Walleye is a very common recreational fish in Canada with a strong cannibalism tendency, such that walleyes with larger sizes will consume their smaller counterparts when food sources are limited or a surplus of adults is present. Cannibalism may be a factor promoting population oscillation. As fish reach a certain age or biological stage (i.e. biological maturity), the number of fish achieving...

One hundred and twenty pigs were used to evaluate the effects of housing indoors on concrete slats or outside in dirt lots on tail biting, weight gains, behavior and immune function for pigs with intact tails or with tails docked. Pig performance was largely not influenced by treatments, even when cannibalism was found. When pigs began biting tails in particular pens, many pigs’ tails were not ...

The present studies examined the extent to which (a) communalism, familism, and filial piety would pattern onto a single family/relationship primacy construct; (b) this construct would be closely related to indices of collectivism; and (c) this construct would be related to positive psychosocial functioning and psychological distress. In Study 1, 1,773 students from nine colleges and universiti...

Japan presents a unique social laboratory in which to examine how family support impacts on older adults' psychological wellbeing. This is because of its cultural climate where distinctively different expectations of old-age independence and the traditional norm of filial piety coexist. This study investigated how structural and functional dimensions of the family support of older Japanese pare...

The distribution and behavior of foraging animals usually imply a balance between resource availability and predation risk. In some predators such as scorpions, cannibalism constitutes an important mortality factor determining their ecology and behavior. Climbing on vegetation by scorpions has been related both to prey availability and to predation (cannibalism) risk. We tested different hypoth...

Cannibalism is induced in larval-stage populations of the Hokkaido salamander, Hynobius retardatus, under the control of a cannibalism reaction norm. Here, I examined phenotypic expression under the cannibalism reaction norm, and how the induction of a cannibalistic morph under the norm leads to populational morphological diversification. I conducted a set of experiments in which density was ma...

A simple nonlinear discrete model is derived for the dynamics of a two-age class population consisting of juveniles and adults that includes cannibalism of juveniles by adults. The model is investigated analytically and numerically. It is shown how even this very simple model, by incorporating the negative and positive feedbacks due to cannibalism, can account for several important phenomena co...