Color patterns in white‐beaked dolphins (Lagenorhynchus albirostris) from Iceland

Few studies have examined the natural complex pigmentation patterns of white‐beaked dolphins. From 2002 to 2014, whale‐watching trips in Iceland provided a platform of opportunity to collect a large body of photographs of free‐ranging individuals from a single area of distribution for this species. Based on 823 images, 571 individuals showing one or more color components were identified, and assigned to the following four age classes: adults (n = 437), juveniles (n = 109), calves (n = 14), and neonates (n = 11). A total of 26 color components were observed and described: seven terms previously applied to white‐beaked dolphins, 12 previously applied to other dolphin species, and seven newly defined terms. Results showed that each age class could be positively identified by differences in specific color components, some of which were exclusive. Therefore, color patterns may prove useful in estimating maturity in free‐ranging white‐beaked dolphins. This tool could be further refined through assessment of a wide sample of freshly stranded specimens of known sex and age, which could reveal new age class‐specific components, as well as sexually dimorphic characteristics not seen here. Geographic variation should be investigated by comparing image data sets and stranded animals from different parts of the North Atlantic.     

Clinical assessment and postrelease monitoring of 11 mass stranded dolphins on Cape Cod,Massachusetts

The health, postrelease movements, and behavior of mass stranded Atlantic white‐sided dolphins (Lagenorhynchus acutus) and short‐beaked common dolphins (Delphinus delphis) from Cape Cod, Massachusetts, were evaluated. Health was assessed through physical examination and blood analysis. Eleven dolphins (eight white‐sided dolphins and three common dolphins) were relocated, outfitted with satellite transmitters, and released during seven mass stranding events. Five transmitters recorded only location, and six also included a time‐depth recorder. Transmission duration ranged from 8 h to 218 d, with a mean of 117 d (median = 118 d, SD = 82 d), after release. All dolphins demonstrated extensive movement throughout the Gulf of Maine. The distribution of tagged dolphins was considered normal based on comparisons with published data for these species. Excluding the dolphin that transmitted for only 8 h, mean minimum speeds for individual dolphins ranged from 3.4 to 6.6 km/h; overall mean for all dolphins was 5.4 km/h (SD = 0.9 km/h). The five dolphins with time‐depth recorders had mean dive depths of 8.6–40.3 m and mean dive durations of 46–296 s. Hematologic and biochemical data revealed only minor abnormalities. Data suggest that at least 10 of the 11 dolphins were likely successfully reintroduced into the wild.     

Preliminary evidence for a two‐for‐one deal: Wetland restoration for a threatened frog may benefit a threatened bat

Habitat restoration is an integral feature of wildlife conservation. However, funding and opportunities for habitat restoration are limited, and therefore, it is useful for targeted restoration to provide positive outcomes for non‐target species. Here, we investigate the possibility of habitat creation and management benefitting two threatened wetland specialists: the Green and Golden Bell Frog (Litoria aurea) and the Large‐footed Myotis (Myotis macropus). This study involved two components: (i) assessing co‐occurrence patterns of these species in a wetland complex created for the Green and Golden Bell Frog (n = 9) using counts, and (ii) comparing foraging activity of Large‐footed Myotis in wetlands with low and high aquatic vegetation (n = 6 and 7, respectively) using echolocation metres. Since Large‐footed Myotis possesses a unique foraging behaviour of trawling for aquatic prey, we hypothesised that foraging activity of this species would be higher in wetlands with low aquatic vegetation coverage. Additionally, we provide observations of its potential prey items. We identified one created wetland where both species were found in relatively high numbers, and this wetland had a permanent hydrology, was free of the introduced fish Gambusia (Gambusia holbrooki) and had low aquatic vegetation coverage. We also found that Myotis feeding activity was significantly higher in low aquatic vegetation coverage wetlands (x? = 65.72 ± 27.56 SE) compared to high (x? = 0.33 ± 0.33 SE, P = 0.0000). Although this is a preliminary study, it seems likely that Green and Golden Bell Frog and Large‐footed Myotis would gain mutual benefit from wetlands that are constructed to be permanent, that are Gambusia free, low in aquatic vegetation coverage, and are located in close to suitable roosting habitat for Large‐footed Myotis. We encourage adaptive aquatic vegetation removal for Green and Golden Bell frog as this may have benefits for Large‐footed Myotis. The evidence suggests that the former may be a suitable umbrella species for the latter.     

Superbanone,A New 2‐Aryl‐3‐benzofuranone and Other Bioactive Constituents from the Tube Roots of Butea superba

Phytochemical investigation from the tube roots of Butea superba, led to the isolation and identification of a new 2‐aryl‐3‐benzofuranone named superbanone ( 1 ), one benzoin, 2‐hydroxy‐1‐(2‐hydroxy‐4‐methoxyphenyl)‐2‐(4‐methoxyphenyl)ethanone ( 2 ), eight pterocarpans ( 3  –  10 ), and eleven isoflavonoids ( 11  –  21 ). Compound 2 was identified for the first time as a natural product. The structure of the isolated compounds was elucidated using spectroscopic methods, mainly 1D‐ and 2D‐NMR. The isolated compounds and their derivatives were evaluated for α‐glucosidase inhibitory and antimalarial activities. Compounds 3 , 7 , 8 , and 11 showed promising α‐glucosidase inhibitory activity (IC₅₀ = 13.71 ± 0.54, 23.54 ± 0.75, 28.83 ± 1.02, and 12.35 ± 0.36 μm , respectively). Compounds 3 and 11 were twofold less active than the standard drug acarbose (IC₅₀ = 6.54 ± 0.04 μm ). None of the tested compounds was found to be active against Plasmodium falciparum strain 94. On the basis of biological activity results, structure–activity relationships are discussed.     

Unexpected cryptic species diversity in the widespread coral Seriatopora hystrix masks spatial‐genetic patterns of connectivity

Mounting evidence of cryptic species in a wide range of taxa highlights the need for careful analyses of population genetic data sets to unravel within‐species diversity from potential interspecies relationships. Here, we use microsatellite loci and hierarchical clustering analysis to investigate cryptic diversity in sympatric and allopatric (separated by 450 km) populations of the widespread coral Seriatopora hystrix on the Great Barrier Reef. Structure analyses delimited unique genetic clusters that were confirmed by phylogenetic and extensive population‐level analyses. Each of four sympatric yet distinct genetic clusters detected within S. hystrix demonstrated greater genetic cohesion across regional scales than between genetic clusters within regions (<10 km). Moreover, the magnitude of genetic differentiation between different clusters (>0.620 G”_ST) was similar to the difference between S. hystrix clusters and the congener S. caliendrum (mean G”_ST 0.720). Multiple lines of evidence, including differences in habitat specificity, mitochondrial identity, Symbiodinium associations and morphology, corroborate the nuclear genetic evidence that these distinct clusters constitute different species. Hierarchical clustering analysis combined with more traditional population genetic methods provides a powerful approach for delimiting species and should be regularly applied to ensure that ecological and evolutionary patterns interpreted for single species are not confounded by the presence of cryptic species.     

Spatial dynamics and mixing of bluefin tuna in the Atlantic Ocean and Mediterranean Sea revealed using next‐generation sequencing

The Atlantic bluefin tuna is a highly migratory species emblematic of the challenges associated with shared fisheries management. In an effort to resolve the species’ stock dynamics, a genomewide search for spatially informative single nucleotide polymorphisms (SNPs) was undertaken, by way of sequencing reduced representation libraries. An allele frequency approach to SNP discovery was used, combining the data of 555 larvae and young‐of‐the‐year (LYOY) into pools representing major geographical areas and mapping against a newly assembled genomic reference. From a set of 184,895 candidate loci, 384 were selected for validation using 167 LYOY. A highly discriminatory genotyping panel of 95 SNPs was ultimately developed by selecting loci with the most pronounced differences between western Atlantic and Mediterranean Sea LYOY. The panel was evaluated by genotyping a different set of LYOY (n = 326), and from these, 77.8% and 82.1% were correctly assigned to western Atlantic and Mediterranean Sea origins, respectively. The panel revealed temporally persistent differentiation among LYOY from the western Atlantic and Mediterranean Sea (F_ST = 0.008, p = .034). The composition of six mixed feeding aggregations in the Atlantic Ocean and Mediterranean Sea was characterized using genotypes from medium (n = 184) and large (n = 48) adults, applying population assignment and mixture analyses. The results provide evidence of persistent population structuring across broad geographic areas and extensive mixing in the Atlantic Ocean, particularly in the mid‐Atlantic Bight and Gulf of St. Lawrence. The genomic reference and genotyping tools presented here constitute novel resources useful for future research and conservation efforts.     

How far bowalization affects phytodiversity,life forms and plant morphology in Sub‐humid tropic in West Africa

Bowal or ferricrete, the final of land degradation, occurred only in tropical region. This study aimed at assessing the effects of bowalization on phytodiversity, life forms and morphological response of plant species using Combretum nigricans Leprieur ex Guill. & Perr. as a case study. Morphological parameters (height, number of stems, number of branches, diameter at breast height and crown diameter) of C. nigricans were determined in the sub‐humid zone of Benin. Plant communities were determined according to Multi‐Response Permutation Procedures analysis. Plant communities were more diversified on sand‐clay and concretion soils (control) compared with those described on bowal. C. nigricans developed more stems (3.6 ± 1.4 stems vs. 1.3 ± 0.4 stems), more branches (5.9 ± 2.4 branches vs. 3.2 ± 0.6 branches) and large crown diameter (5 ± 1.48 m vs. 3.4 ± 1.2 m) on bowal than on sand‐clay soil. The best adapted life forms on bowal were therophytes. Bowalization induced loss of phytodiversity, changes in species life forms and provoked local adaptation of tree species.     

Evaluation of body mass index as a prognostic indicator from two rough‐toothed dolphin (Steno bredanensis) mass strandings in Florida

Rough‐toothed dolphins (Steno bredanensis) are a common mass stranding species in Florida. These large stranding events typically include a small number of sick or injured individuals and a much larger number of healthy individuals, making rapid triage essential. Little data exist on rehabilitation outcomes, and historically, successful outcomes are limited. Furthermore, very little data exist on the feeding habits and dietary needs of this species. This study compared morphology and body mass index (BMI) in two rough‐toothed dolphin mass stranding events in Florida: August 2004 (n = 36) and March 2005 (n = 32). The two groups were significantly different in morphologic measurements, with age and gender‐adjusted intake BMI significantly (p < .01) different (2004 = 0.34 ± 0.02; 2005 = 0.41 ± 0.02) between groups. Ten animals from 2005 had weights tracked throughout the rehabilitation process and demonstrated an initial drop in BMI followed by an increase and a plateau prior to release. When comparing initial BMI by stranding outcome, individuals that were rehabilitated and released had a significantly (p = .03) higher BMI than individuals who were euthanized. However, there was no difference between dolphins that died of natural causes (p = .56) and animals successfully rehabilitated. Analysis of BMI can be a useful marker in triage during a stranding, when resources are limited to identify individuals most likely to survive, as well as in determining the appropriate body condition for release. The data reported here can provide guidance on evaluating the nutritive status on this uncommon species that would otherwise be difficult to obtain among wild populations.     

Genetic diversity of Chinese cattle revealed by Y‐SNP and Y‐STR markers

With its vast territory and complex natural environment, China boasts rich cattle genetic resources. To gain the further insight into the genetic diversity and paternal origins of Chinese cattle, we analyzed the polymorphism of Y‐SNPs (UTY19 and ZFY10) and Y‐STRs (INRA189 and BM861) in 34 Chinese cattle breeds/populations, including 606 males representative of 24 cattle breeds/populations collected in this study as well as previously published data for 302 bulls. Combined genotypic data identified 14 Y‐chromosome haplotypes that represented three haplogroups. Y2‐104‐158 and Y2‐102‐158 were the most common taurine haplotypes detected mainly in northern and central China, whereas the indicine haplotype Y3‐88‐156 predominates in southern China. Haplotypes Y2‐108‐158, Y2‐110‐158, Y2‐112‐158 and Y3‐92‐156 were private to Chinese cattle. The population structure revealed by multidimensional scaling analysis differentiated Tibetan cattle from the other three groups of cattle. Analysis of molecular variance showed that the majority of the genetic variation was explained by the genetic differences among groups. Overall, our study indicates that Chinese cattle retain high paternal diversity (H = 0.607 ± 0.016) and probably much of the original lineages that derived from the domestication center in the Near East without strong admixture from commercial cattle carrying Y1 haplotypes.     

Clonal Diversity and Fine‐scale Genetic Structure in a High Andean Treeline Population

Clonal propagation becomes more abundant with increasing altitudes as environmental conditions worsen. To date, little attention has been paid to the way in which clonal propagation affects genetic diversity and the fine‐scale spatial genetic structure (FSGS) of clonal alpine trees. An AFLP study was undertaken to quantify the clonal and genetic diversity and FSGS of the vulnerable treeline species Polylepis reticulata in Ecuador. We successfully genotyped 32 and 75 ramets within 4 m × 100 m (coarse scale) and 4 m × 4 m (fine scale) transects of one population, respectively. Higher genotypic diversity was detected at the coarse scale than at the fine scale, while lower genetic diversity was detected for P. reticulata than other Polylepis spp. at both scales. Significantly stronger FSGS was detected at the ramet level than the genet level for P. reticulata within a spatial distance of 3 m. The studied P. reticulata population showed pronounced FSGS (Sp = 0.012 at the genet level, a statistic reflecting declining pairwise kinship with distance) revealed restricted gene dispersal, which implies restricted seed dispersal for this population, assuming pollen flow is as extensive as that described for other wind‐pollinated tree species. Our results revealed that clonal diversity is a function of both sample size and the spatial scale of the sampling area. The findings highlights that clonal propagation has affected FSGS within a spatial distance of 3 m for this species.     

Fine‐scale population structure of Collichtys lucidus populations inferred from microsatellite markers

The spinyhead croaker Collichthys lucidus (Richardson) is a small sciaenid species distributed along the inshore waters of northwestern Pacific Ocean, and now has been listed as Key Protected Commercial Sources of Aquatic Animals and Plants in China. To delineate stock boundaries and inform conservation policy for its management, samples were collected from eight locations across the Chinese coastal waters and analyzed at nine microsatellite loci. C. lucidus populations showed low genetic diversity (expected heterozygosity = 0.445–0.542; observed heterozygosity = 0.392–0.539; Polymorphism Information Content = 0.268–0.684). Strong genetic fdifferentiation (F_st = 0.065–0.510, all significant after Bonferroni correction) among all populations and high levels of self‐recruitment (89.2%–91.5%) were observed, which suggested limited genetic exchange for this species. Clustering results of discriminant analysis of principal components and STRUCTURE found strong support for obvious genetic clusters (populations FZ, XM and SZ vs. populations SH, YRE, ZS, WZ and ND). The results of the present study not only supported the phylogeographic pattern of north‐south differentiation, but also suggested that C. lucidus populations may be predominantly sustained by self‐replenishment rather than by recruitment from distant populations.     

Paedomorphosis in two small species of toothed whales (Odontoceti): how and why?

To evaluate and assess the ontogenetic background for paedomorphosis in phocoenids, samples of 144 harbour porpoises, 81 white‐beaked dolphins, and 130 Commerson's dolphins were compared in terms of the development of epiphyseal fusion, cranial suture fusion, and ontogeny of cranial shape. Harbour porpoises and Commerson's dolphins terminated growth and development of all investigated traits sooner than white‐beaked dolphins, leading to lesser degrees of fusion of skeletal elements and less postnatal allometric development. The latter occurred even though shape in the two paedomorphic species developed at twice the rate relative to the size of white‐beaked dolphins. These observations imply that progenetic evolution has occurred convergently in phocoenid and Cephalorhynchus ancestors. The truncated ontogenies allow sexual maturity to be attained earlier and provide a greater reproductive potential. Both species inhabit similar temperate productive habitats and, hence, ecological factors are proposed to have supplied the selection pressures leading to progenesis. Constant prey availability must be a prerequisite for the observed phenomena because frequent food‐intake is necessitated by the limited capacity for energy storage and high heat‐loss entailed by the resulting small body sizes. Progenesis has rarely been proposed in mammal species. This may reflect rarity or that mammalian expressions of progenesis are less obvious. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 278–295.     

Complex effects of mammalian grazing on extramatrical mycelial biomass in the Scandes forest‐tundra ecotone

Mycorrhizal associations are widespread in high‐latitude ecosystems and are potentially of great importance for global carbon dynamics. Although large herbivores play a key part in shaping subarctic plant communities, their impact on mycorrhizal dynamics is largely unknown. We measured extramatrical mycelial (EMM) biomass during one growing season in 16‐year‐old herbivore exclosures and unenclosed control plots (ambient), at three mountain birch forests and two shrub heath sites, in the Scandes forest‐tundra ecotone. We also used high‐throughput amplicon sequencing for taxonomic identification to investigate differences in fungal species composition. At the birch forest sites, EMM biomass was significantly higher in exclosures (1.36 ± 0.43 g C/m²) than in ambient conditions (0.66 ± 0.17 g C/m²) and was positively influenced by soil thawing degree‐days. At the shrub heath sites, there was no significant effect on EMM biomass (exclosures: 0.72 ± 0.09 g C/m²; ambient plots: 1.43 ± 0.94). However, EMM biomass was negatively related to Betula nana abundance, which was greater in exclosures, suggesting that grazing affected EMM biomass positively. We found no significant treatment effects on fungal diversity but the most abundant ectomycorrhizal lineage/cortinarius, showed a near‐significant positive effect of herbivore exclusion (p = .08), indicating that herbivory also affects fungal community composition. These results suggest that herbivory can influence fungal biomass in highly context‐dependent ways in subarctic ecosystems. Considering the importance of root‐associated fungi for ecosystem carbon balance, these findings could have far‐reaching implications.     

High site fidelity and restricted ranging patterns in southern Australian bottlenose dolphins

Information on site fidelity and ranging patterns of wild animals is critical to understand how they use their environment and guide conservation and management strategies. Delphinids show a wide variety of site fidelity and ranging patterns. Between September 2013 and October 2015, we used boat‐based surveys, photographic identification, biopsy sampling, clustering analysis, and geographic information systems to determine the site‐fidelity patterns and representative ranges of southern Australian bottlenose dolphins (Tursiops cf. australis) inhabiting the inner area of Coffin Bay, a highly productive inverse estuary located within Thorny Passage Marine Park, South Australia. Agglomerative hierarchical clustering (AHC) of individuals’ site‐fidelity index and sighting rates indicated that the majority of dolphins within the inner area of Coffin Bay are “regular residents” (n = 125), followed by “occasional residents” (n = 28), and “occasional visitors” (n = 26). The low standard distance deviation indicated that resident dolphins remained close to their main center of use (range = 0.7–4.7 km, X ± SD = 2.3 ± 0.9 km). Representative ranges of resident dolphins were small (range = 3.9–33.5 km², X ± SD = 15.2 ± 6.8 km²), with no significant differences between males and females (Kruskal–Wallis, χ² = 0.426, p = .808). The representative range of 56% of the resident dolphins was restricted to a particular bay within the study area. The strong site fidelity and restricted ranging patterns among individuals could be linked to the high population density of this species in the inner area of Coffin Bay, coupled with differences in social structure and feeding habits. Our results emphasize the importance of productive habitats as a major factor driving site fidelity and restricted movement patterns in highly mobile marine mammals and the high conservation value of the inner area of Coffin Bay for southern Australian bottlenose dolphins.     

Isotopic niche differs between seal and fish‐eating killer whales (Orcinus orca) in northern Norway

Ecological diversity has been reported for killer whales (Orcinus orca) throughout the North Atlantic but patterns of prey specialization have remained poorly understood. We quantify interindividual dietary variations in killer whales (n = 38) sampled throughout the year in 2017–2018 in northern Norway using stable isotopic nitrogen (δ¹⁵N: ¹⁵N/¹⁴N) and carbon (δ¹³C: ¹³C/¹²C) ratios. A Gaussian mixture model assigned sampled individuals to three differentiated clusters, characterized by disparate nonoverlapping isotopic niches, that were consistent with predatory field observations: seal‐eaters, herring‐eaters, and lumpfish‐eaters. Seal‐eaters showed higher δ¹⁵N values (mean ± SD: 12.6 ± 0.3‰, range = 12.3–13.2‰, n = 10) compared to herring‐eaters (mean ± SD: 11.7 ± 0.2‰, range = 11.4–11.9‰, n = 19) and lumpfish‐eaters (mean ± SD: 11.6 ± 0.2‰, range = 11.3–11.9, n = 9). Elevated δ¹⁵N values for seal‐eaters, regardless of sampling season, confirmed feeding at high trophic levels throughout the year. However, a wide isotopic niche and low measured δ¹⁵N values in the seal‐eaters, compared to that of whales that would eat solely seals (δ_N‐measured = 12.6 vs. δ_N‐expected = 15.5), indicated a diverse diet that includes both fish and mammal prey. A narrow niche for killer whales sampled at herring and lumpfish seasonal grounds supported seasonal prey specialization reflective of local peaks in prey abundance for the two fish‐eating groups. Our results, thus, show differences in prey specialization within this killer whale population in Norway and that the episodic observations of killer whales feeding on prey other than fish are a consistent behavior, as reflected in different isotopic niches between seal and fish‐eating individuals.     

Temperature sensitivity of biomass‐specific microbial exo‐enzyme activities and CO2 efflux is resistant to change across short‐ and long‐term timescales

Accurate representation of temperature sensitivity (Q₁₀) of soil microbial activity across time is critical for projecting soil CO₂ efflux. As microorganisms mediate soil carbon (C) loss via exo‐enzyme activity and respiration, we explore temperature sensitivities of microbial exo‐enzyme activity and respiratory CO₂ loss across time and assess mechanisms associated with these potential changes in microbial temperature responses. We collected soils along a latitudinal boreal forest transect with different temperature regimes (long‐term timescale) and exposed these soils to laboratory temperature manipulations at 5, 15, and 25°C for 84 days (short‐term timescale). We quantified temperature sensitivity of microbial activity per g soil and per g microbial biomass at days 9, 34, 55, and 84, and determined bacterial and fungal community structure before the incubation and at days 9 and 84. All biomass‐specific rates exhibited temperature sensitivities resistant to change across short‐ and long‐term timescales (mean Q₁₀ = 2.77 ± 0.25, 2.63 ± 0.26, 1.78 ± 0.26, 2.27 ± 0.25, 3.28 ± 0.44, 2.89 ± 0.55 for β‐glucosidase, N‐acetyl‐β‐d ‐glucosaminidase, leucine amino peptidase, acid phosphatase, cellobiohydrolase, and CO₂ efflux, respectively). In contrast, temperature sensitivity of soil mass‐specific rates exhibited either resilience (the Q₁₀ value changed and returned to the original value over time) or resistance to change. Regardless of the microbial flux responses, bacterial and fungal community structure was susceptible to change with temperature, significantly differing with short‐ and long‐term exposure to different temperature regimes. Our results highlight that temperature responses of microbial resource allocation to exo‐enzyme production and associated respiratory CO₂ loss per unit biomass can remain invariant across time, and thus, that vulnerability of soil organic C stocks to rising temperatures may persist in the long term. Furthermore, resistant temperature sensitivities of biomass‐specific rates in spite of different community structures imply decoupling of community constituents and the temperature responses of soil microbial activities.     

Noninvasive individual and species identification of jaguars (Panthera onca), pumas (Puma concolor) and ocelots (Leopardus pardalis) in Belize,Central America using cross‐species microsatellites and faecal DNA

There is a great need to develop efficient, noninvasive genetic sampling methods to study wild populations of multiple, co‐occurring, threatened felids. This is especially important for molecular scatology studies occurring in challenging tropical environments where DNA degrades quickly and the quality of faecal samples varies greatly. We optimized 14 polymorphic microsatellite loci for jaguars (Panthera onca), pumas (Puma concolor) and ocelots (Leopardus pardalis) and assessed their utility for cross‐species amplification. Additionally, we tested their reliability for species and individual identification using DNA from faeces of wild felids detected by a scat detector dog across Belize in Central America. All microsatellite loci were successfully amplified in the three target species, were polymorphic with average expected heterozygosities of H_E = 0.60 ± 0.18 (SD) for jaguars, H_E = 0.65 ± 0.21 (SD) for pumas and H_E = 0.70 ± 0.13 (SD) for ocelots and had an overall PCR amplification success of 61%. We used this nuclear DNA primer set to successfully identify species and individuals from 49% of 1053 field‐collected scat samples. This set of optimized microsatellite multiplexes represents a powerful tool for future efforts to conduct noninvasive studies on multiple, wild Neotropical felids.     

The effect of terrain and female density on survival of neonatal white‐tailed deer and mule deer fawns

Juvenile survival is a highly variable life‐history trait that is critical to population growth. Antipredator tactics, including an animal's use of its physical and social environment, are critical to juvenile survival. Here, we tested the hypothesis that habitat and social characteristics influence coyote (Canis latrans) predation on white‐tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) fawns in similar ways during the neonatal period. This would contrast to winter when the habitat and social characteristics that provide the most safety for each species differ. We monitored seven cohorts of white‐tailed deer and mule deer fawns at a grassland study site in Alberta, Canada. We used logistic regression and a model selection procedure to determine how habitat characteristics, climatic conditions, and female density influenced fawn survival during the first 8 weeks of life. Fawn survival improved after springs with productive vegetation (high integrated Normalized Difference Vegetation Index values). Fawns that used steeper terrain were more likely to survive. Fawns of both species had improved survival in years with higher densities of mule deer females, but not with higher densities of white‐tailed deer females, as predicted if they benefit from protection by mule deer. Our results suggest that topographical variation is a critical resource for neonates of many ungulate species, even species like white‐tailed deer that use more gentle terrain when older. Further, our results raise the possibility that neonatal white‐tailed fawns may benefit from associating with mule deer females, which may contribute to the expansion of white‐tailed deer into areas occupied by mule deer.