Natural Environment Reference


A term used in microbiology to identify specialized cells of the immune system which recognize organisms that invade the body, such as bacteria, viruses, and fungi. Once identified, antibodies then work to eliminate these substances, which are perceived to be a threat to the body in which they have been found.


Movement from one place to another. In the natural world, groups of animals, including humans, migrate together, undertaking often difficult journeys due to seasonal changes, or because of encroaching habitat loss, the loss of natural resources necessary for survival, or other forms of duress. A migration pattern can evolve over time, where the migration route takes on a circular or cyclical form that is followed year after year.

rigor mortis

In Latin, rigor means "stiffness" and mortis means "of death." The term refers to the hardening of muscles after death, which is caused by chemical changes that start immediately after death. This rigidity of the tissues sets in just 2-4 hours after death in humans (longer in other animals), peaks after about 24 hours, and then dissipates gradually until it disappears completely after anywhere between 1-6 days.


Resin is a liquid hydrocarbon secreted by some plants as a form of protection. If the plant is damaged, resin seeps from the wound, hardening as it dries into a protective layer. Natural resin can be harvested sustainably from trees, after which it is rendered into a variety of substances such as varnishes, glues, perfumes, and incense.

Dried resin, known as rosin, in a powdered form is used to increase friction between surfaces, such as between a bow and the strings of an instrument, or the hands of gymnasts and rockclimbers and the surfaces with which they engage. Rosin, which is also known as colophony, is a man-made substance that is produced by distilling the liquid resin until it condenses and solidifies. The final product can range in color; it is usually yellow or orange, but can be almost white or, alternately, close to black. While rosin is solid at room temperature, it melts easily and is used as an ingredient in a variety of products such as soaps, varnishes, adhesives, and sealing materials.

In Tony Hillerman's 1980 Navajo detective novel PEOPLE OF DARKNESS, rosin is mentioned in a natural setting, and probably refers to hardened resin rather than the chemically-produced substance.

red-winged blackbird

As their name suggests, red-winged blackbirds are small birds with mostly all black coloring except for a splash of red (and yellow) on the top of their wings. These birds have a very distinct call, and in many regions, its repeated sound is a sign of Spring. They are common across North America but tend to congregate around wetland areas, and so, if seen in the southwest, it is usually around watercourses, seepage, or springs.


The common raven is a large, heavy-billed black bird. Ravens are larger than crows and have more rugged plumage. Ravens are also the largest perching bird, and can have a wingspan of more than 4 feet. Ravens are very intelligent birds and are known to collect shiny objects. Ravens are scavengers, unlike crows, and are drawn to carrion. As a result, various cultures have associated them with death. Ravens are found in deserts, forests and mountainous areas around the world.

In Navajo teaching, a "two-faced" creature was responsible for both the creation of the world and for bringing death into that same world. Along with coyote, rattlesnake, and spider, raven is considered a "two-faced" creature.


A word that refers to noisy, boisterous behavior.


A venomous pit viper best known for the segmented rattle at the end of its tail. Pit vipers find their prey, even in the dark, through heat-sensing pits located on their faces. There are thirty-three species of rattlesnakes found in North, Central, and South America; however, the main areas with rattlesnakes include northern Mexico and the U.S. Southwest. While rattlesnake venom can be fatal, rattlesnakes are not aggressive and, unless provoked or startled, will not attack. Rattlesnakes come in various colors with geometric patterns, and they can range in length from one to six feet.

Like most reptiles, rattlesnakes lay and brood eggs in late summer, with broods averaging from four to ten young. From birth, these young rattlesnake have fangs and glands that produce a potent venom. As they are young and inexperienced, a young rattlesnake is more likely to attack then an older snake.


The term used to describe an adult male sheep, one that has not been castrated.


A breed of sheep, originally from Spain, with fine crimped wool that is often used to make light sweaters. Merino sheep are medium sized sheep with very wooly faces. They thrive in semiarid environments, including the Southwestern United States.


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