Small Cave Research Articles

CO<sub>2</sub> hypogene speleogenesis in an endogenic travertine system, Mesa del Oro, New Mexico, USA

The Mesa del Oro travertine, deposited by upwelling CO2-rich spring waters, is a large and thick mantle of calcite overlying soft Triassic Chinle Formation mudstones in western central New Mexico, USA. The travertine contains a system of small caves known as the Pronoun Cave Complex. Whut Cave is the largest known cave in the complex. While the travertine hydrologic system is no longer active, there is ample evidence that Whut Cave was formed by hypogene speleogenesis. The Whut Cave entrance is a small roughly circular shaft that descends ~four meters and intersects a linear fissure-controlled passage. Mn-oxide was once mined below the entrance, leaving a five-meter-deep pit that represents the path of upwelling waters that were likely charged with CO2 and supersaturated with CaCO3 once reaching the surface. The roomiest part of the cave is immediately adjacent to the entrance, defining where most of the upwelling of groundwater and gases took place. Gypsum and other sulfates were only noted microscopically. A sample of travertine at the surface near the entrance yielded a uranium-series age beyond the limit of the method and a δ234U age of 735 ± 109 ka BP (before present). A piece of breccia vein in the mine dump associated with the Mn-oxide ore, and a rill of a drape-like crust on the cave wall, both interpreted to be products of hypogene speleogenesis and representing the oldest speleogenetic material, yielded δ234U ages of 848 ± 110 and 723 ± 109 ka BP. Altogether, materials interpreted to be speleogenetic yielded ages of ~900 – 300 ka BP. Although the cave is dry and hydrologically inactive today, cave development by CO2 hypogene speleogenesis was coeval with endogenic travertine deposition and nearby volcanism. Our interpretation suggests that all these events are linked.

Phalacrocorax bakonyiensis n. sp., a new species of cormorant from the Late Miocene of Hungary

Abstract We describe Phalacrocorax bakonyiensis n. sp. an extinct member of the cormorants (Phalacrocoracidae). The fossil was found in 2021 by geologist János Futó in the sediments of a small cave cavity on the side of Várhegy in Sümeg, a part of the Bakony Mountains of West Hungary, where Late Miocene (MN11–12) vertebrate fossils have been found in the past decades. The total number of bone fragments collected was 14, of which only three can be identified. Two of these belong to adults and one, due to its poor preservation and size, to a very young specimen.

Integrative taxonomy reveals first record of Loxoscelesrufescens (Dufour, 1820) (Araneae, Sicariidae) in the Philippines.

The spider family Sicariidae Keyserling, 1880 represented by the synanthropic Mediterranean recluse spider, Loxoscelesrufescens (Dufour, 1820), is reported in the Philippines for the first time, based on morphological and molecular data. The introduced spider was observed in a small cave (Kamantigue Cave) in Lobo, Batangas Province. Considering the medical importance of this spider, the proximity of its habitat to human habitation and tourist sites poses a potential public health concern. This study reports on the first record of the family Sicariidae in the Philippines and the fourth recorded occurrence of L.rufescens in Southeast Asia.

Phylogenetic systematics of the enigmatic genus Horologion Valentine, 1932 (Coleoptera, Carabidae, Trechinae, Horologionini), with description of a new species from Bath County, Virginia

Horologion Valentine, one of the rarest and most enigmatic carabid beetle genera in the world, was until now known only from the holotype of Horologion speokoites Valentine, discovered in 1931 in a small cave in West Virginia. A single specimen of a new species from Virginia was collected in 1991, but overlooked until 2018. DNA sequence data from specimens of this new species, Horologion hubbardisp. nov., collected in 2022 and 2023, as well as a critical examination of the external morphology of both species, allow us to confidently place Horologion in the supertribe Trechitae, within a clade containing Bembidarenini and Trechini. A more specific placement as sister to the Gondwanan Bembidarenini is supported by DNA sequence data. Previous hypotheses placing Horologion in or near the tribes Anillini, Tachyini, Trechini, Patrobini, and Psydrini are rejected. The existence of two species of Horologion on opposite sides of the high mountains of the middle Appalachians suggests that these mountains are where the ancestral Horologion populations dispersed from, and predicts the discovery of additional populations and species. All specimens of H. hubbardi were collected in or near drip pools, and most were found dead, suggesting that the terrestrial epikarst, rather than caves, is the true habitat of Horologion, which explains their extreme rarity since epikarst has not been directly sampled. We recognize the tribe Horologionini, a relict lineage without any close relatives known in the Northern Hemisphere, and an important part of Appalachian biodiversity.

The Grumpy dwarfgoby, a new species of Sueviota (Teleostei, Gobiidae) from the Red Sea.

A new gobiid species is described from ten specimens, 9.2 - 16.7 mm SL, collected from the Saudi Arabian Red Sea. The new species is most similar to Sueviotapyrios from the Gulf of Aqaba in the northern Red Sea. It differs from S.pyrios by having no large red spots on the dorsal and caudal fin elements, no elongate spines in the first dorsal fin, a shorter pelvic fin that does not reach the anus, branched pectoral fin rays, and a projecting lower jaw. The new species is further distinguished from all its congeners by a complete lack of cephalic sensory canals and pores. Specimens were found in small caves and overhangs at depths between 10 and 53 meters.

Cave Levels in the Totes Gebirge (Eastern Alps)

Abstract The Totes Gebirge is not only the largest karst massif in the Northern Calcareous Alps, it also contains the most cave passages. In this area we are investigating the vertical distribution of phreatic cave passages to determine cave levels. These are vertical zones with clusters of cave passages that can be correlated with former valley floors. Since only phreatic cave passages (i.e. caves that were permanently or episodically filled with water during their formation) are to be analysed, a genetic classification is made on the basis of field observations, cave maps, 3D surveys and descriptions. As of Sept. 2023, the Totes Gebirge range, including the adjacent Warscheneck and the Hohe Schrott, contains 3172 known caves with a total length of 821 km, including the two longest cave systems in Austria, the Schönberg- (156 km) and the Schwarzmooskogel-Höhlensystem (137 km). As small caves do not contribute significantly to these statistics, only caves ≥50 m were included. The remaining 754 caves have a total length of 790 km. Only 46 % of these caves are at least partially of phreatic origin, but they contain 92 % of the total passage length. After subtracting the caves from which no data were available and cave sections that are not phreatic in origin (i.e. vadose or those created by weathering and erosion), 641 km of cave sections remained, which were analysed for their vertical distribution in 25 m increments. The histogram of cave length distribution vs. elevation for the Totes Gebirge range shows only a single significant cluster of phreatic cave sections between 1300 and 1850 m above see level (a.s.l.), with a clear maximum at 1500 m. The massif was divided into four sub-regions and all of them show this main interval, which is why it was interpreted as a cave level. It correlates well with the Giant Cave Level known from all other karst massifs in the Northern Calcareous Alps analysed so far. However, it is peculiar that in the other massifs at least three cave levels are present. Other reasons, such as the lack of known caves and the large size of the massif, which could lead to overlapping of cave levels, are unlikely. Therefore, it seems possible that the palaeo surface drainage pattern around the Totes Gebirge or its uplift history was different from the other karst massifs in the Northern Calcareous Alps and that low-lying cave levels (Spring and Berger Cave Level) or an elevated one (Ruin Cave Level) did not develop. For each of the 21 largest cave systems (≥5 km in length), the peak of the vertical distribution of the phreatic passages was determined. Vectors were calculated in order to test whether palaeo-flow directions could be inferred from their distribution. These phreatic maxima indicate a general dip from ESE to WNW, which could be interpreted either as a palaeo-drainage direction or as a tectonic tilting of the whole massif after the formation of the passages.

Pozoruhodne vysoký vek netopiera brvitého (Myotis emarginatus) a netopiera Brandtovho (Myotis brandtii) na Slovensku (Chiroptera: Vespertilionidae)

Remarkably high age found in Myotis emarginatus and Myotis brandtii from Slovakia (Chiroptera: Vespertilionidae). New longevity records of the Geoffroy’s bat (Myotis emarginatus) and Brandt’s bat (Myotis brandtii) were made in eastern Slovakia with the help of ringing. The minimum age of twenty years and two months was evidenced for a Myotis emarginatus individual re-captured at a small cave near Beňatina in the Východné Beskydy Mts. on 2 September 2016 (first caught and ringed at the same site on 2 August 1996). It is the second highest age found in this bat from Slovakia, where the known longevity maximum is 22 years and eight months. In Myotis brandtii, the minimum age of 28 years was recorded, when a male was netted in a forest near Priekopa in the Vihorlat Mts. on 12 August 2022 that was first caught and ringed at a very close site on 14 August 1994.

Diet of the Small Cave Bear Ursus (Spelaearctos) rossicus Borissak, 1930 (Mammalia, Carnivora, Ursidae) As Revealed by 13C and 15N Isotope Analyses in Bone Collagen.

The 13C and 15N isotope contents in bone collagen were analyzed using bones of the small cave bear Ursus (Spelaearctos) rossicus Borissak, 1930 from localities in the Middle and Southern Urals. The bones date from the last interglacial (MIS 5) and glacial (MIS 3) periods. The bones were from males and females aged 3, 4, and >4 years. Sexual, geographical, and chronological differences in 13C and 15N contents were studied. Notable gender, geographic, and chronological differences were observed between samples. In the Middle Urals, females led a more predatory lifestyle than males during the interglacial period, and the trophic niches of males and females converged due to an increase in herbivory during the transition to the glacial period. In the Southern Urals, males led a more predatory lifestyle than in the Middle Urals during the interglacial period. The extent of changes in δ13C and δ15N values in the Southern Urals during the transition was found to correspond to differences between trophic levels.

Collagen Contents of 13С and 15N Isotopes in Bones of Small Cave Bear Ursus (Spelaearctos) rossicus Borissiak, 1930 (Mammalia, Carnivora, Ursidae) from Western Siberia.

The 13C and 15N isotope contents in collagen were determined in bones of the small cave bear Ursus (Spelaearctos) rossicus Borissiak, 1930 from three regions of Western Siberia. The bones dated back to marine isotope stage (MIS) 3 and belonged to mature males and females. Some of the samples differed only in δ15N. Bears of all samples were from the same trophic level. Trophic shifts were observed between females and males in one region and between males of two regions. The small cave bear of Western Siberia differed from the small cave bear of the Southern Urals in leading a much more predatory lifestyle. The extent of differences between the Ural and Siberian bears corresponded to different trophic levels.

Two species of the genus Psechrus Thorell, 1878 (Araneae: Psechridae) from North Sumatra, Indonesia

A new species, Psechrus leshukovi sp. n., is described from Sumatra Island (Indonesia) based on males collected in small caves. It is closely related to P. singaporensis Thorell, 1894, known from Southeast Asia, but differs from the latter by the shape of male palp. The female of P. libelti Kulczyński, 1908, collected in the same systems of grottos, is redescribed.

From Chalcolithic to Early Bronze Age: A view from Abu Hof Cave 22 (Israel)

Archaeological cultural taxonomy is a practical necessity. It singles out more or less coherent patio-temporal entities and facilitates scholarly exchange and communication. However, these practical conventions tend to take an independent life of their own, and sometimes constrain creative research endeavors. It is well known that ―the name is not the thing‖. Archaeological cultural taxa are relatively flexible entities, not perfectly self-contained units. Despite this realization, change documented from one archaeological culture to the next is generally framed in term of ‗transition‘, a legacy of classic gradualism. This paper addresses the issues of change and the nature of the Chalcolithic/Early Bronze Age interface in the Southern Levant, from the vantage point of a small cave located in the Nahal Tillah valley in Northern Negev, Israel. Genomic and intra-site archaeological data suggest the situation to be a robust illustration of punctuated equilibrium, without evidence of continuity between the ending Chalcolithic and the emerging Early Bronze Age societies.

Integration of direct radiocarbon dating, genetic studies and taxonomy of small mammals to investigate the chronology of past climatic oscillations: The Last Glacial Maximum sequence of Grotta della Ferrovia (Fabriano, Italy)

The recent developments in palaeoecological reconstruction methods, collagen extraction of small bone samples and ancient DNA analyses led us to test new approaches to enhance the chronological resolution of past climate reconstructions inferred from small mammal assemblages.Grotta della Ferrovia (Fabriano, Ancona, Italy, 40°25′36″N, 13°0′11″E, 215 m a.s.l.) is a small cave that opens on the southern bank of the Esino river, around 45 km west of Ancona. Discovered in 1966, it is famous among scholars because it is the first locality where the fossil birch mouse was recorded in Italy and because of the remarkable archaeological lithic evidence assemblage found in the cave related to the Late Epigravettian. Across the small mammal sequence, distributed into seven layers (from GDF7 to GDF2), two main phases can be recognized: in the first phase, from GDF7 to GDF5, Microtus arvalis is dominant over Microtus agrestis, in a poorly diversified assemblage. The sequence gradually changes in GDF4 and a second phase can be observed in GDF3 and GDF2, where Apodemus gr. sylvaticus-flavicollis dominates, but combined with a higher number of taxa. From GDF7 to GDF3, few individuals of Sicista cf. subtilis and Alexandromys oeconomus are recorded. Environmental and climatic reconstructions calculated with the Habitat Weighting and the Bioclimatic methods show a dominance of open meadows (GDF7 to GDF4) that were gradually replaced by closed or semi-closed forests (GDF3 and GDF2) in a context of gradually increasing temperature, shifting from a cold phase to conditions similar to the current ones in the area.Direct radiocarbon dates on 18 rodent bones and aDNA analyses on three Microtus arvalis teeth helped us to better understand the significance of the oscillation inferred from the small mammal sequences. A robust series of nine radiocarbon measurements from GDF7 to GDF5 shows that this part of the sequence accumulated between ∼24,600–19,600 cal BP (95.4% probability), which includes the final phases of the Last Glacial Maximum (LGM). The ancient DNA from Microtus arvalis confirmed the chronological framework and the presence of italic populations in this area during the LGM, similar to the slightly more ancient Grotta del Sambuco on the western side of the central Peninsula. The small mammal radiocarbon dates from GDF4 and above are less consistent with their stratigraphic position, probably related to post-depositional disturbance of the sediments, but suggest that the last part of the sequence accumulated during the Late Glacial.Our results show that it is now possible to validate and enhance paleoclimatic and paleoenvironment inferences from small mammal sequence studies with direct radiocarbon dates and ancient DNA analyses, using these integrated methods as a high resolution tool for studying the past.

Deep mtDNA Sequence Divergences and Possible Species Radiation of Whip Spiders (Arachnida, Amblypygi, Phrynidae, Phrynus/Paraphrynus) among Caribbean Oceanic and Cave Islands

Islands—whether classic oceanic islands or habitat islands such as isolated thermal vents, mountain tops, or caves—often promote the diversification of lineages that colonize them. We examined CO1 mtDNA sequence divergences within the tailless whip spider genus Phrynus Lamarck, 1809 (Amblypygi: Phrynidae) among oceanic islands and among cave ’islands´ distributed across the Caribbean archipelago and on the continental mainland. The significance of this study lies in the extensive taxon sampling of a supposedly depauperate lineage (considering its age), over a large proportion of its geographical range, and the discovery of deep mtDNA sequence divergences. We sampled thousands of specimens—and sequenced 544, including six outgroup species—across 173 localities on 17 islands (135 localities) and five countries on the North to South American mainland (38 localities), including a total of 63 caves. Classical taxonomy identified ten named Phrynus and two Paraphrynus Moreno, 1940 species. Paraphrynus seems to be paraphyletic and nested in Phrynus. Uncorrected genetic distances within named species and among morphological species ranged up to 15% and 19%, respectively. Geographic distances explained a significant portion of genetic distances on islands (19%, among both subterranean and epigean specimens), and for epigean specimens on the mainland (27%). Species delimitation analyses indicated that the 12 named species harbored from 66 to well over 100 putative species. The highest number of species was indicated by the GMYC method (114 species) while the Bayesian Poisson tree processes (bPTP) and the BP&P relying on the Markov chain Monte Carlo Bayesian Phylogenetic model estimated an upper level of 110 species. On the other hand, the recently recommended and relatively conservative distance-based (phylogeny free) ASAP model has the greatest support for 73 species. In either case, nearly all putative species are tightly limited to a single locality, often a small cave system, and sometimes to the surrounding epigean area. Caribbean Phrynus diversity has likely been vastly underestimated, likely due to both morphological crypsis and the ignorance of Caribbean cave fauna. Although mtDNA sequences can suggest species limits, nuclear DNA sequencing and detailed morphological research are necessary to corroborate them and explore whether this phenomenon constitutes species radiation or perhaps just mtDNA divergences as a consequence of, for example, stationary females and actively dispersing males.

Storage and distribution of organic carbon in cave sediments: examples from two caves in the northern karst region of Puerto Rico.

The clastic sediments that accumulate in cave settings can be an important storage reservoir for organic carbon. This study reports on grain size, total organic carbon (TOC) concentrations, and total organic carbon:total organic nitrogen (TOC:TON) ratios measured in sediments from two caves in Puerto Rico. El Tallonal Cave (TAL) is a small cave with a flowing stream; the sediments in TAL were collected from a deposit that is being actively eroded. Clara Cave (CAM) is an upper level of the Río Camuy Cave System; the sediments from CAM were newly deposited by an internal river that rose in response to Hurricane Maria. Sediments collected from both caves were poorly sorted and contained no apparent stratigraphic correlation. CAM sediments contained a larger range in TOC concentrations but were overall lower than TOC in the TAL sediments. In TAL, the TOC concentrations were higher in sediments collected from below the erosional terrace. TOC:TON ratios from sediments at both caves were highly variable, highlighting the heterogeneous deposition and storage of organic matter. Despite the observed variation, TOC concentrations in both cave systems could cause retardation of organic contaminants by up to two orders-of-magnitude, implying that deposited sediments influence the fate of organic contaminants in the groundwater; therefore, cave sediments could facilitate long term storage of organic carbon and associated contaminants.

New Efficient Method for Hysteroscopic Isthmoplasty: Four Simple Steps Lead to a Significant Improvement in Bleeding Status.

We demonstrate an effective reduction in postmenstrual spotting after our novel hysteroscopic isthmoplasty. This study included 66 patients with isthmocele-related postmenstrual spotting confirmed by sonography and diagnostic hysteroscopy between 2000 and 2017. Our new interventions included the following four steps: (1) make a resection gradient of the distal edge of the isthmocele from the ape of the isthmocele down to the cervical outer orifice; (2) resect the distal and proximal niches of the isthmocele; (3) electrocauterize the distal and proximal sides (not only the niche bottom) of the small cave on the scar side of the isthmocele; (4) manage the isthmocele until it is largely connected to the cavity. In our results, all patients underwent extensive hysteroscopic repair of newly hysteroscopic isthmoplasty without any intra- or postoperative complications. After final hysteroscopic repair modification, prolonged menstrual spotting was significantly decreased in 98.2% (53/54) of the patients, and the total number of bleeding days per menstrual cycle significantly decreased from a mean of 15.38 ± 3.3 days to 6.4 ± 1.9 days postoperatively (p < 0.001). Our four-step hysteroscopic technique successfully resolved prolonged menstrual spotting in over 90% of the patients, exceeding the resolution rates of 60-85% achieved with other hysteroscopic techniques used to treat symptomatic isthmocele. No patients experience recurrence after long-term follow up. Four simple steps led to a significant improvement in bleeding status.

Сохранение геологического материала и история открытий карстовых образований Печоро-Североуральского спелеологического района и прилегающих территорий

The paper describes the history of discovery and study of karst formations of the European North of Russia. More than 100 karst formations have been identified. The main periods in the history of exploration of caves and grottoes of the Pechora Urals are reflected. The first caves descriptions which were made by travellers and scientists in the 18th19th centuries are given. During that period the most famous caves were Uninskaya and Kaninskaya caves. The main karst formations were discovered and described at the beginning of the 20th century. Geologist V.N. Mamontov discovered 4 caves on the Pervokamennaya River. Systematic geological studies by V.A. Varsanofyeva in the Northern Urals allowed her to discover small karst formations in the upper reaches of the Pechora on the Ilych and Unya rivers. In 1960, B.I. Guslitzer discovered the largest cave in the Northern Urals — the Medvezhya Cave. Promising and little-studied areas of karst are the Bolshezemelskaya Tundra, the Polar and Nether-Polar Urals, Pai-Hoi and Timan. Only a few small caves and grottoes are known on these territories. Most of the karst is located in specially protected areas. The caves are unique paleontological monuments of nature. The funds of the A.A. Chernov Geological Museum of the Institute of Geology contain 12 monographic collections of paleofaunistic material with a volume of more than 30 thousand storage units. The remains of vertebrate caves consist of bones of mammoth fauna and small mammals.

Plausible Detection of Feasible Cave Networks Beneath Impact Melt Pits on the Moon Using the Grail Mission

In the future, when humans build their bases on terrestrial planets and their moons, caves will be the safest place for inhabitation. Large holes, believed to be cave entrances, have been discovered on the Moon, along with small features called “impact melt pits.” In the Gravity Recovery and Interior Laboratory (GRAIL) gravity model, which is expressed in spherical harmonics (SH), it is difficult to express the gravity anomaly created by a small empty space below the surface. Nevertheless, we propose that a cave network, akin to an anthill, exists under the impact melt pits discovered on the Moon. This is because we think it is natural to apply a network created by Earth’s small caves to the Moon. We obtained accurate Bouguer gravity measurements by calculating regional crustal density using localized admittance of the study area and detected weak gravity (mass deficit) information. By increasing the degrees and order of SH at regular intervals, we estimated the change in gravity at a specific position at high degrees and order, thereby extracting shallow depth information. To validate our method, we compared our results with those of existing studies that analyzed the previously known Marius Hills Hole (MHH) area. The analysis of seven regions in our study area revealed a mass deficit in some impact melt pits in four lunar regions (Copernicus, King, Stevinus, and Tycho). We propose that there is a cave network in this region, indicated by the gravitation reduction in the impact melt pits region. Our results can be useful for the selection of landing sites for future in situ explorations of lunar caves.

Facile Solution Process of VO2 Film with Mesh Morphology for Enhanced Thermochromic Performance.

The fabrication and applications of VO2 film continue to be of considerable interest due to their good thermochromic performance for smart windows. However, low visible transmittance (Tlum) and solar modulation efficiency (∆Tsol) impede the application of VO2 film, and they are difficult to improve simultaneously. Here, a facile zinc solution process was employed to control the surface structure of dense VO2 film and the processed VO2 film showed enhanced visible transmittance and solar modulation efficiency, which were increased by 7.5% and 9.5%, respectively, compared with unprocessed VO2 film. This process facilitated the growth of layered basic zinc acetate (LBZA) nanosheets to form mesh morphology on the surface of VO2 film, where LBZA nanosheets enhance the visible transmittance as an anti-reflection film. The mesh morphology also strengthened the solar modulation efficiency with small caves between nanosheets by multiplying the times of reflection. By increasing the zinc concentration from 0.05 mol/L to 0.20 mol/L, there were more LBZA nanosheets on the surface of the VO2 film, leading to an increase in the solar/near-infrared modulation efficiency. Therefore, this work revealed the relationship between the solution process, surface structure, and optical properties, and thus can provide a new method to prepare VO2 composite film with desirable performance for applications in smart windows.

Detection of Shallow Cavities Using 3D Resistivity Technique in a Small Site Near Haditha City, Western Iraq

Iraqi western desert is characterized by a widespread karst phenomenon and caves. Euphrates formation (Lower Miocene) includes enormous sinkholes and cavities within carbonate rocks that usually cause severe damages to any kind of engineering facilities built over it. 3D resistivity imaging techniques were used in detecting this kind of cavities in complicated lithology. The 3D view was fulfilled by collating seven 2D imaging lines. The 2D imaging survey was carried out by Dipole-dipole array with (n) factor and electrode spacing (a) of 6 and 2m respectively. The horizontal slices of the 3D models give a good subsurface picture. There are many caves in all directions (x, y, z). They reveal many small caves near the surface. These caves are clearly shown as points with highly variable resistivity values in slices of depths 0.80 m, 1.72 m, 2.78 m, and 3.99 m. The comparison between standard Least-square and robust constrain methods appeared that the inverse model produced by the robust constrain method has sharper and straighter boundaries. The results of both the two-dimensional and the three-dimensional resistive imaging models deal with almost the same spread of subsurface caves in the study area and show a high amount in number, especially in the upper part, white in color oolitic limestone, the second member of Euphrates Formation, of 3.8-8m depth. 2D and 3D resistivity imaging values have Standard Roof-mean square (RMS) error for large inverted models, this confirms that the study area is of high inhomogeneity. This heterogeneity resulted in a large variation in the resistivity of the rock component in addition to the large spread of caves near the surface.

First Data on Non-occlusal Surface Incisor Microwear of Cave Bears from the Urals

The microwear of the non-occlusal surface of incisors (I1, I2) of the small cave bear (Ursus ex gr. savini-rossicus) and Ural cave bear (Ursus kanivetz) from the Pleistocene of the Middle and South Urals is analyzed and compared. Qualitative characteristics of incisor microwear have been shown to be different in these species. In the small cave bear, coarser lesions on the non-occlusal surface of the incisors are observed. Considering the specificity of microwear of non-occlusal tooth surfaces, the data obtained suggest differences in trophic specialization of the species. studied.