Circadian (∼ 24 h) clock regulated biological rhythms have been identified in a wide range
of organisms from prokaryotic unicellular cyanobacteria to higher mammals. These rhythms …

This Review presents a broad overview of adaptations of truly Arctic and Antarctic mammals
and birds to the challenges of polar life. The polar environment may be characterized by …

The circadian clock is an autonomous oscillator that produces endogenous biological
rhythms with a period of about 24 h. This clock allows organisms to coordinate their …

Virtually all species have developed cellular oscillations and mechanisms that synchronize
these cellular oscillations to environmental cycles. Such environmental cycles in biotic (eg …

The behavioural rhythms of organisms are thought to be under strong selection, influenced
by the rhythmicity of the environment,,,. Such behavioural rhythms are well studied in …

Prospective epidemiological studies in industrial societies indicate that 7 h of sleep per night
in people aged 18 years or older is optimum, with higher and lower amounts of sleep …

Long-term tracking using global positioning systems (GPS) is widely used to study
vertebrate movement ecology, including fine-scale habitat selection as well as large-scale …

Coordinated daily rhythms are evident in most aspects of our physiology, driven by internal
timing systems known as circadian clocks. Our understanding of how biological clocks are …

INTRODUCTION Reindeer (Rangifer tarandus) are naturally distributed across the Arctic
and subarctic regions. Consequently, these animals have evolved to face numerous …

Daily interactions between the hypothalamic circadian clock at the suprachiasmatic nucleus
(SCN) and peripheral circadian oscillators regulate physiology and metabolism to set …