Arctic: A region that falls within the Arctic Circle. The edge of that circle is defined as the northernmost point at which the sun is visible on the northern winter solstice and the southernmost point at which the midnight sun can be seen on the northern summer solstice. The high Arctic is that most northerly third of this region. It’s a region dominated by snow cover much of the year.
biology: The study of living things. The scientists who study them are known as biologists.
brain waves: Electrical signals produced through the coordinated activity of billions of nerve cells in the brain of an animal. When charted, the signal typically looks wavy or spiky.
chronobiologist: A scientist who studies circadian rhythms.
coauthor: One of a group (two or more people) who together had prepared a written work, such as a book, report or research paper. Not all coauthors may have contributed equally.
digest: (noun: digestion) To break down food into simple compounds that the body can absorb and use for growth. Some sewage-treatment plants harness microbes to digest — or degrade — wastes so that the breakdown products can be recycled for use elsewhere in the environment.
electrode: A device that conducts electricity and is used to make contact with the non-metal part of an electrical circuit, or that contacts something through which an electrical signal moves. (in electronics) Part of a semiconductor device (such as a transistor) that either releases or collects electrons (negative charges) or holes (positive charges) — or that can control their movement.
indigenous: Native to some region. (in anthropology) An adjective (and capitalized) for people that have lived for eons in some region, developing a culture that reflects the resources, climate and ecosystems of that place.
insight: The ability to gain an accurate and deep understanding of a situation just by thinking about it, instead of working out a solution through experimentation.
lichen: A blend of a fungus and an alga. Neither of these organisms is a plant; the lichen isn’t a plant either. Slow-growing, lichens organisms live on the surface of rocks, trees or wood over many years. Lichens are a component of the soil crusts or “desert crusts” that cover the soil in some deserts .
neurobiologist: Scientist who studies cells and functions of the brain and other parts of the nervous system.
neuroscientist: Someone who studies the structure or function of the brain and other parts of the nervous system.
physiological: Having to do with the branch of biology that deals with the everyday functions of living organisms and how their parts function. Scientists who work in this field are known as physiologists.
predator: (adjective: predatory) A creature that preys on other animals for most or all of its food.
REM sleep: A period of sleep that takes its name for the rapid eye movement , or REM, that occurs. People dream during REM sleep, but their bodies can’t move. In non-REM sleep, breathing and brain activity slow, but people can still move about.
tundra: A cold, usually lowland area in far northern regions. The subsoil is permanently frozen. In summer, a tundra’s top layer of soil thaws and can support low-growing mosses, lichens, grasses, shrubs and trees (some only a few centimeters high).