Family – the usual major subdivision of an order or suborder in the classification of organisms
Fang – a long, pointed tooth; in some groups, fangs are hollow and used for injecting venom
Feather – a keratinous outgrowth of the skin of birds that is highly modified for the purposes of flight, insulation, and display
Feliform – suborder of the Carnivora including the cats and their relatives
Filter Feeder – an animal that feeds by straining suspended matter and food particles from water, typically by passing water over a specialized filtering structure
Fin – an appendage of fish and fishlike aquatic animals used for locomotion
Fish – any cold-blooded, legless aquatic vertebrate that possess a series of gills on each side of the pharynx, a two-chambered heart, no internal nostrils, and at least a median fin as well as a tail fin
Flehmen – behavior exhibited by some mammals where the animal raises its head with the mouth partly open and upper lip slightly drawn back to take in scents/pheromones
Flipper – a flattened forelimb evolved for aquatic locmotion
Flocculus – either of two small lobes on the lower border of that brain that in birds help process sensory information during flight
Fluke – the flattened appendage at the end of cetacean tails
Folivore – an herbivore that feeds on leaves
Food Web – a diagram that represents the feeding relationships of organisms within an ecosystem
Fossil – the remains of a once-living organism
Fossorial – adapted for burrowing
Frugivore – an herbivore that feeds on fruit
Fur – the short, fine, soft hair of certain mammals
Gastrolith – a stone that is ingested into the stomach and acts as a masticatory agent
Gastropod – a mollusk characterized by an asymmetrical form, true head, unsegmented body, and a broad, flat foot
Genus – a principal taxonomic category that ranks above species and below family
Gill – the respiratory organ of an aquatic animal consisting of an outgrowth of the body surface or an internal layer of modified gut, past which water flows
Gill Raker – one of a set of stiff, toothlike processes located on the inner side of the gill arch which strain the water flowing past the gills
Granivore – an herbivore that feeds on seeds
Grazer – an herbivore that feeds on grass
Hair – any of the fine, threadlike strands growing from the skin of mammals and some other animals
Hematophagy – feeding on blood
Hemotoxin – toxin that destroys red blood cells, disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage
Herbivore – an animal that eats plants
Hermaphrodite – an individual that posses both male and female sex organs
Heterodont – possessing teeth that are differentiated into several forms
Hibernation – a strategy for surviving cold winters where the animal’s metabolic rate is reduced to a minimum and it enters a deep sleep, surviving on food reserves stored in the body during the favorable summer period
Homodont – possessing teeth all of which are of the same form
Hoof – the horny covering protecting the ends of the digits or encasing the foot in certain animals
Horn – one of the bony, permanent hollow paired growths that project from the upper part of the head of certain ungulates
Hypercarnivore – a carnivore whose diet is 70% or more vertebrate flesh
Hypocarnivore – a carnivore whose diet is 25% or less vertebrate flesh
Hypsodont – teeth in which the crowns are high and the roots are short
Ice Age – a period of long-term reduction in temperature of Earth’s surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers
Incisor – one of the chisel-shaped teeth at the front of the mouth
Index Fossil – a fossil whose presence is characteristic of a particular unit of rock in which it occurs
Insect – class of arthropods that have three pairs of legs and usually two pairs of wings on the thorax
Insectivore – an animal that feeds on insects
Invasive Species – an organism that is not native to a specific location and which has a tendency to spread to a degree believed to cause damage to the enivronment, human economy, or human health
Invertebrate – an animal lacking a backbone
Iridiophore -a cell containing iridescent crystals that allow for the absorption and/or reflection of certain wavelengths of light and used by chameleons to change color
Ivory – the hard white substance composing the main part of the tusks of certain mammals