Natural Environment Reference

A pair of fused bones that make up the lower portion of the heads of creatures. Also known as the mandible, the lower jawbone hinges just under the cheekbone and is used to crush, pulverize, and masticate solid food.

A young male horse, under the age of four, that has not been castrated.

A hormone, also known as epinephrine, that is secreted by the adrenal glands, especially when a person is under stress, because it increases the body's ability to respond to threats. While spelling adrenalin without an extra "e" is technically correct, the more common spelling of this word is adrenaline with the "e."

The anatomical place in the body where two bones meet. A joint can either move or be fused. There are three types of joints. A fibrous joint occurs when two bones are connected by fibrous tissue and does not articulate or bend. The skull is an example of bones connected by fibrous joints. Cartilaginous joints occur when bones are connected by cartilage, which allows limited movement between bones. Examples of cartilaginous joints are the connections between the manubrium, the sternum, and the xyphoid process, the are on the chest where the ribs meet at the breast bone. A synovial joint occurs when bones are not directly connected and are therefore able to articulate through a wide range of positions. This movement is facilitated by the lubricating presence of synovial fluid between bones ends. The bones of the fingers, wrists, shoulders, and knees are all examples of synovial joints.

Smooth muscle tissue, usually associated with organ function, that an individual does not consciously choose to use. Instead, the operates, or performs its function automatically. The heart is an involuntary muscle.

A medium-sized antelope found in the savanna and woodland habitats of eastern and southern Africa. Impalas move in big herds as a strategy of protection against predators. If one impala detects the presence of a predator (a lion, for example), it will bark an alarm, and the whole herd will promptly flee. Impalas are fast runners, can leap in bounds as long as 33 feet, and soar up to 10 feet in the air. The impala is known and coveted for its long, curved horns. Due to extensive hunting, loss of habitat, and interbreeding, it is now declared an endangered species.

A wild goat population whose natural habitat is in mountain ranges in parts of Africa, the Middle East, Europe, and Asia. The ibex is famous for its hardiness and agility, living in the rocky, rugged terrains of high mountains. It is easily recognized by the long, back-curving horns of the male. Ibex populations across the world have been declining due to extensive hunting and habitat loss, but the species is not endangered.

The colloquial name for a genus (Bouteloua) of perennial or annual grasses that grows in clumps or tufts throughout North America and includes such range grasses as: black grama, hairy grama, blue grama, and sideoats grama. The genus Bouteloua was named after Spanish botanists, Claudio and Esteban Boutelou.

Horsefly, also spelled horse fly, is the common name for any of more than 2000 insects from the family Tabanidae. The male horsefly feeds on pollen and nectar while the female horsefly feeds on blood and is a common pest of animals and sometimes humans. These flies range in size from as small as a housefly to as large as a bumblebee and are found all around the world.

The horse was introduced to the Americas in the 1500s by the Spaniards. While the Spaniards prized the horse for the role it played in travel, exploration, and war, they at times left herds of horses in various locales, hoping that the animal would find ways to establish itself on the continents the Spanish were busily conquering. The horse proved very adaptable and found habitats to thrive in, especially in the Great Basin and Plains of North America. Native Americans, particularly along Spain's northern colonial frontier, emulated the Spaniards' use of the horse for transportation, hunting, labor, and sport, and soon out-mastered the Spanish horsemen in riding, training, and cultivating the beasts the Spanish so prized. The horse took on great significance to many indigenous communities, and in some cases was incorporated into origin stories as a gift from the gods. The horse also occupies a central role in many mythologized frontier narratives about the Western and Southwestern regions of the United States.