scholarly journals Different patterns of allopreening in the same‐sex and opposite‐sex interactions of juvenile large‐billed crows ( Corvus macrorhynchos )

Ethology ◽  
2019 ◽  
Vol 126 (2) ◽  
pp. 195-206 ◽  
Author(s):  
Eri Miyazawa ◽  
Akiko Seguchi ◽  
Nana Takahashi ◽  
Ayumi Motai ◽  
Ei‐Ichi Izawa
2015 ◽  
Vol 24 (10) ◽  
pp. 1622-1628 ◽  
Author(s):  
Linda J. Ahrenfeldt ◽  
Axel Skytthe ◽  
Sören Möller ◽  
Kamila Czene ◽  
Hans-Olov Adami ◽  
...  
Keyword(s):  
Same Sex ◽  

1978 ◽  
Vol 47 (3) ◽  
pp. 955-962 ◽  
Author(s):  
Nancy J. Bell ◽  
Kay Hibbs ◽  
Thomas Milholland

Male and female college students were presented with a photograph labeled as a 5-yr.-old boy or girl and heard statements attributed to the child. They then rated the child on sex-role traits and responded to open-ended questions about the child. The primary findings involved sex of child by sex of adult interactions on ratings of independence and leadership: in both cases, same-sex children were rated higher than opposite-sex children. There was also some evidence that women having high contact with children rated the child more extremely on opposite-sex traits than did those with little contact.


2019 ◽  
Vol 63 (3) ◽  
pp. 303-328
Author(s):  
Monicah Kareithi ◽  
Frans Viljoen

AbstractWoman-to-woman marriage is a form of customary marriage between two women, predominantly found in Africa. These customary marriages have been and to some extent still are conducted by various communities across Africa, including in Kenya. Communities such as the Kamba, Kisii, Nandi, Kikuyu and Kuria practise woman-to-woman marriages for a variety of reasons. The legal status of woman-to-woman marriages in Kenya is uncertain due to the provisions of article 45(2) of Kenya's Constitution of 2010 and section 3(1) of the Marriage Act of 2014, which stipulate that adults only have the right to marry persons of the opposite sex. However, a holistic and purposive reading of the constitution, taking into consideration its recognition of culture and the protection of children as important values in Kenyan society, and considering the historical context within which the provisions concerning same-sex marriages were included, leads to the conclusion that these provisions were not intended to proscribe the cultural practice of woman-to-woman marriage in Kenya. The constitutional validity of woman-to-woman marriage opens the door to a more expansive and fluid understanding of “family” in Kenya.


2014 ◽  
Vol 281 (1793) ◽  
pp. 20141261 ◽  
Author(s):  
Elizabeth A. Archie ◽  
Jenny Tung ◽  
Michael Clark ◽  
Jeanne Altmann ◽  
Susan C. Alberts

Social integration and support can have profound effects on human survival. The extent of this phenomenon in non-human animals is largely unknown, but such knowledge is important to understanding the evolution of both lifespan and sociality. Here, we report evidence that levels of affiliative social behaviour (i.e. ‘social connectedness’) with both same-sex and opposite-sex conspecifics predict adult survival in wild female baboons. In the Amboseli ecosystem in Kenya, adult female baboons that were socially connected to either adult males or adult females lived longer than females who were socially isolated from both sexes—females with strong connectedness to individuals of both sexes lived the longest. Female social connectedness to males was predicted by high dominance rank, indicating that males are a limited resource for females, and females compete for access to male social partners. To date, only a handful of animal studies have found that social relationships may affect survival. This study extends those findings by examining relationships to both sexes in by far the largest dataset yet examined for any animal. Our results support the idea that social effects on survival are evolutionarily conserved in social mammals.


2006 ◽  
Vol 9 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Sioban Laffey-Ardley ◽  
Karen Thorpe

AbstractArecent large-scale study of Finnish adolescent twins (Pulkkinen et al., 2003) reported that individuals from opposite-sex twin pairs were more socially adaptive than individuals from same-sex pairs or singletons. This finding raised questions about the social learning effects of being an opposite-sex twin. The current article predicted on the basis of this finding, and evidence from singleton populations, that having an opposite-sex twin would yield social advantage. It sought to examine the social competencies of opposite-sex twins and compare them with same-sex twins and singletons. The study focused on the preschool years (age 3 to 6), a period in which the majority of children encounter their first large group, nonfamilial social experiences. The study obtained reports from parents and teachers of children aged 3 to 6 years: 72 children (36 pairs) who were dizygotic opposite-sex twins (DZOS), 50 children (25 pairs) who were dizygotic same-sex twins (DZSS), and 85 singletons of the same age and sex as the twins, who had at least one sibling. Reports were made using standardized measures of social competencies, behavior problems, language development and friendships. The main effects found were of differences in social competency between twins and singletons. Twins had lower social competency scores. No differences between same-sex and opposite-sex twins were found. The findings did not support the hypothesis of social advantage for opposite-sex twins in early childhood.


2018 ◽  
Vol 33 (5) ◽  
pp. 930-934 ◽  
Author(s):  
Satoshi Kanazawa ◽  
Nancy L Segal ◽  
David de Meza

Author(s):  
Steven Arnocky ◽  
Tracy Vaillancourt

Darwin (1871) observed in his theory of evolution by means of sexual selection that “it is the males who fight together and sedulously display their charms before the female” (p. 272). Researchers examining intrasexual competition have since focused disproportionately on male competition for mates, with female competition receiving far less attention. In this chapter, we review evidence that women do indeed compete with one another to secure and maintain reproductive benefits. We begin with an overview of the evolutionary theory of competition among women, with a focus on biparental care and individual differences in men’s mate value. We discuss why competition among women is characteristically different from that of men and highlight evidence supporting women’s use of epigamic display of physical attractiveness characteristics and indirect aggression toward same-sex peers and opposite-sex romantic partners as sexually competitive tactics. Finally, individual differences in competition among women are discussed.


Author(s):  
Zdeňka Králíčková

The paper deals with couples in de facto unions, especially the ones formed by a man and a woman. It seeks to define cohabitation and differentiate the rights and duties of cohabitees from the ones connected with the status relations between both the opposite-sex couples (marriage) and the same-sex couples (registered partnership). As there are seldom any kinds of agreements between cohabitees, special attention is devoted to the relevant legal rules in all the Books of the Czech Civil Code and their applicability to cohabitees during their relationship and after the break-up or upon the death of one of them. It is stressed that there is no difference between children born out of wedlock and within marriage. Once parenthood is legally established, there is no discrimination of non-married mothers and non-married fathers towards the children. And besides, there are special provisions that protect the weaker party: property claims of the non-married mother from the child´s father for a reasonable time and within adequate limits.


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