| 1. |
- Ahlén, Ingemar
(författare)
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Behavior of Scandinavian bats during migration and foraging at sea
- 2009
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Ingår i: Journal of Mammalogy. - 0022-2372 .- 1545-1542. ; 90, s. 1318-1323
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Tidskriftsartikel (refereegranskat)abstract
- We studied bats migrating and foraging over the sea by direct observations and automatic acoustic recording We recorded 11 species (of a community of 18 species) flying over the ocean up to 14 km from the shore. All bats used sonar during migration flights at sea, often with slightly lower frequencies and longer pulse intervals compared to those used over land. The altitude used for migration flight was most often < 10 m above sea level. Bats must use other sensory systems for long-distance navigation, but they probably use echoes from the water surface to orient to the immediate surroundings. Both migrant and resident bats foraged over the sea in areas with an abundance of insects in the air and crustaceans in the surface waters. When hunting insects near vertical objects such as lighthouses and wind turbines, bats rapidly changed altitude, for example, to forage around turbine blades. The findings illustrate why and how bats might be exposed to additional mortality by offshore wind power.
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| 2. |
- , Anonymous]
(författare)
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Editor's Choice
- 2018
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Ingår i: JOURNAL OF MAMMALOGY. - : Oxford University Press (OUP). - 0022-2372 .- 1545-1542. ; 99:2, s. 305-305
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Dalerum, Fredrik, et al.
(författare)
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Sex-specific dispersal patterns of wolverines : Insights from microsatellite markers
- 2007
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Ingår i: Journal of Mammalogy. - 0022-2372 .- 1545-1542. ; 88:3, s. 793-800
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Tidskriftsartikel (refereegranskat)abstract
- Dispersal of individuals can be defined as movement and settling outside the natal home range. Such dispersal is often sex-biased among vertebrates, and is generally expected to be male-biased in polygynous mammals. We used microsatellite markers scored on harvested wolverines (Gulo gulo) to test the prediction of male-biased dispersal in a population in the western Brooks Range, Alaska. Our analyses suggested a high rate of dispersal within the population, but provided no support for sex differences in dispersal tendencies across the sampled spatial scale. Previous studies have implied male-biased dispersal among wolverine populations on an interpopulation scale. We suggest 3, not exclusive, explanations to reconcile these differences: low power to detect sex biases in dispersal tendencies in this panmictic population; a scale-dependent component in dispersal tendencies, where males are overrepresented among interpopulation migrants; and lower reproductive success for dispersing females compared to more philopatric ones.
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| 4. |
- Elofsson, Rolf, et al.
(författare)
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A novel ultrastructure on the corneocyte surface of mammalian nasolabial skin.
- 2016
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Ingår i: Journal of Mammalogy. - : Oxford University Press (OUP). - 0022-2372 .- 1545-1542. ; 97:5, s. 1288-1294
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Tidskriftsartikel (refereegranskat)abstract
- In many mammals, the skin of the rhinarium includes a thick epidermal layer. The skin surface can be smooth but can also display a structure formed of domes, ridges, and polygonal areas: a dermatoglyphic or rhinoglyphic pattern. Each structure consists of an easily visible, large area of the epidermis. The abdominal epidermis may or may not have a dermatoglyphic pattern. The abdominal skin examined in our study had no pattern and was consequently unstructured and smooth. The ultrastructural surface pattern is formed in the granular and corneous regions of nasal epidermis by desmosome protrusions projecting into adjacent keratinocytes. Complete retraction of the keratinocyte protrusions with desmosomes in the abdominal epidermis creates an unstructured, smooth surface. The cornification process differs morphologically in nasolabial and abdominal skin. In this study, we report a novel structure in the nose skin. It is related only to the surface of a single corneocyte (keratinocyte) and consists of submicrometer pores or furrows, an ultrastructure pattern. It is not related to the rhinoglyphic pattern. The nose skin can thus have 2 unrelated patterns. This structure seems to be widespread among the Mammalia. We suggest the function of the structure is to keep the rhinarium evenly moist.
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| 5. |
- Garde, E., et al.
(författare)
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Life history parameters of narwhals (Monodon monoceros) from Greenland
- 2015
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Ingår i: Journal of Mammalogy. - : Oxford University Press (OUP). - 0022-2372 .- 1545-1542. ; 96:4, s. 866-879
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Tidskriftsartikel (refereegranskat)abstract
- Life history parameters for narwhals (Monodon monoceros) were estimated based on age estimates from aspartic acid racemization of eye lens nuclei. Eyes, reproductive organs, and measures of body lengths were collected from 282 narwhals in East and West Greenland in the years 1993, 2004, and 2007-2010. Age estimates were based on the racemization of L-aspartic acid to D-aspartic acid in the nucleus of the eye lens. The ratio of D- and L-enantiomers was measured using high-performance liquid chromatography. The age equation used, 420.32X - 24.02 center dot year where X is the D/L ratio, was determined from data from Garde et al. (2012). Asymptotic body length was estimated to be 405 +/- 5.8cm for females and 462 +/- 16.2cm for males from East Greenland, and 399 +/- 5.9cm for females and 456 +/- 6.9cm for males from West Greenland. Due to several indeterminant age class estimates, age at sexual maturity was subjectively assessed based on data from reproductive organs and was estimated to be 8-9 years for females and 12-20 years for males. Pregnancy rates for East and West Greenland were estimated to be 0.38-0.42 and 0.38, respectively. Maximum life span expectancy was found to be approximately 100 years. A population projection matrix was parameterized with the data on age structure and fertility rates. The annual rate of increase of narwhals in East Greenland was estimated to be 3.8% while narwhals in West Greenland had a rate of increase at 2.6%.
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| 6. |
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| 7. |
- Kjellander, Petter, et al.
(författare)
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Age-specific variation in male breeding success of a territorial ungulate species, the European roe deer
- 2009
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Ingår i: Journal of Mammalogy. - 0022-2372 .- 1545-1542. ; 90, s. 661-665
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Tidskriftsartikel (refereegranskat)abstract
- We investigated age-specific variation in male yearly breeding success (YBS) using genetic estimates obtained from 2 populations of a territorial ungulate, the European roe deer (Capreolus capreolus). YBS in both populations was markedly age-structured, with 3 distinct stages, supporting the dome-shaped pattern of variation commonly reported for age-dependent variation in life-history traits of ungulates. YBS was low at 2 years of age, peaked at 3-8 years of age, and tended to decline afterwards (senescence). Most males successfully reproduced for the 1st time at 3 years of age, which is well after their physiological maturity. The few successful young males (i.e., 2 year olds) were likely fast-growing individuals that could successfully hold a territory. The high variance in YBS and antler size for old males at Bogesund, Sweden, suggests that only some males of this age class are able to maintain large antlers and, hence, retain their territories.
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| 8. |
- Levi, Matana, et al.
(författare)
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Forage selection by Masai giraffes (Giraffa camelopardalis tippelskirchi) at multiple spatial scales
- 2022
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Ingår i: Journal of Mammalogy. - : Oxford University Press (OUP). - 0022-2372 .- 1545-1542. ; 103:3, s. 737-744
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Tidskriftsartikel (refereegranskat)abstract
- Management of rangelands requires knowledge of forage species that are preferred or avoided by wildlife and livestock. A recent expansion of woody vegetation into previously open grasslands in African savanna ecosystems negatively impacts many mammalian grazers. Nevertheless, the ecological role of bush encroacher plant species as food may present a benefit for browsing species. We quantified diet selection by Masai giraffes (Giraffa camelopardalis tippelskirchi) through foraging observations and vegetation sampling in the Tarangire Ecosystem of Tanzania, which includes large areas of a native shrub that livestock managers have classified as an encroacher species (Dichrostachys cinerea). We compared woody plant species used by giraffes for foraging with availability at two different spatial scales during the wet and dry seasons. Giraffes selected some woody plants such as Vachellia species while significantly avoiding others, both at the local and landscape scales. Giraffes preferred foraging on D. cinerea at both spatial scales and in both the wet and dry seasons. Management that has focused on benefiting grazing livestock by removal of encroaching species (e.g., D. cinerea) may have unintended consequences for wildlife, especially for browsing species like giraffes that feed extensively on the expanding bush species.
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| 9. |
- Mattisson, Jenny, et al.
(författare)
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Influence of intraguild interactions on resource use by wolverines and Eurasian lynx
- 2011
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Ingår i: Journal of Mammalogy. - 0022-2372 .- 1545-1542. ; 92, s. 1321-1330
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Tidskriftsartikel (refereegranskat)abstract
- It is important to the conservation and management of threatened or endangered carnivores to recognize interspecific interactions that can influence demography or behavior of the species involved. We studied the Eurasian lynx (Lynx lynx), an efficient predator, and wolverine (Gulo gulo), an opportunistic predator and scavenger, that coexist in the reindeer husbandry area in northern Sweden. Both species are major predators on semidomestic reindeer (Rangifer tarandus), but wolverines frequently scavenge ungulate carcasses. We examined the composition and use of food resources by wolverines and in particular the relative importance of lynx-killed reindeer in wolverine diet. We also examined the influence of wolverine scavenging on lynx kill rate. We found that 52% of carcasses visited by wolverines were lynx-killed reindeer, but only 11% were wolverine-killed reindeer. Of all wolverine locations at carcasses, 28% were on lynx-killed and 24% on wolverine-killed reindeer. Remaining locations were mainly on reindeer that died from accidents (23%) or were killed by unknown carnivores (9%). Lynx predation rate on reindeer was nine times higher than that of wolverines. Wolverines scavenged 68% of available lynx-killed reindeer, 29% of which were still being used by lynx at wolverine arrival. Still, wolverine scavenging had a limited influence on lynx kill rate. Time to next kill decreased only when the lynx kill was an adult reindeer in forest; however, most lynx-killed reindeer were found on tundra. Wolverines appear to benefit from coexistence with lynx through increased scavenging opportunities. We suspect that lynx presence reduces wolverine predation on reindeer due to increased scavenging opportunities. These results may have important implications for carnivore management in reindeer husbandry areas.
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| 10. |
- Persson, Jens
(författare)
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The wolverine's niche: linking reproductive chronology, caching, competition, and climate
- 2012
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Ingår i: Journal of Mammalogy. - 0022-2372 .- 1545-1542. ; 93, s. 634-644
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Tidskriftsartikel (refereegranskat)abstract
- Wolverines are demographically vulnerable and susceptible to impacts from climate change. Their distribution is correlated with persistent spring snow cover, but food-based explanations for this relationship have not been explored. We synthesize information on the timing of both wolverine reproductive events and food availability to improve our understanding of the behaviors, habitat features, and foods that influence reproductive success. Wolverine births are constrained to a brief period of the year and occur at an earlier date than other nonhibernating, northern carnivores. Our examination suggests that this timing is adaptive because it allows wolverines to take advantage of a cold, low-productivity niche by appending the scarce resources available during winter to the brief period of summer abundance. The wolverine’s bet-hedging reproductive strategy appears to require success in 2 stages. First, they must fuel lactation (February–April) with caches amassed over winter or acquisition of a sudden food bonanza (e.g., winter-killed ungulates); otherwise, early litter loss occurs. Next, they must fuel the majority of postweaning growth during the brief but relatively reliable summer period of resource abundance. The 1st stage is likely dependent on scavenged ungulate resources over most of the wolverine’s range, whereas the 2nd stage varies by region. In some regions the 2nd stage may continue to be focused on scavenging ungulate remains that have been provided by larger predators. In other regions the 2nd stage may be focused on predation by wolverines on small prey or neonatal ungulates. During all seasons and regions, caching in cold, structured microsites to inhibit competition with insects, bacteria, and other scavengers is likely a critical behavioral adaptation because total food resources are relatively limited within the wolverine’s niche. Habitat features that facilitate caching, e.g., boulders and low ambient temperatures, are likely important and could be related to the limits of distribution. This ‘‘refrigeration-zone’’ hypothesis represents a food-based explanation for the correlation between wolverine distribution and persistent spring snow cover. Understanding regional differences in foods that fuel reproduction and underlying causes to the limits of distribution could be important for maintaining wolverine populations in the future.
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