scholarly journals Migratory strategies of juvenile northern fur seals (Callorhinus ursinus): bridging the gap between pups and adults

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tonya Zeppelin ◽  
Noel Pelland ◽  
Jeremy Sterling ◽  
Brian Brost ◽  
Sharon Melin ◽  
...  
Keyword(s):  
Body Mass ◽  
Environmental Variability ◽  
North Pacific Ocean ◽  
Diving Behavior ◽  
Callorhinus Ursinus ◽  
Differential Migration ◽  
Breeding Sites ◽  
Demographic Groups ◽  
Migratory Strategies ◽  
Similar Body

Abstract In species exhibiting differential migration by sex and age, understanding what differences exist, and the adaptive reasons for these differences is critical for determining how demographic groups will respond to environmental variability and anthropogenic perturbations. We used satellite-telemetered movement and diving data to investigate differential migration and its ontogeny in a highly migratory North Pacific Ocean predator, the northern fur seal (Callorhinus ursinus; NFS), with a focus on understudied juvenile (1- to 2-year-old) animals. We instrumented 71 juvenile NFS in two years (2006–07 and 2007–08) at three major North American breeding sites and compared their migratory strategies with pups and adults. Although sexual dimorphism is strong in adult NFS, only weak differences in body mass between sexes were found in juveniles, which had similar body mass to pups (~3–4 months). However, unlike widely-dispersed pups, juvenile male and female NFS dispersed in different directions, and used different habitats characterized by distinct hydrography and prey assemblages during migration, similar to breeding adults. Juvenile diving behavior differed only modestly among habitats and between sexes, consistent with weak differences in body mass. Evidence of habitat sexual segregation by juvenile NFS contradicts previous hypotheses that physiological differences predominantly drive the ontogeny of differential migration.

At-sea behavior of juvenile male northern fur seals (Callorhinus ursinus)

2004 ◽  
Vol 82 (10) ◽  
pp. 1621-1637 ◽  
Author(s):  
J T Sterling ◽  
R R Ream
Keyword(s):  
Body Mass ◽  
Mass Gain ◽  
Callorhinus Ursinus ◽  
Juvenile Male ◽  
Deep Waters ◽  
Fur Seals ◽  
Straight Line ◽  
Northern Fur Seals ◽  
Straight Line Distance ◽  
Pribilof Islands

The at-sea behavior of juvenile male northern fur seals, Callorhinus ursinus (L., 1758), captured at two haul-out sites on St. Paul Island, Alaska, during the 1999 and 2000 breeding seasons (July–September) was studied. To compare at-sea locations, dive behavior, and changes in body mass, 31 juveniles between the estimated ages of 3–6 years were captured, instrumented, and released. Individuals behaved like central-place foragers by making trips to sea and returning to the Pribilof Islands. Trip durations ranged between 8.74 and 29.81 d, whereas distances from departure site ranged between 171.27 and 680.68 km (maximum straight-line distance). Differences in maximum straight-line distance traveled and trip duration were not observed when comparing years or departure site. Diving tended to reflect patterns associated with different bathymetric domains; shallow nighttime diving was common in ~3000 m deep waters, whereas deeper diving was generally observed in <200 m deep waters. Proportion of body mass gained over a single trip to sea averaged 27.8% (range 3%–65%, n = 19). Mass gain was similar between individuals that dove in shallow waters (over the continental shelf; 10.9 ± 1.8 kg (mean ± 1 SE), n = 11) versus individuals that dove in pelagic waters (8.5 ± 1.0 kg, n = 8). These results demonstrate that the at-sea behavior of juvenile males can extend farther from the Pribilof Islands when compared with previous reports of parturient female at-sea behavior, thus revealing important variation within this species.

scholarly journals Development and validation of anthropometric prediction equations for estimation of lean body mass and appendicular lean soft tissue in Indian men and women

2013 ◽  
Vol 115 (8) ◽  
pp. 1156-1162 ◽  
Author(s):  
Bharati Kulkarni ◽  
Hannah Kuper ◽  
Amy Taylor ◽  
Jonathan C. Wells ◽  
K. V. Radhakrishna ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Lean Body Mass ◽  
Body Mass ◽  
Prediction Models ◽  
Reference Method ◽  
Epidemiological Studies ◽  
Prediction Equations ◽  
Men And Women ◽  
Wide Range ◽  
Similar Body

Lean body mass (LBM) and muscle mass remain difficult to quantify in large epidemiological studies due to the unavailability of inexpensive methods. We therefore developed anthropometric prediction equations to estimate the LBM and appendicular lean soft tissue (ALST) using dual-energy X-ray absorptiometry (DXA) as a reference method. Healthy volunteers ( n = 2,220; 36% women; age 18-79 yr), representing a wide range of body mass index (14–44 kg/m2), participated in this study. Their LBM, including ALST, was assessed by DXA along with anthropometric measurements. The sample was divided into prediction (60%) and validation (40%) sets. In the prediction set, a number of prediction models were constructed using DXA-measured LBM and ALST estimates as dependent variables and a combination of anthropometric indices as independent variables. These equations were cross-validated in the validation set. Simple equations using age, height, and weight explained >90% variation in the LBM and ALST in both men and women. Additional variables (hip and limb circumferences and sum of skinfold thicknesses) increased the explained variation by 5–8% in the fully adjusted models predicting LBM and ALST. More complex equations using all of the above anthropometric variables could predict the DXA-measured LBM and ALST accurately, as indicated by low standard error of the estimate (LBM: 1.47 kg and 1.63 kg for men and women, respectively), as well as good agreement by Bland-Altman analyses (Bland JM, Altman D. Lancet 1: 307–310, 1986). These equations could be a valuable tool in large epidemiological studies assessing these body compartments in Indians and other population groups with similar body composition.

Environmental variability and fledging body mass of Common Guillemot Uria aalge chicks

2013 ◽  
Vol 160 (5) ◽  
pp. 1239-1248 ◽  
Author(s):  
Robert T. Barrett ◽  
Kjell Einar Erikstad
Keyword(s):  
Body Mass ◽  
Environmental Variability ◽  
Uria Aalge ◽  
Common Guillemot

scholarly journals Low effective mechanical advantage of giraffes’ limbs during walking reveals trade-off between limb length and locomotor performance

2021 ◽  
Author(s):  
Christopher Basu ◽  
John R. Hutchinson
Keyword(s):  
Body Mass ◽  
Inverse Dynamics ◽  
Limb Length ◽  
Segment Length ◽  
Mechanical Advantage ◽  
Walking Gait ◽  
Moment Arms ◽  
Athletic Ability ◽  
Close Relatives ◽  
Similar Body

AbstractGiraffes (Giraffa camelopardalis) possess specialised locomotor morphology, namely elongate and gracile distal limbs. Whilst this contributes to their overall height (and enhanced feeding behaviour), we propose that the combination of long limb segments and modest muscle lever arms results in low effective mechanical advantage (EMA, the ratio of in-lever to out-lever moment arms), when compared with other cursorial mammals. To test this, we used a combination of experimentally measured kinematics and ground rection forces (GRFs), musculoskeletal modelling, and inverse dynamics to calculate giraffe forelimb EMA during walking. Giraffes walk with an EMA of 0.34 (±0.05 S.D.), with no evident association with speed within their walking gait. Giraffe EMA was markedly below the expectations extrapolated from other mammals ranging from 0.03 – 297 kg, and provides further evidence that EMA plateaus or even diminishes in mammals exceeding horse size. We further tested the idea that limb segment length is a factor which determines EMA, by modelling the GRF and muscle moment arms in the extinct giraffid Sivatherium giganteum and the other extant giraffid Okapia johnstoni. Giraffa and Okapia shared similar EMA, despite a 4-6 fold difference in body mass (Okapia EMA = 0.38). In contrast Sivatherium, sharing a similar body mass to Giraffa, had greater EMA (0.59), which we propose reflects behavioural differences, such athletic performance. Our modelling approach suggests that limb length is a determinant of GRF moment arm magnitude, and that unless muscle moment arms scale isometrically with limb length, tall mammals are prone to low EMA.Significance StatementGiraffes are the tallest living animals - using their height to access food unavailable to their competitors. It is not clear how their specialized anatomy impacts their athletic ability. We made musculoskeletal models of the forelimbs from a giraffe and two close relatives, and used motion-capture and forceplate data to measure how efficient they are when walking in a straight line. A horse for example, uses just 1 unit of muscle force to oppose 1 unit of force on the ground. Giraffe limbs however are comparatively disadvantaged – their muscles must develop 3 units of force to oppose 1 unit of force at the ground. This explains why giraffes walk and run at relatively slow speeds.

scholarly journals From Mediterranean to Scandinavia—timing and body mass condition in four long distance migrants

Ornis Svecica ◽  
2015 ◽  
Vol 25 (1–2) ◽  
pp. 51-58
Author(s):  
Christos Barboutis ◽  
Leo Larsson ◽  
Åsa Steinholtz ◽  
Thord Fransson
Keyword(s):  
Body Mass ◽  
Arrival Time ◽  
Long Distance ◽  
Breeding Sites ◽  
Swedish Study ◽  
Collared Flycatcher ◽  
Stopover Sites ◽  
Early Arrival ◽  
Breeding Grounds ◽  
Pass Through

In spring, long-distance migrants are considered to adopt a time-minimizing strategy to promote early arrival at breeding sites. The phenology of spring migration was examined and compared between two insular stopover sites in Greece and Sweden for Icterine Warbler, Wood Warbler, Spotted Flycatcher and Collared Flycatcher. All of them migrate due north which means that some proportion of birds that pass through Greece are heading to Scandinavia. The Collared Flycatcher had the earliest and the Icterine Warbler the latest arrival time. The differences in median dates between Greece and Sweden were 3–4 weeks and the passages in Sweden were generally more condensed in time. The average overall speed estimates were very similar and varied between 129 and 137 km/d. In most of the species higher speed estimates were associated with years when birds arrived late in Greece. After crossing continental Europe birds arrive at the Swedish study site with significantly higher body masses compared to when they arrive in Greece and this might indicate a preparation for arriving at breeding grounds with some overload.

Predicting risk of decompression sickness in humans from outcomes in sheep

1999 ◽  
Vol 86 (6) ◽  
pp. 1920-1929 ◽  
Author(s):  
Robert Ball ◽  
Charles E. Lehner ◽  
Erich C. Parker
Keyword(s):  
Animal Model ◽  
Kinetic Parameters ◽  
Body Mass ◽  
Decompression Sickness ◽  
Compressed Air ◽  
Combined Model ◽  
Scaled Model ◽  
Log Likelihood ◽  
Practical Tool ◽  
Similar Body

In animals, the response to decompression scales as a power of species body mass. Consequently, decompression sickness (DCS) risk in humans should be well predicted from an animal model with a body mass comparable to humans. No-stop decompression outcomes in compressed air and nitrogen-oxygen dives with sheep ( n = 394 dives, 14.5% DCS) and humans ( n = 463 dives, 4.5% DCS) were used with linear-exponential, probabilistic modeling to test this hypothesis. Scaling the response parameters of this model between species (without accounting for body mass), while estimating tissue-compartment kinetic parameters from combined human and sheep data, predicts combined risk better, based on log likelihood, than do separate sheep and human models, a combined model without scaling, and a kinetic-scaled model. These findings provide a practical tool for estimating DCS risk in humans from outcomes in sheep, especially in decompression profiles too risky to test with humans. This model supports the hypothesis that species of similar body mass have similar DCS risk.

Diving behavior reduces genera richness of lice (Insecta, Phthiraptera) of mammals

2007 ◽  
Vol 52 (1) ◽  
Author(s):  
Bernadett Felső ◽  
Lajos Rózsa
Keyword(s):  
Species Richness ◽  
Body Mass ◽  
Comparative Approach ◽  
Diving Behavior ◽  
Taxonomic Richness ◽  
Entire Life ◽  
Confounding Variables ◽  
The Mean ◽  
The Difference ◽  
Aquatic Mammals

AbstractLice of mammals spend the entire life cycle in the host hair, thus, the microclimate found near the mammal skin is likely to influence the structure of louse communities. Here we use a comparative approach to examine the effect of mammals’ diving behavior on the taxonomic richness of their lice. We compared the mean genera richness of lice, and — as potential confounding variables — the mean species richness of host, and the mean body mass of host between diving clades and their non-diving sister clades. Louse genera richness was significantly lower in clades of aquatic mammals than on their non-diving sister clades. Host species richness was not significantly different between these clades. Body mass was significantly higher in clades of aquatic mammals, however, the direction of this difference cannot explain the difference in parasite taxonomic richness. This study suggests that mammals’ diving behavior can effectively shape their ectoparasite communities.

Sign in / Sign up

Export Citation Format

Share Document