Sexual dimorphism in sea lion pups: differential maternal investment, or sex-specific differences in energy allocation?

1996 ◽  
Vol 38 (1) ◽  
pp. 31-41 ◽  
Author(s):  
K. A. Ono ◽  
Daryl J. Boness
Keyword(s):  
Sexual Dimorphism ◽  
Maternal Investment ◽  
Energy Allocation ◽  
Sea Lion

Maternal strategies of the Australian sea lion (Neophoca cinerea) at Dangerous Reef, South Australia

2011 ◽  
Vol 59 (1) ◽  
pp. 54 ◽  
Author(s):  
Andrew D. Lowther ◽  
Simon D. Goldsworthy
Keyword(s):  
South Australia ◽  
Maternal Investment ◽  
Milk Lipid ◽  
Resource Exploitation ◽  
Sea Lion ◽  
Breeding Sites ◽  
Neophoca Cinerea ◽  
Australian Sea Lion ◽  
Spatial Differences ◽  
Pup Growth

Maternal strategies of otariid seals reflect the optimisation between resource exploitation and offspring provisioning driven across spatially separated foraging and nursing grounds. Intercolony variation in the expression of maternal strategies may represent temporal and spatial differences in resource availability, intraspecies competition or differences in life-history traits. The current study describes maternal strategies of the Australian sea lion at the largest breeding colony of the species (Dangerous Reef) and a comparative analysis was performed with data collected 16 years earlier at Seal Bay (Kangaroo Island). Significant differences in maternal strategies were characterised by lower milk lipid content (21.0 versus 28.9%), abbreviated periods onshore (0.93 versus 1.63 days) and slower pup growth rates (0.09–0.12 kg day–1) at Dangerous Reef. These data suggest flexibility in the expression of maternal investment between breeding sites and support the hypothesis of localised adaptation

BEHAVIORAL AND PHYSIOLOGICAL MEASUREMENTS OF MATERNAL INVESTMENT IN THE STELLER SEA LION, EUMETOPIAS JUBATUS

1988 ◽  
Vol 4 (1) ◽  
pp. 44-58 ◽  
Author(s):  
Lesley V. Higgins ◽  
Daniel P. Costa ◽  
Anthony C. Huntley ◽  
Burney J. Boeuf
Keyword(s):  
Maternal Investment ◽  
Steller Sea Lion ◽  
Eumetopias Jubatus ◽  
Sea Lion

Sexual dimorphism in cordylid lizards: a case study of the Drakensberg crag lizard, Pseudocordylus melanotus

1993 ◽  
Vol 71 (9) ◽  
pp. 1715-1723 ◽  
Author(s):  
P. le F. N. Mouton ◽  
J. H. van Wyk
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Activity ◽  
Energy Allocation ◽  
Head Size ◽  
Adult Males ◽  
Altitudinal Variation ◽  
Female Head ◽  
Basic Colour ◽  
Epidermal Glands

In a high-altitude population of the Drakensberg crag lizard, Pseudocordylus melanotus, most adult males, unlike adult females, are brightly coloured, and they are larger in body size and have relatively larger heads than females. Three basic colour phases can be distinguished among the brightly coloured adult males. No apparent differences in reproductive activity, number and differentiation state of the generation glands and femoral pores, or scar frequency were noted among the three colour phases. In males the development of bright colours and the differentiation of the epidermal glands coincide with the onset of sexual maturity. Sexual dimorphism in head size of adults is due to a decrease in female head size relative to juvenile head size as well as an increase in relative head size of males. Preliminary data indicate a social structure of territorial polygyny in P. melanotus and suggest that the dimorphism can partly be ascribed to sexual selection. There are also, however, indications of altitudinal variation in the expression of sexual dimorphism, which may be explained in terms of differential energy allocation by females at different altitudes.

Ontogenic allometry and sexual maturity of the hermit crab, Diogenes alias McLaughlin & Holthuis, 2001 (Decapoda, Anomura)

Crustaceana ◽  
2020 ◽  
Vol 93 (1) ◽  
pp. 1-15
Author(s):  
T. Nirmal ◽  
Alexandre Ribeiro da Silva ◽  
A. Pavan Kumar ◽  
A. K. Jaiswar ◽  
Tarachand Kumawat
Keyword(s):  
Sexual Dimorphism ◽  
Sexual Maturity ◽  
Growth Models ◽  
Energy Allocation ◽  
Abundant Species ◽  
Hermit Crabs ◽  
Lack Of Information ◽  
Trawl Fishing ◽  
One Year ◽  
Shield Length

Abstract Growth studies on Anomura, especially hermit crabs, are relatively limited, due to the complexity in constructing generalized growth models as well as the heterogeneity of the group. Despite Diogenes alias being one of the most abundant species in the study area, there is a lack of information regarding its sexual dimorphism and maturity. The present study aims to evaluate its ontogenic allometry, using Jolicoeur’s multivariate allometric coefficient. The specimens were collected biweekly from trawl fishing grounds off the Mumbai coast for one year. Sexual dimorphism was patent at the larger cheliped width in males and the wider shield width in females, which was attributed to the differential energy allocation by both male and female. The size of morphological sexual maturity was established at 7.6 mm shield length for males, and at 6.2 mm in females.

Visual Learning set in a California sea lion

2011 ◽  
Author(s):  
Molly McCormley ◽  
Peter Cook ◽  
Madison Miketa ◽  
Colleen Reichmuth
Keyword(s):  
Visual Learning ◽  
Sea Lion ◽  
California Sea Lion ◽  
Learning Set

Alaska Diary Part 3: Sea lion

Nature ◽  
2003 ◽  
Author(s):  
John Whitfield
Keyword(s):  
Sea Lion

RHYNCHOLITES AND THE PROBLEM OF NARROW AND BROAD CONCEPTION OF TAXONS

2018 ◽  
pp. 12-17 ◽  
Author(s):  
I. R. Khuzina ◽  
V. N. Komarov
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Characteristics ◽  
Mass Scale ◽  
Individual Variability ◽  
Point Of View ◽  
The Other ◽  
New Taxon ◽  
Artificial System ◽  
Broad Understanding

The paper considers a point of view, based on the conception of the broad understanding of taxons. According to this point of view, rhyncholites of the subgenus Dentatobeccus and Microbeccus are accepted to be synonymous with the genus Rhynchoteuthis, and subgenus Romanovichella is considered to be synonymous with the genus Palaeoteuthis. The criteria, exercising influence on the different approaches to the classification of rhyncholites, have been analyzed (such as age and individual variability, sexual dimorphism, pathological and teratological features, degree of disintegration of material), underestimation of which can lead to inaccuracy. Divestment of the subgenuses Dentatobeccus, Microbeccus and Romanovichella, possessing very bright morphological characteristics, to have an independent status and denomination to their synonyms, has been noted to be unjustified. An artificial system (any suggested variant) with all its minuses is a single probable system for rhyncholites. The main criteria, minimizing its negative sides and proving the separation of the new taxon, is an available mass-scale material. The narrow understanding of the genus, used in sensible limits, has been underlined to simplify the problem of the passing the view about the genus to the other investigators and recognition of rhyncholites for the practical tasks.

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