Decades of analyses indicate that dog (Canis lupus familiaris L) and human (Homo sapiens L) archaeological bone collagen S13C and S15N isotopic ratios are often similar, which presumably indicates similar diets. This makes sense given that most dogs occupy human-created environments and that much if not all of their food is sourced from human behavior. This has led some to suggest that dog isotopic ratios can be used as proxies for human ratios in archaeological contexts where human bone is not available for analysis. A meta-analysis of 64 cases with dog and human bone collagen S13C and S15N isotopic ratios indicates dog isotope ratios are not good direct proxies for humans when considering human diets. However, dog ratios can be used cautiously when considering specific food sources, such as C4-pathway grain crops, recognizing the possibility of false negatives in the absence of other subsistence evidence.

Ice-dammed lakes were common along the southern margin of the Laurentide Ice Sheet during deglaciation. In the Schoharie Valley of the northern Catskill Mountains, New York, a 171 km2 lake known as glacial Lake Grand Gorge formed in an interlobate area. Previous researchers suggested that deltas developed into this glacial lake from meltwater supplied by the adjacent Hudson Lobe during deglaciation. This study investigates stratigraphy and sedimentology of Pleistocene deltas and lake deposits to determine the source of meltwater and sediment. Detailed examination of stratigraphy from quarries, stream exposures, and new exploration borings was combined with radiocarbon and OSL geochronology to establish event stratigraphy. Sedimentologic and geomorphic data from deltas in the Manor Kill and Platter Kill Valleys demonstrates that braided outwash was supplied directly from the Westerlo Sublobe that crossed the northeastern escarpment of the Catskill Mountains. New geochronologic data indicates that the lake was established by 28 ka and likely persisted to at least 22 ka. Insects and twigs recovered from lake sediments complement the OSL data and indicate: (1) that the lake was present significantly earlier than previous deglacial models predict, and (2) that it existed in an ice-free area of the northern Catskill Mountains during the last glacial maximum of the MIS 2 glaciation.

The stable carbon isotope composition (delta C-13) of mammalian hard tissues offers a powerful tool for understanding the ecology of modern and fossil species. Over the past 40 years, the offset between delta C-13 values measured in structural carbonate and collagen (Delta(ca-co)) has been used as an indicator of trophic category. However, several recent studies have demonstrated substantial variation in the Delta(ca-co) values of herbivores, raising calls for caution in the use of static Delta(ca-co) values to interpret trophic relationships. To better clarify mechanisms driving variation in herbivore Delta(ca-co), we examined the relationship between delta C-13(carbonate) and delta C-13(collagen) in modern and Late Pleistocene ungulates from C-3-dominant ecosystems in the Americas and Eurasia. Factors investigated included diet, digestive physiology, and tissue type. Our results showed considerable variation in herbivore Delta(ca-co), underscoring the need for caution when applying static values to reconstruct trophic position. We found a consistent diet-driven pattern in Delta(ca-co) values (grazer > mixed feeder > browser). Identifying this pattern in modern and ancient species adds to growing evidence for the generalizability of the relationship between herbivore diet and Delta(ca-co). In contrast, the fossil data set showed evidence counter to predictions based on physiology: non-ruminants displayed higher Delta(ca-co) values and a greater rate of increase in delta C-13(carbonate) relative to delta C-13(collagen) than ruminants. Finally, tissue type substantially influenced Delta(ca-co), with values derived from teeth generally higher and more variable than from bone. This work highlights the potential for herbivore Delta(ca-co) to serve as a refined indicator of dietary ecology in modern and ancient ecosystems.

Evaluating the factors that promote coexistence between ecologically similar species is crucial to understanding the evolution and assembly of herbivore communities. The Jarman–Bell principle presents a trade-off between diet quality and quantity as an axis for dietary niche segregation and has been suggested as a mechanism facilitating species coexistence. This idea holds that larger-bodied herbivores consume greater amounts of relatively low-quality plant resources, while smaller-bodied herbivores typically feed selectively on higher-quality resources. Most studies investigating the Jarman–Bell principle have examined free-living ungulates in African savannas. The diverse ungulate community in Yellowstone National Park, USA offers an opportunity to investigate the applicability of this principle in a temperate North American ecosystem. In this study we use fecal nitrogen (FN) and stable carbon isotope values (δ13C) to examine the relationship between body size and seasonal patterns of dietary niche segregation among five species of wild ungulates. Specifically, we test the predictions that: (1) diet quality decreases with increasing body mass, (2) interspecific differences in diet are greatest between the largest- and smallest-bodied species, and (3) smaller-bodied species have narrower dietary breadth than larger-bodied species. Diet quality, as indicated by digestibility, declined significantly with body mass, consistent with the empirical pattern predicted by the Jarman–Bell hypothesis. Significant interspecific differences in diet quality generally aligned with variation in body mass. When resources were limited during the winter, the relationship between body mass and diet quality was more pronounced, suggesting increased dietary niche segregation during the lean season. The results showed little evidence indicating that dietary breadth scaled allometrically with body mass, as the two species most similar in body mass displayed the greatest and least range of seasonal variation in both FN and δ13C. This study adds to the weight and breadth of evidence that diet quality is negatively correlated with body size in wild ungulate assemblages. Our findings underscore the importance of body size as a factor facilitating dietary niche segregation and promoting coexistence among ecologically similar ungulate species.

We describe the shape variability of nine dog hemimandibles recovered from two Holocene archaeological sites on the Iberian Peninsula. In this study we mainly focus on the Chalcolithic age dog remains recovered from Barrio del Castillo (Torrejon de Ardoz, Madrid), but also, make comparisons to dog specimens from El Portalon (Sierra de Atapuerca, Burgos) Bronze Age. We used geometric morphometrics (3D) to describe mandibular morphology and compared these specimens with a modern sample of Iberian wolves, dogs, and red foxes. As complete mandibles are rarely found in the archaeological record, we also analysed the variability of the shape on fragments of mandibles. Here, we examine if there is morphological variability or a continuity in size between Chalcolithic and Bronze Age dogs. A scenario of very similar dogs, with a continuity in the size, is expected in the inner regions of the peninsula in contrasts with the coastal sites (influenced by a higher commercial activity). Our results suggest a continuity in the size and morphology of M1. These dogs still conserved diagnostic wolf traits in relation to the carnassial zone. Additionally, we observe that the region behind the M1 in Chalcolithic and Bronze Age dogs is slightly different when we analysed the fragmentary mandibles.

Studies of Rancho La Brea predators have yielded disparate dietary interpretations when analyzing bone collagen vs. enamel carbonate—requiring a better understanding of the relationship between stable carbon isotopes in these tissues. Stable carbon isotope spacing between collagen and carbonate (Δca-co) has also been used as a proxy for inferring the trophic level of mammals, with higher Δca-co values indicative of high carbohydrate consumption. To clarify the stable isotope ecology of carnivorans, past and present, we analyzed bone collagen (carbon and nitrogen) and enamel carbonate (carbon) of extinct and extant North American felids and canids, including dire wolves, sabertooth cats, coyotes, and pumas, supplementing these with data from African wild dogs and African lions. Our results reveal that Δca-co values are positively related to enamel carbonate values in secondary consumers and are less predictive of trophic level. Results indicate that the foraging habitat and diet of prey affects Δca-co in carnivores, like herbivores. Average Δca-co values in Pleistocene canids (8.7+/−1‰) and felids (7.0+/−0.7‰) overlap with previously documented extant herbivore Δca-co values suggesting that trophic level estimates may be relative to herbivore Δca-co values in each ecosystem and not directly comparable between disparate ecosystems. Physiological differences between felids and canids, ontogenetic dietary differences, and diagenesis at Rancho La Brea do not appear to be primary drivers of Δca-co offsets. Environmental influences affecting protein and fat consumption in prey and subsequently by predators, and nutrient routing to tissues may instead be driving Δca-co offsets in extant and extinct mammals.

Here we report the preliminary results from the 2015-19 s prospecting explorations, excavations, and research from Juan Labranz Cave, a new Quaternary palaeontological deposit rich in mammals that offers information on the faunal context of the southern sub-plateau. This cave is located on the border of the Iberian range, at the Sierra de Valdecabras, Cuenca, at 1.279 metres above sea level. This study includes the first georeferenced digital map of the cave and a preliminary analysis of its chronology, palynology, macro- and microvertebrate palaeontology, and taphonomy. The cave is interpreted as a hyena den, and this would represent one of the highest elevation cavities where the activity of this taxon is recorded. Moreover, we consider this site important and unique because it constitutes one of the very few Pleistocene cave sites in the southern sub-plateau. It is strategically located on the border between the Iberian range and the Tajo Tertiary Basin, at the Jucar River valley, which represents the only great natural corridor that covers hundreds of kilometres and connects two very important palaeoecological areas, the interior of the Iberian Peninsula and the Mediterranean basin.

The scimitar-toothed cat Homotherium was one of the most cosmopolitan cats of the Pleistocene, present throughout Eurasia, Africa, and the Americas until at least similar to 28 thousand years ago.(1-3)Friesenhahn Cave (Bexar County, Texas) contains some of the best-preserved specimens of Homotherium serum alongside an abundance of juvenile mammoths, leading some to argue that H. serum preferentially hunted juvenile mammoths.(1,4) Dietary data of Homotherium are rare, with their ecology inferred from morphological, taphonomic, and genetic data.(1,3-10) Here, we use a multi-proxy approach to clarify the dietary ecology of H. serum as compared to extinct and extant cats and their relatives. Dental microwear texture analysis (DMTA) reveals that H. serum consumed soft and tough foods, similar to the extant cheetah, which actively avoids bone,(11,12) but in stark contrast to extant lions and hyenas, which are observed to engage in durophagy (i.e., bone processing).(11-14) DMTA data are consistent with taphonomic evidence of bone defleshing and the absence of bone-crunching behavior in H. serum. Stable carbon isotope values of H. serum indicate a clear preference for C-4 grazers including juvenile mammoths, in agreement with taphonomic evidence suggestive of a "Homo-therium den''(1,4) and morphological data indicative of a relatively cursorial lifestyle.(6-8) Notably, the inferred diet of H. serum contrasts with the extinct dirk-tooth sabertooth cat Smilodon fatalis, which preferred forest/woodland prey and engaged in bone processing.(15-19)Homotherium serum exhibited a novel combination of morphological adaptations for acquiring open-country prey, consuming their soft and tough flesh- including the tough flesh of juvenile mammoths.

ABSTRACTThe late Pleistocene to early Holocene Champlain Sea provides a unique opportunity to study the development of marine ecosystems in a context of global climatic change. This study presents radiocarbon (14C) dates and stable isotope analyses on 15 vertebrate specimens from Champlain Sea sediments, including the Charlotte Whale, which is Vermont’s State marine fossil. Data are used in an attempt to investigate the timing of colonization and ecological dynamics in this newly formed sea. Using the average marine correction,14C dates on four specimens likely calibrate prior to or possibly synchronous with the accepted origination date for the Champlain Sea, implying larger marine reservoir effects than the average marine correction in the vertebrate tissues. Without knowing the specific marine reservoir offsets, it is not possible to calculate the timing of colonization or its relation to concurrent climatic change. Observed lower δ13C and δ15N values in walruses, a fin whale, and a right whale support consumption of prey from lower trophic levels such as bivalve mollusks, krill, and copepods. Higher isotopic values in beluga whales and a bird, the thick-billed murre, support consuming fish, such as cod and capelin. These isotopic data show comparable values and relationships as observed in modern arctic marine ecosystems.

The Northborough Mastodon (Mammut americanum), discovered in central Massachusetts in 1884, has never been dated. We have obtained a high precision AMS radiocarbon age on collagen from a tusk: 11,350 ± 30 rcbp (UCIAMS 225612), ca. 13,200 cal BP. We review the circumstances of the discovery and discuss the implications of the new date and isotopic data with regard to mastodon ecology, their colonization of New England, their coexistence with humans, and their extinction at the end of the Pleistocene.

Native Americans developed agronomic practices throughout the Western Hemisphere adapted to regional climate, edaphic conditions, and the extent of dependence on agriculture for subsistence. These included the mounding or “corn hill” system in northeastern North America. Iroquoian language speakers of present-day New York, USA, and Ontario and Québec, Canada were among those who used this system. While well-known, there has been little archaeological documentation of the system. As a result, there is scant archaeological evidence on how Iroquoian farmers maintained soil fertility in their often-extensive agricultural fields. Using δ15N values obtained on fifteenth- and sixteenth-century AD maize kernels from archaeological sites in New York and Ontario, adjusted to take into account changes that result from charring as determined through experiments, we demonstrate that Iroquoian farmers were successful at maintaining nitrogen in their agricultural fields. These results add to our archaeological knowledge of Iroquoian agronomic practices. Our results also indicate the potential value of obtaining δ15N values on archaeological maize in the investigation of Native American agronomic practices.

DeSantis et al. respond to the concerns raised by Van Valkenburgh et al. on their original study.

Domestic cats preying on wildlife is a frequent conservation concern but typical approaches for assessing impacts rely on owner reports of prey returned home, which can be biased by inaccurate reporting or by cats consuming prey instead of bringing it home. Isotopes offer an alternative way to quantify broad differences in animal diets. By obtaining samples of pet food from cat owners we predicted that we would have high power to identify cats feeding on wild birds or mammals, given that pet food is thought to have higher C isotope values, due to the pervasive use of corn and/or corn by-products as food ingredients, than native prey. We worked with citizen scientists to quantify the isotopes of 202 cat hair samples and 239 pet food samples from the US and UK. We also characterized the isotopes of 11 likely native prey species from the southeastern US and used mixing models to assess the diet of 47 cats from the same region. Variation in C and N isotope values for cat food was very high, even within the same brand/flavor, suggesting that pet food manufacturers use a wide range of ingredients, and that these may change over time. Cat food and cat hair from the UK had lower C values than the US, presumably reflecting differences in the amount of corn used in the food chains of the two countries. This high variation in pet food reduced our ability to classify cats as hunters of native prey, such that only 43% of the animals could be confidently assigned. If feral or free ranging cats were considered, this uncertainty would be even higher as pet food types would be unknown. Our results question the general assumption that anthropogenic foods always have high C isotope values, because of the high variability we documented within one product type (cat food) and between countries (US vs. UK), and emphasize the need to test a variety of standards before making conclusions from isotope ecology studies.

We assess diet and economies of middle Holocene (∼7,500 to 4,000 calibrated [cal] B.P.) humans at coexisting mound sites (Huaca Prieta and Paredones) in north coastal Peru and document regular consumption of maize by ∼6,500 to 6,000 cal B.P. and its earliest use as a staple food in this area of the Andes between 5,000 and 4,500 cal B.P. Stable isotope data from enamel carbonates and dentin collagen (childhood diet) and dental microwear texture analysis (adult diet) demonstrate dietary and economic specialization. Previous studies revealed maize and mixed-food refuse at both sites, but this study documents actual food consumption, showing that these communities situated a few hundred meters apart had significantly distinct diets in childhood and adulthood. Huaca Prieta focused on marine resources, although there are some contributions from terrestrial meat. Paredones individuals primarily consumed maize during childhood (up to 70% of the juvenile diet), as shown by δ13C values, apatite-collagen spacing, and discriminant analysis of δ13Ccoll, δ13Ccarb, and δ15N values. Maize was likely used as a weaning food (e.g., gruel and/or chicha-a maize beverage), hinting at the significant role of breastfeeding mothers, weanling infants, and children in the development of maize as a staple crop. Additionally, dental microwear data show Paredones adult diets are high in abrasives, potentially from maize processing. The distinct foodways at these neighboring sites result from and also reflect their social and political distinctions. These differences in food production, distribution, and consumption generated opportunities for exchange, an interaction that bound them together in mutual benefit.

1 Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina, United States 2 North Carolina Museum of Natural Sciences, Raleigh, North Carolina, United States 3 Department of Applied Ecology, North Carolina State University, Raleigh, NC, United States 4 Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark 5 Center for Ecology and Conservation, University of Exeter, Penryn, United Kingdom 6 New York State Museum, Albany, New York, United States