosphate and display great morphological variability linked to ante-mortem processes, taphonomic alterations, and anthropic activity. ConclusionsMorphometry, along with external and internal features and mineral composition, are useful tools for the identification and interpretation of bezoars in the fossil record. SignificanceThis study offers new information on the etiology, mechanisms of formation, and means of interpreting the presence of bezoars, a common pathology in South American camelids, in the fossil record. LimitationsThe features of fossil bezoars do not provide accurate identification of the animal that produced them. Suggestions for Further ResearchFurther analyses on modern bezoars belonging to other species of mammals are needed in order to enhance the interpretation of bezoars in the fossil record.

Effect of population density on diet composition and dietary niche breadth of guanaco (Lama guanicoe, Müller 1776) in northeastern Patagonian steppes

The optimal foraging theory postulates that as animal population density increases, the progressive decline in preferred forage availability results in changes in diet composition and widening of dietary niche breadth. For sedentary guanaco populations, some authors proposed a mechanism of population density limitation below the environmental carrying capacity, mediated through territoriality. Under the optimal foraging theory, increased density would lead to changes in guanaco diet selectivity and composition. Conversely, under the self-regulation hypothesis, guanacos would not affect preferred forage availability and no differences in guanaco diet would be expected. We tested these contrasting hypotheses by assessing both the differences in the proportion of grasses and shrubs present in guanaco diet and dietary niche breadth at three contrasting densities in northeastern Patagonian steppes. We did not find guanaco density effects on preferred forage availability, grass-shrub proportions in the diet and diet selectivity. Guanacos showed a mixed diet composed by plant species of both high and low nutritional quality independently of population density. The lack of changes in diet composition suggests that guanacos did not perceive a restriction in forage availability in terms of either biomass or nutritional content, regardless the observed increase in population density.

Are there different vigilance strategies between types of social units in Lama guanicoe?

Group vigilance is a cooperative behaviour in social species that reduces individual risk of predation. Lama guanicoe is a social species of camelid performing cooperative vigilance, but little is known about the vigilance behaviour of different social units. We analysed the vigilance behaviour in different types of social units of L. guanicoe, to better understand the complexity of this behaviour. The best supported models for both the frequency of vigilance and the proportion of time vigilant included the type and size of social units as the most important predictors that affect the vigilance behaviour. Solitary males devoted proportionally more time in vigilance behaviour than family, mixed or bachelor groups, whereas females in female groups spent more time vigilant than guanacos in mixed groups. Frequency of vigilance was higher in family individuals and solitary males than in bachelor or mixed groups. It is likely that that in family and females groups, the presence of offspring would increase the vigilance behaviour to detect possible predators. Topography and habitat characteristics that determine the predation risk, affected vigilance behaviour of mixed groups and solitary males. Our results suggest that vigilance behaviour should not be generalized for this species, since there are differences between the types of social units, probably related to intrinsic characteristics of each one and the perception of risk.

How Roads Affect the Spatial Use of the Guanaco in a South American Protected Area: Human Connectivity vs Animal Welfare

Roads can affect animals as well as their habits at different levels. Avoidance behavior is a common response of animals to this type of perturbation, preventing access to areas rich in resources. The effects of roads on ungulates have not been studied in South America extensively, especially in arid environments. We have studied the space use by ungulates in relation to roads, using a dung heap count and camera traps. The aim was to evaluate whether paved road and unpaved road may have an effect on the spatial use of a low density population of guanacos (Lama guanicoe) in Ischigualasto Provincial Park, Argentina. We observed an increase in dung heap abundance in unpaved road as respect to paved road, this difference was larger for both. Besides, we recorded less individuals in paved road zones than in unpaved road zones. This showed that roads, especially paved roads, negatively affect the space used by guanacos. Our results are relevant to the management and conservation of animal populations in protected areas since spatial segregation due to the presence of roads may lead to the isolation of individuals. It is important to pay attention and further assess the effects that roads can have in the native fauna.

Demography of avian scavengers after Pleistocene megafaunal extinction

The late Quaternary megafauna extinctions reshaped species assemblages, yet we know little about how extant obligate scavengers responded to this abrupt ecological change. To explore whether obligate scavengers persisted by depending on contemporary community linkages or via foraging flexibility, we tested the importance of the trophic interaction between pumas (Puma concolor) and native camelids (Vicugna vicugna and Lama guanicoe) for the persistence of Andean condors (Vultur gryphus) in southern South America, and compared the demographic history of three vultures in different continents. We sequenced and compiled mtDNA to reconstruct past population dynamics. Our results suggest that Andean condors increased in population size >10 KYA, whereas vicuñas and pumas showed stable populations and guanacos a recent (<10 KYA) demographic expansion, suggesting independent trajectories between species. Further, vultures showed positive demographic trends: white-backed vultures (Gyps africanus) increased in population size, matching attenuated community changes in Africa, and California condors (Gymnogyps californianus) exhibited a steep demographic expansion ~20 KYA largely concurrent with North American megafaunal extinctions. Our results suggest that dietary plasticity of extant vulture lineages allowed them to thrive despite historical environmental changes. This dietary flexibility, however, is now detrimental as it enhances risk to toxicological compounds harbored by modern carrion resources.

The relationship between coping styles and responses to handling in captive guanacos (Lama guanicoe)

The objective of the present study was to evaluate the coping style response to handling of guanacos (Lama guanicoe) in captivity. This study contributes to a better understanding of the handling effect in captivity of the largest wild camelid of South America. Individual coping style response to handling was studied in 17 adult captive-bred guanacos. Handling was performed every 2 h for 24 h and serum cortisol concentration and behavioral responses were measured during the entire cycle of handling (12 times). Principal component analysis results showed three main factors: the first associated with reactive behavior (more immobility and escaping, less spitting) and the second and third associated with proactive behavior (more territorial control behaviors and less jumping). Nine animals were classified as reactive and eight as proactive, based on the highest component score attained. Mean cortisol concentration was 368.45 nmol/L in the reactive group and 155.96 nmol/L in the proactive group (p < 0.01). The lower levels of cortisol in the proactive group could indicate a higher ability to cope with adverse factors than the reactive group. An assessment of coping styles could improve the establishment of different management strategies oriented to increase animal welfare for diverse species of small ruminants in captivity.

Linking diet quality and energy demand in free‐living guanacos: an eco‐physiological innovative approach

AbstractIn adaptive terms, animals are subject to challenges imposed by their environment. To address physiological patterns in wild mammals, the non‐invasive study of glucocorticoid hormones has become the main approach through two well‐defined conceptual frameworks: one is related to stress responses, whereas another refers to the glucocorticoids as physiological mediators of the allostatic load, necessary for the maintenance of homeostasis. A key factor to analyse the physiology of wild animals is to understand the relationship between energetic demands and nutritional attributes. The objective of this study was to assess the influence of diet quality on physiological mediators of energy mobilization in two populations of wild guanacos (Lama guanicoe) from Northern Patagonia. In order to evaluate energy mobilization and its relationship with diet quality, we quantified nitrogen content and cortisol metabolite concentrations in fresh faeces. Samples were collected in two contrasting seasons (summer and winter, representing the breeding and non‐breeding seasons respectively). Summer was identified as the period of highest diet quality and energy mobilization, in both sexes and populations. We found quadratic relationships between cortisol levels and nitrogen percentage, which we hypothesize corresponds to two different factors: one of an energetic‐nutritional nature (during winter, the non‐reproductive season), and the other of an energetic‐reproductive nature (during summer, the reproductive season). Our evidence suggests variation in the administration of energy resources in guanacos in response to internal and external stimuli, giving rise to a novel Biphasic Model of energy demand. Our results reinforce the knowledge of the adaptive eco‐physiological attributes of guanaco, and we describe a new conceptual model which explains the energy management patterns for this species and possibly for other ungulates, within the breeding and non‐breeding seasons.

Patterns of Resource Use and Isotopic Niche Overlap Among Guanaco (Lama guanicoe), Pampas Deer (Ozotoceros bezoarticus) and Marsh Deer (Blastocerus dichotomus) in the Pampas. Ecological, Paleoenvironmental and Archaeological Implications

ABSTRACT In this paper, we analyze the isotopic niche and resource use of the guanaco (Lama guanicoe), pampas deer (Ozotoceros bezoarticus) and marsh deer (Blastocerus dichotomus) on the temperate plain of the northern Pampa region in the southeast of South America. The measured stable isotope compositions in bone tissue are δ13C, δ15N and δ18O. All the analyzed samples were recovered from different archaeological sites from the late Holocene. According to the results, the guanaco was strictly confined to the Pampa plain environment, developing a broad niche based on C3 plants and a variable contribution of C4 grasses within a grazing trend. The pampas deer preferentially used the Pampa plain, but also the prairies on the borders of the wetland, showing eurioic characteristics and a narrower niche based on C3 plants. In turn, the marsh deer was strictly confined to wetland environments, developing a C3 diet–base, within a narrow isotopic niche and stenoic characteristics. The three mammals showed a wide range of intraspecific variability, which was a key factor in their adaptability to spatial and temporal changes in the vegetation coverage. In fact, the temporal trends of their isotopic values were concurrent with the major climatic variations of the Holocene. Differences in the correlations between the values of both carbon sources in both deer species compared with the guanaco suggest a distinct chemical composition of their diet and/or differences in the allocation of nutrients. The isotopic values of nitrogen and spacing of the carbon sources in guanaco (pseudoruminant) and both deer species (ruminants) show no significant differences between them, thus establishing the values for local large herbivores. Significant correlations between δ13C and δ15N were found in the guanaco and marsh deer. The regional and extra–regional variability in the guanaco's δ13Ccollagen and δ15N probably reflect the clinal variations in the vegetation coverage and the amount of rainfall. The collagen isotope values in the guanaco throughout the entire Holocene show that the humid Pampa would have shifted between being a more recurrent mesic and temperate plain with minor phases of dry–mesic conditions like during the Little Ice Age, and a humid and warm one at the peaks of the Holocene Thermal Maximum and the Medieval Climatic Anomaly. The guanaco and the pampas deer adapted to all the climatic changes that happened on the humid Pampa until the biological invasions of large European mammals changed the herbivores’ guild composition of this vast plain, pushing them into peripheral habitats due to competition. The within–species variability in isotopic signals through time and space make it necessary to carry out adequate sampling before reconstructing the diets of local past populations.

Endoparásitos en guanaco (Lama guanicoe). Revisión de situación en Argentina y registros de la provincia de San Juan

Este estudio recopila los registros de especies endoparasitarias en guanacos (Lama guanicoe) de Argentina. Se hizo una revisión bibliográfica de los trabajos científicos publicados entre 1967 y 2017. Además, se incorporaron nuevos registros inéditos de localidades dentro de la provincia de San Juan. La fauna de endoparásitos estuvo representada por los phylum Nematoda, Platyhelminthes y Aplicomplexa, con un total de 65 registros totales, mencionando 26 especies y otras 14 que sólo fueron identificadas a nivel de género. Los nematodos fueron los más numerosos, seguido por el Aplicomplexa y en menor medida el pylum Platyhelminthes. Este trabajo menciona por primera vez la presencia de nematodos como Nematodirus sp, Trichuris sp, las coccidias E. macusaniensis, E. ivitaensis y Eimeria sp en guanacos silvestres de la provincia de San Juan. Hubo pocos registros en ambientes con poblaciones pequeñas de guanacos de la ecorregión Puna.