Humans have been fascinated by sleep for millennia. After almost a century of scientific
interrogation, significant progress has been made in understanding the neuronal regulation …

Sleep duration and placement within the twenty-four hour day have been primary indices
utilized in the examination of sleep function. It is of value, therefore, to evaluate these …

Grouped individuals are less vigilant for predators than solitary conspecifics because (1)
grouping increases the likelihood of predator detection (detection effect) and (2) grouping …

Predation is considered one of the most important selective pressures on free-ranging
animals. Our understanding of it derives mainly from studies of individual vigilance (visual …

Every studied animal engages in sleep, and many animals spend much of their lives in this
vulnerable behavioural state. We believe that an explicit description of this vulnerability will …

Since most animals are the prey of others, antipredator behavior is widespread. While
primary defenses, eg, crypsis, aposematism, and mimicry, forestall the attack of predators …

Highlights•Sleep-wake behaviors are regulated by circadian, homeostatic and motivational
processes.•Hypocretin and dopamine neurons link motivational processes with sleep/wake …

Foraging animals are usually simultaneously both predator and prey. This simple truism
dictates that many animals face a profound conflict between predator avoidance and …

Recent studies show that fish forage actively when perceived risk is low, but decrease
foraging and increase vigilance when perceived risk is high. Isolated juvenile chum salmon …

In socially feeding birds and mammals, as group size increases, individuals devote less time
to scanning their environment and more time to feeding. This vigilance “group size effect” …