Allo-suckling occurrence and its effect on lactation and nursing duration in harbour seals (Phoca vitulina) in Orkney, Scotland

This study was funded by Scottish Government (grant number MMSS/002/15).Fostering and allo-suckling are widespread among pinnipeds, and several hypotheses have been formulated to explain their occurrence. Here, we describe the occurrence of allo-suckling in harbour seals from photo-identification data of females and pups in Orkney (Scotland) during the pupping seasons between 2016 and 2019. We used a generalised linear model framework to investigate the effect of allo-suckling on the duration of lactation (females) and of nursing period (pups). A generalised additive model framework was used to explore how the probability of allo-suckling varied throughout the pupping season, and with changes in mother-pup separation time. Allo-suckling was observed in 31 females, at higher rates (18–37% of lactating females and 18–47% of the pups every year) than those observed in other phocid populations, with 13 females allo-suckling in multiple years. The duration of the pups’ nursing period was not affected by allo-suckling occurrence. However, females in mother-pup pairs where both mother and pup allo-suckled had longer lactation duration than when only the pup allo-suckled, or than in pairs where no allo-suckling was observed. The probability of allo-suckling increased during the pupping season and with increased mother-pup separation time. However, the proximate causes and the consequences on future reproductive output and pup survival remain unknown.Publisher PDFPeer reviewe

Sex-related differences in the postmolt distribution of Weddell seals (Leptonychotes weddellii ) in the southern Weddell Sea

The population of Weddell seals (Leptonychotes weddellii) in the southern Weddell Sea is in a unique position on the continental shelf edge, with vast shelf waters to the south, and deep Southern Ocean to the north. We describe sex-related differences in the winter distribution of this population, from data collected by 20 conductivity-temperature-depth satellite relay data loggers deployed in February 2011 at the end of the annual molt. The regional daily speed was calculated, and a state-space model was used to estimate behavioral states to positions along individuals’ tracks. GLMMs estimated that males and smaller individuals, diving in shallower water, traveled less far per day of deployment (males 14.6 ± 2.26 km/d, females 18.9 ± 2.42 km/d), and males were estimated to dive in shallower water (males 604 ± 382 m, females 1,875 ± 1,458 m). Males and smaller individuals were also estimated to be more resident; males spent an average 83.4% ± 7.7% of their time in a resident behavioral state, compared to females at 74.1% ± 7.1%. This evidence that male and female Weddell seals in the southern Weddell Sea are adopting different strategies has not been shown elsewhere along their circumpolar distribution

Site use and connectivity of female grey seals (Halichoerus grypus) around Wales

The UK Natural Environment Research Council (NERC) provided core funding to the Sea Mammal Research Unit during this work and NERC Grant No. NE/G008930/1 to PP and LH to develop photo-ID use for grey seals. The Esmée Fairbairn Foundation provided additional funding to PP and LH for photo-ID work with grey seals. NRW funded survey work by MB, LM, SW and PS; contracted LH for survey design, software development and data management; IL and PP for work related to the production of this manuscript.Grey seals (Halichoerus grypus) are a qualifying feature of three special areas of conservation (SACs) in Wales, yet relatively little is known of their site use along this coastline. Since 1992, many individuals and organisations have contributed to a grey seal photographic identification database held by Natural Resources Wales, which is one of the largest and oldest of its kind, providing key information from grey seal haul-out sites around the Celtic and Irish Seas. Here, we investigated spatial connectivity of haul-out sites and fidelity of adult females to breeding sites. The minimum number of adult female grey seals using the area between 1992 and 2016 was 2688. Individual capture histories and relative spatial transition probabilities (Pij) between pairs of location groups were calculated. Adjacent locations were highly connected (e.g. Lleyn Peninsula and Bardsey, Pij = 0.7) but connections spanned the entire region, up to 230 km apart (e.g. Skomer and Dee Estuary, Pij = 0.004). Resights were recorded within SACs (e.g. Lleyn Peninsula and Bardsey [Lleyn Peninsula and the Sarnau SAC], Pij = 0.7), between SACs (e.g. Bardsey and Skomer [Pembrokeshire Marine], Pij = 0.03), between SACs and non-designated areas (e.g. Skerries and Bardsey, Pij = 0.09) and between sites outside any protected area (e.g. Dee Estuary and Anglesey, Pij = 0.5). While inter-annual fidelity to breeding sites was high (Pij = 0.82–1), individual female grey seals moved throughout the region. This evidence of extensive site use beyond protected areas is important for the management and conservation of grey seals around Wales.Publisher PDFPeer reviewe

Have you got the tine? Prehistoric Methods in Antler Working

Antler working was prevalent throughout prehistory, with a breadth of intricately detailed and technologically complex antler artefacts observed within the archaeological record. In particular, during the Palaeolithic, Mesolithic, and Neolithic, antler working with flint tools would have been a time-consuming process. While the chaîne opératoire of producing certain antler artefacts has previously been explored (Elliott and Milner, 2010; Marquebielle, 2011; Langley, 2014) there is a debate surrounding whether the soaking of antler was a necessary stage in this process. Soaking antler as a part of the chaîne opératoire is yet to be explored in depth, and thus the full implications of this stage to antler working processes in prehistory have not been considered. Where soaking antler has been explored, no distinction is made between soaking antler beams whole (for example, with no prior modification) or soaking antler which has had tines removed to expose the interior of the antler. We present the results of experiments which tested whether there is a significant difference between the workability of dry, soaked-whole antler, and soaked-exposed antler. We argue that there is a missing stage in current understandings of the chaîne opératoire of antler artefact manufacture. We conclude this stage could be responsible for the observed deposits of tine-removed antler in wetlands at prehistoric sites, such as Star Carr

Assessing the performance of open-source, semi-automated pattern recognition software for harbour seal (P. v. vitulina) photo ID

Data collection was funded by the Scottish Government (grant number MMSS/002/15)Photographic identification (photo ID) is a well-established, non-invasive, and relatively cost-effective technique to collect longitudinal data from species that can be individually recognised based on natural markings. This method has been improved by computer-assisted pattern recognition software which speed up the processing of large numbers of images. Freely available algorithms exist for a wide range of species, but the choice of software can have significant effects on the accuracy of individual capture histories and derived demographic parameter estimates. We tested the performance of three open source, semi-automated pattern recognition software algorithms for harbour seal (Phoca vitulina vitulina) photo ID: ExtractCompare, I3S Pattern and Wild-ID. Performance was measured as the ability of the software to successfully score matching images higher than non-matching images using the cumulative density function (CDF). The CDF for the top ranked potential match was highest for Wild-ID (CDF1 = 0.34–0.58), followed by ExtractCompare (CDF1 = 0.24–0.36) and I3S pattern (CDF1 = 0.02–0.3). This trend emerged regardless of how many potential matches were inspected. The highest performing aspects in ExtractCompare were left heads, whereas in I3S Pattern and Wild-ID these were front heads. Within each aspect, images collected using a camera and lens performed higher than images taken by a camera and scope. Data processing within ExtractCompare took  > 4 × longer than Wild-ID, and  > 3 × longer than I3S Pattern. We found that overall, Wild-ID outperformed both ExtractCompare and I3S Pattern under tested scenarios, and we therefore recommend its assistance in harbour seal photo ID.PostprintPeer reviewe

Art by firelight? Using experimental and digital techniques to explore Magdalenian engraved plaquette use at Montastruc (France)

Palaeolithic stone plaquettes are a type of mobiliary art featuring engravings and recovered primarily from Magdalenian sites, where they can number from single finds to several thousand examples. Where context is available, they demonstrate complex traces of use, including surface refreshing, heating, and fragmentation. However, for plaquettes with limited or no archaeological context, research tends to gravitate toward their engraved surfaces. This paper focuses on 50 limestone plaquettes excavated by Peccadeau de l’Isle from Montastruc, a Magdalenian rockshelter site in southern France with limited archaeological context; a feature common to many art bearing sites excavated across the 19th and early 20th Centuries. Plaquette use at Montastruc was explored via a programme of microscopy, 3D modelling, colour enhancement using DStretch©, virtual reality (VR) modelling, and experimental archaeology, the latter focusing on limestone heating related to different functional and non-functional uses. While the limited archaeological context available ensures the results remain only indicative, the data generated suggests plaquettes from Montastruc were likely positioned in proximity to hearths during low ambient light conditions. The interaction of engraved stone and roving fire light made engraved forms appear dynamic and alive, suggesting this may have been important in their use. Human neurology is particularly attuned to interpreting shifting light and shadow as movement and identifying visually familiar forms in such varying light conditions through mechanisms such as pareidolic experience. This interpretation encourages a consideration of the possible conceptual connections between art made and experienced in similar circumstances, such as parietal art in dark cave environments. The toolset used to investigate the Montastruc assemblage may have application to other collections of plaquettes, particularly those with limited associated context

Applicability of the semi-automated photo-identification software ExtractCompare for the monitoring of the harbour seals in Ireland

Photo-identification enables non-invasive identification of individuals from natural markings, with several algorithms developed to recognise individual patterns. ExtractCompare is a key software package for individual semi-automated recognition of harbour seals (Phoca vitulina). Its performance, however, may vary with image quality, aspect employed and subspecies. This study assessed ExtractCompare's applicability for monitoring harbour seals in Ireland where it has not been used previously, and explored the impact of aspect, pelage state and image parameters on performance. Test databases were created for the following aspects: head, neck, flank and head+neck. For each database, software performance was assessed by analysing 20 known matches and non-matches, respectively. The effect of parameters on performance was analysed using Generalised Linear Models, the Cumulative Density Function (CDF) was calculated for the first twenty ranked potential matching images, and similarity score thresholds were assessed against the relative frequency of false negatives. Results produced the first report of pelage state affecting the algorithm's accuracy, indicating that it should be considered for future studies. The CDF increased with the number of ranked images inspected (CDF1=0.35–0.60; CDF20=0.80–0.91). Our findings demonstrated the applicability of ExtractCompare for individual identification of harbour seals, indicating that this is a viable tool for monitoring this species in Irish waters

Allo-suckling occurrence and its effect on lactation and nursing duration in harbour seals (Phoca vitulina) in Orkney, Scotland (datasets)

The attached data files underpin the publication "Allo-suckling occurrence and its effect on lactation and nursing duration in harbour seals (Phoca vitulina) in Orkney, Scotland ". The data files are provided as .RData files that can be directly loaded into R software. The ReadMe.txt file provides details on definition of data fields within datasets

Allo-suckling occurrence and its effect on lactation and nursing duration in harbour seals (Phoca vitulina) in Orkney, Scotland (datasets)

The attached data files underpin the publication "Allo-suckling occurrence and its effect on lactation and nursing duration in harbour seals (Phoca vitulina) in Orkney, Scotland ". The data files are provided as .RData files that can be directly loaded into R software. The ReadMe.txt file provides details on definition of data fields within datasets