Largely based on pre-theory that ties high testosterone (T) to masculinity, and low T to
femininity, high T is mainly studied in relation to aggression, mating, sexuality, and …

Considerable evidence suggests that the steroid hormone testosterone mediates major life-
history trade-offs in vertebrates, promoting mating effort at the expense of parenting effort or …

Relatives have more similar gut microbiomes than nonrelatives, but the degree to which this
similarity results from shared genotypes versus shared environments has been …

For social species, the environment has two components: physical and social. The social
environment modifies the individual's interaction with the physical environment, and the …

In multimale groups where females mate promiscuously, male–infant associations have
rarely been studied. However, recent studies have shown that males selectively support …

Preferential affiliative relationships, or social bonds, play a crucial role in primate social life,
but little is known about their development. Here, we review macaque studies investigating …

Inbreeding often imposes net fitness costs, 1–5 leading to the expectation that animals will
engage in inbreeding avoidance when the costs of doing so are not prohibitive. 4–9 …

Social development is crucial in the ontogeny of animals living in complex societies and has
lasting consequences in adulthood. Spotted hyenas (Crocuta crocuta) live in fission-fusion …

The diversity of competing frameworks for explaining the evolution of non-maternal care in
mammals (Part I, this issue) reflects the vast range of behaviors and associated outcomes …

The steroid hormone testosterone (T) is a well-known mediator of male sexual behavior in
vertebrates. However, less is known about T's rapid effects on sexual behavior, particularly …