Dogs were domesticated at least once from a yet-unidentified wolf population at least ~15,000 y ago. However, how domestication took place is a topic of ongoing debate, and the ability of human groups to manage wolves in their communities during early stages of domestication is poorly understood. Here, we report multiproxy data from two canids excavated from Late Neolithic and Bronze Age contexts in the Stora Förvar cave on the island of Stora Karlsö in the Baltic Sea. The island is small (2.5 sq km) and, like the neighboring island of Gotland, carries no endemic populations of terrestrial mammals. Instead, the current consensus is that human introductions account for some mammal fauna on Gotland, and for the majority of that on Stora Karlsö. Genome-wide data show that the two canids have ancestry indistinguishable from Eurasian wolves, with no shared ancestry with domestic dogs of the Canis familiaris lineage. Their genome-wide heterozygosity is lower than that observed in 72 previously published ancient wolf genomes, and instead comparable to dogs. Stable isotope data (δ¹³C and δ¹⁵N) reveals a diet rich in marine protein, which is consistent with habitation alongside the human groups who used Stora Karlsö as a seal-hunting, fowling, and sea fishing station, and in the Bronze Age probably also for grazing. Skeletal size is at the lower end of wolf variability, and one individual shows advanced pathology consistent with reduced mobility. While other scenarios are possible, a parsimonious explanation is that these wolves were brought to the island by humans and were possibly under human control.

This study describes the development of a digital reporting system designed to provide archaeologists with a dynamic and interactive 3D web platform that can be used for describing in great detail records and activities undertaken across a multi-year field investigation campaign. The system was used to compose the archaeological report of a multi-year investigation and employed during the pandemic crisis for supporting digital courses in archaeological practice; the paper also reports the preliminary results of the use of this platform within teaching activities. Unlike other web solutions, this system supports an assisted publication of archaeological contents that integrates a 3D visualization system in the reporting process, exploiting the communicative potentials of 3D models and the web. This study represents a contribution to research on sustainable forms of management and publication of archaeological contents and their reuse and sharing.

Human behaviors from toolmaking to language are thought to rely on a uniquely evolved capacity for hierarchical action sequencing. Testing this idea will require objective, generalizable methods for measuring the structural complexity of real-world behavior. Here we present a data-driven approach for extracting action grammars from basic ethograms, exemplified with respect to the evolutionarily relevant behavior of stone toolmaking. We analyzed sequences from the experimental replication of similar to 2.5 Mya Oldowan vs. similar to 0.5 Mya Acheulean tools, finding that, while using the same alphabet of elementary actions, Acheulean sequences are quantifiably more complex and Oldowan grammars are a subset of Acheulean grammars. We illustrate the utility of our complexity measures by re-analyzing data from an fMRI study of stone toolmaking to identify brain responses to structural complexity. Beyond specific implications regarding the co-evolution of language and technology, this exercise illustrates the general applicability of our method to investigate naturalistic human behavior and cognition.

Ancient organic remains are essential for the reconstruction of past human lifeways and environments but are only preserved under particular conditions. Recent findings indicate that such conditions are becoming rarer and that archaeological sites with previously good preservation, are deteriorating. To investigate this, we returned to the well-known Swedish Mesolithic site Agerod I. Here we present the result of the re-excavation and the osteological analyses of the bone remains from the 1940s, 1970s and 2019 excavation campaigns of the site, to document and quantify changes in bone preservation and relate them to variations in soil conditions and on-site topography. The results indicate that the bone material has suffered from accelerated deterioration during the last 75 years. This has led to heavily degraded remains in some areas and complete destruction in others. We conclude that while Agerod can still be considered an important site, it has lost much of the properties that made it unique. If no actions are taken to secure its future preservation, the site will soon lose the organic remains that before modern encroachment and climate change had been preserved for 9000 years. Finally, because Agerod has not been subjected to more or heavier encroachment than most other archaeological sites, our results also raise questions of the state of organic preservation in other areas and call for a broad examination of our most vulnerable hidden archaeological remains.

Despite a growing body of evidence concerning accelerated organic degradation at archaeological sites, there have been few follow-up investigations to examine the status of the remaining archaeological materials in the ground. To address the question of archaeo-organic preservation, we revisited the Swedish, Mesolithic key-site Ageröd and could show that the bone material had been subjected to an accelerated deterioration during the last 75 years, which had destroyed the bones in the areas where they had previously been best preserved. To understand why this has happened and to quantify and qualify the extent of the organic degradation, we here analyse the soil chemistry, bone histology, collagen preservation and palaeobotany at the site. Our results show that the soil at Ageröd is losing, or has already lost, its preservative and buffering qualities, and that pH-values in the still wet areas of the site have dropped to levels where no bone preservation is possible. Our results suggest that this acidification process is enhanced by the release of sulphuric acid as pyrite in the bones oxidizes. While we are still able to find well-preserved palaeobotanical remains, they are also starting to corrode through re-introduced oxygen into the archaeological layers. While some areas of the site have been more protected through redeposited soil on top of the archaeological layers, all areas of Ageröd are rapidly deteriorating. Lastly, while it is still possible to perform molecular analyses on the best-preserved bones from the most protected areas, this opportunity will likely be lost within a few decades. In conclusion, we find that if we, as a society, wish to keep this valuable climatic, environmental and cultural archive, both at Ageröd and elsewhere, the time to act is now and if we wait we will soon be in a situation where this record will be irretrievably lost forever.

The summed probability distribution of 162 radiocarbon dates from Gotland was analysed with reference to archaeological and environmental data in order to evaluate possible variations in settlement intensity on the island. The data indicated variations in demographic development on the island, with probably several different colonization events and external influences; the pioneer settlement reached the island around 9200 cal. BP. After the initial colonization, the radiocarbon dates were rather evenly distributed until around 7700–7600 cal. BP, then there was a drop in the number of dates between 8300 and 8000 cal. BP that may be associated with the 8200 cold event. A marked decline in the number of dates between 7600 and 6000 cal. BP may be associated initially with the Littorina I transgression, but this transgression cannot explain why the Late Mesolithic period is not well represented on Gotland: the climatic development was favourable but did not result in increased human activity. The number of radiocarbon dates indicated that the population size remained low until around 6000 cal. BP, after which there was a gradual increase that reached a first ‘threshold’ after 5600 cal. BP and a second ‘threshold’ after 4500 cal. BP. The first apparent population increase was associated with the appearance of the Funnel Beaker Culture (FBC) and the second with Pitted Ware Culture (PWC) complexes. A decline in the number of dates occurred after 4300 cal. BP, i.e. towards the Late Neolithic. There was an association between the frequency distributions of the radiocarbon dates and the number of stray finds from different time periods but any correlation was not straightforward.

In this paper we explore the subsistence economy of the Mesolithic pioneers on the island of Gotland in the Baltic basin, in order to evaluate the importance of freshwater fish to the Early Holocene human population. By analysing faunal remains, the distribution of ¹⁴C dates and the location of the settlement sites, we argue that earlier assumptions concerning the importance of marine mammals to the early human populations should be reconsidered. We suggest that the pioneering settlers of Gotland relied on fish to a significant extent. Radiocarbon dates taken from human bones are skewed by a freshwater reservoir effect, which can be used as an indirect indication of the significance of freshwater fish. The numerous, overgrowing lakes on the island, with their extensive biomass production and large amounts of freshwater fish, provided an important subsistence base. Even if the faunal assemblages that have survived are dominated by seal bones, the hunting season for seals was limited and the hunters mostly targeted young seals. Thus, the importance of seal have previously been overestimated and it appears that the human use of marine resources on Gotland was more limited and related to raw material needs rather than dietary necessity or specialization. Although presented as a case study; the results highlight the need to identify a freshwater fish diet among ancient foragers on a larger scale, as implications thereof can fundamentally change how foraging societies are perceived.