Influence of age and individual identity in the use of breeding colony habitat by male Weddell seals in Erebus Bay, Antarctica

2021 ◽  
Author(s):  
Jamie L. Brusa ◽  
Jay J. Rotella ◽  
Robert A. Garrott
1992 ◽  
Vol 70 (4) ◽  
pp. 680-692 ◽  
Author(s):  
Sherie S. Bartsh ◽  
Shirley D. Johnston ◽  
Donald B. Siniff

The onset of sexual maturity and changes in weight and serum testosterone and cortisol concentrations were studied in male Weddell seals during October–December, 1986, at a breeding colony in McMurdo Sound, Antarctica. Ages were estimated from length or known from tagging history. Underwater copulatory and territorial activities were monitored by colored grease transfer and radiotelemetry, respectively. Hormone concentrations were measured by radioimmunoassay. Of 37 male seals visiting the colony, 22 were resident for ~5 weeks. About one-third of the male residents defended territories into estrus and were called territorial (T). Another one-third appeared unsuccessful at defending a territory and were called transitional (TN). The remaining one-third were nonterritorial (N). Males were closely matched in size (coefficient of variation ≤ 15% for length, girth, and weight). Most N males were 5–7 years old. T males (≥ 7 years old), being older (P < 0.05) than N males, attained 19 of 20 observed copulations. T males were heavier initially (P < 0.10) than TN or N males, and they lost more weight during the breeding season (P = 0.08, 3.2 vs. 2.1 kg/day) than N males. In all males, serum testosterone and cortisol concentrations declined, approaching nadir as estrus and the breeding season ended. Mean (±SE) daily concentrations ranged from 6.8 ± 2.4 ng/mL to nondetectable concentrations for testosterone and from 104.8 ± 13.2 to 54.7 ± 4.5 μg/dL for cortisol. Concentrations of both hormones were higher in T males than in N males. Hormone profiles of TN males initially resembled those of T males, but at estrus resembled those of N males. Coincident with a change in competitive behavior was a transient rise in cortisol accompanied by a drop in testosterone.


2016 ◽  
Vol 2 (2) ◽  
pp. 40
Author(s):  
Miriam Aparicio

This study tests some hypotheses included in the psycho-social-communicational paradigm, which emphasizes the cognitive effects of the media and the role of the psychosocial subject as the recipient


2017 ◽  
Vol 1 (1) ◽  
pp. 15-31
Author(s):  
Francisco Xavier Morales

The problem of identity is an issue of contemporary society that is not only expressed in daily life concerns but also in discourses of politics and social movements. Nevertheless, the I and the needs of self-fulfillment usually are taken for granted. This paper offers thoughts regarding individual identity based on Niklas Luhmann’s systems theory. From this perspective, identity is not observed as a thing or as a subject, but rather as a “selfillusion” of a system of consciousness, which differentiates itself from the world, event after event, in a contingent way. As concerns the definition  of contents of self-identity, the structures of social systems define who is a person, how he or she should act, and how much esteem he or she should receive. These structures are adopted by consciousness as its own identity structures; however, some social contexts are more relevant for self-identity construction than others. Moral communication increases the probability that structure appropriation takes place, since the emotional element of identity is linked to the esteem/misesteem received by the individual from the interactions in which he or she participates.


2001 ◽  
Vol 35 (2) ◽  
pp. 140-146 ◽  
Author(s):  
R. H. Foote ◽  
E. Hare

Rabbit seminal plasma catalase is much higher than in the semen of other mammals, and differences appear to be inherited. Because of the scarcity of information on rabbit blood catalase and haematocrit in Dutch-belted rabbits, an investigation of possible effects of gender, age and genetics on these variables was undertaken. There were 191 rabbits sampled at 2-3 months, 130 at 12 months and 61 at 18-24 months of age. There was no age effect on the haematocrit values and on blood catalase activity. At 12 months of age males had an average haematocrit value of 44% compared with 40% for females ( P < 0.05). Corresponding average catalase values were 431 and 356 units/ml of blood ( P < 0.05). Also catalase was measured in the semen and blood of 34 males, and males differed in both their blood and semen catalase activity ( P < 0.05). The correlation between the two traits was r = 0.44. Heritability ( h2) estimates, based on 231 rabbits were 0.40 for blood catalase activity, and 0.26 for haematocrit. The genetic correlation between the two variables was 0.83 ( P < 0.05). These studies are consistent with the literature in that female rabbits have a slightly lower haematocrit value than males, and this is associated with a lower catalase activity. This appears to be the first report of a study that compares rabbit blood catalase in males and females of different ages. Preliminary evidence that differences may have a heritable basis is consistent with previous studies on rabbit semen catalase.


2021 ◽  
Author(s):  
David A. Ehlers Smith ◽  
Brent Coverdale ◽  
Ben Hoffman ◽  
Christopher Kelly ◽  
Yvette C. Ehlers Smith ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document