C

Caching
The storage or hoarding of food for later eating during times of limited food availability.

Caecilian
A group of amphibians that have long bodies (often with rings), no limbs, and virtually no tail. Earthworm-like in appearance.

Caiman
A relative of the alligator that is found in Central and South America.

Calamus
The hollow, proximal portion of the feather shaft that attaches the feather to the skin.

Calcereous
Describes structures that contain calcium such as shells, exoskeletons, and bones and function to support or protect an animal.

Call Matching
A vocalization in birds characterized by the male and female of a pair duplicating the other's flight call. Call matching is often a behavior exhibited by members of the finch family.

Cambrian Explosion
The Cambrian Explosion (570 to 530 million years ago) refers to an unprecedented and unsurpassed period of evolutionary innovation in the history of our planet.

Cambrian Period
The Cambrian Period (543 to 505 million years ago) is the first time period of the Paleozoic Era. It is preceded by the Precambrian.

Camouflage
Coloration or patterns that help an animal to appear to blend with its surroundings. Camouflage is common among invertebrates.

Candidate Species
A species of plant or animal for which FWS or NOAA Fisheries has sufficient information about its biological vulnerability and threats to warrent a proposal to list as endangered or threatened.

Canine Tooth
A sharp tooth positioned near the front of the jaws present in mammals (and most prominent in carnivores) that has a single point that is shaped for peircing and holding onto food.

Carapace
A hard shell or shield-like structure on the dorsal side of an animal's body. Also refers more specifically to the upper side of a turtle or tortoise shell.

Carboniferous Period
The Carboniferous Period (360 to 286 million years ago), also known as the Age of Amphibians, is the fifth of six periods during the Paleozoic Era.

Carnasial Tooth
A sharp, premolar tooth present in carnivores that is adapted for efficient tearning and slicing through the meat of their prey.

Carnivore
An animal that consumes primarily the flesh of other animals. More specifically used in reference to members of the Order Carnivora.

Carotenoids
Carotenoids are a class of organic pigments that absorb blue light and as a result are responsible for red, orange, and yellow hues.

Carrying Capacity
The number of individuals in a population that can be supported on the resources of a habitat.

Caruncle
A bright-colored area of skin (featherless) on the face or neck of a bird (most prominent in turkeys and relatives).

Casque
A raised structure located on the head of a lizard (usually grows at the rear of the lizard's head).

Caste
A group of individuals that belong to the same social group that share some specialized form or behavior.

Central Nervous System
The part of an animal's nervous system that is made up of interneurons and exerts some control over the rest of the nervous system.

Centrifugal Tail Molt
The shedding and replacement of a bird's tail feathers that begins with the innermost pair of feathers being replaced first and then proceeding from the center outward.

Cephalization
The localization of neural control and sensory organs at the anterior end of an animal's body.

Cere
In birds (especially raptors), a raised and fleshy patch located at the base of the upper mandible (maxilla).

Cetaceans
The order of marine mammals that includes toothed whales and toothless, filter-feeding (baleen) whales.

Character Displacement
The divergence of adaptations or other characteristics in two similar species in locations where the animals share habitat.

Chitin
A polysaccharide polymer that is found in invertebrate exoskeletons, the shells of some mollusks, and the cell walls of fungi.

Chytridiomycosis
Chytridiomycosis is a leathal skin disease that affects amphibians. Chytridiomycosis is caused by the chytrid fungus Batrachochytrium dendrobatidis.

Clade
Clade

Cladistics
The area of study concerned with depicting phylogeny.

Clappering
In birds (especially storks), a non-vocal form of communication expressed by the slapping together of the upper and lower parts of the bill together.

Clean Air Act
The Clean Air Act was first enacted in 1970 and authorized the establishment of federal and state regulations that limit emissions stationary and mobile sources of air pollutants.

Clean Water Act
The Federal Water Pollution Control Act, also known more commonly as the Clean Water Act, came into effect in 1972. This Clean Water Act is the primary legislation concerning water pollution and its regulation.

Climax
The point at which an ecological community has completed a successional sequence, or sere and has reached a steady state within a particular set of environmental conditions.

Climograph
A graph that depicts the annual cycle of temperature and rainfall for a geographical locations.

Cloacal Spur
A spur or claw in boas and pythons that is a remnant of the pelvic girdle or hindlimb and is used by the male snake in courtship.

Clutch
A group of eggs (and the resulting group of young) produced by a female for a single breeding attempt.

Cnidaria
The taxonomic group (phylum) of animals whose members are characterized by radial or biradial symmetry, diploblastic organization, and possess a gastrovascular cavity and nematocysts.

Coelenterates
A group of primitive aquatic animals that includes jellyfish, corals, and sea anemones.

Collar
A narrow band of pigment (in reptiles) that extends across the nape of the neck.

Colt
A male horse, up to four years old.

Coltan
Columbite-tantalite or 'coltan' is a metallic ore found in Australia, Canada, Brazil, and central Africa.

Competition
In ecology terms, competition arises when two or more individuals (or populations) rely on the same limited resource. In doing so, both parties are impacted negatively.

Conditioning
A type of learning in which associations are made. Learning can be acquired through stimulus-response or reward-punishment reinforcement.

Conservation
Conservation is the artificial control man imposes upon ecological relationships in a habitat, community, or ecosystem in order to sustain balance among the species it supports.

Constriction
A method many non-venomous snakes used to kill prey that involves the snake coiling around its prey and tightening its grip to suffocate the prey.

Contour Feathers
The outer layer of feathers that cover a bird's body, wings, and tail and give the bird its characteristic appearance.

Convention on International Trade in Endangered Species (CITES)
A convention established in 1973 that regulates or prohibits the international trade of plant and animal species that are believed to be harmed by or that may be harmed by international trade.

Convergent Evolution
Evolutionary change in two or more unrelated organisms that results in the independent development of similar adaptations to similar environmental conditions.

Corallum
The skeleton of a colonial coral which, in turn, consists of individual corallites.

Costal Grooves
A set of parallel, vertical grooves present on the sides of some salamanders, newts, and their larvae.

Countershading
A coloration pattern in the plumage of some birds in which the underparts of a bird are light in color while the upper parts of the bird are darker.

Craniate
Craniates are a group of chordate animals that include hagfish, lampreys, and the jawed vertebrates such as cartilaginous fishes, bony fishes, and tetrapod vertebrates.

Creche
A group (flock) of unrelated young birds gathered together for protection.

Cretaceous Period
The Cretaceous Period (144 - 65 Myr BP) is the third of three periods during the Mesozoic Era. It is preceded by the Jurassic Period and followed by the Tertiary Period.

Critical Habitat
Areas of habitat that are crucial to the survival of a species and essential for its conservation and that have been formally designated as such by rule published in the Federal Register.

Crocodile
A crocodilian that inhabits tropical regions. A crocodile differs from an alligator in that it has a narrower snout.

Crop
An expandable pouch in the esophagus of some birds (members of the Order Gruiformes do not have a crop).

Cryptic
Pertaining to characteristics that serve to conceal an animal.

Chronobiology
The field of biology that examines the rhythms (timing and duration) of biological activity or phenomena (eating, sleeping, mating, migration, cellular regeneration, etc.).