Animal Glossary A-Z: Dictionary Of Animal Terms

Some animal vocabulary words are technical and hard to understand.

This animal glossary contains an alphabetical list of animal terms explained in concise detail.

Contents show

A

Abdomen

  • The part of the body between the thorax and pelvis in vertebrates. 
  • The third section of an insect’s body, after the head and thorax. 

Acanthodian

 An extinct class of fish with jaws.

Adaptation

The ability of animals to develop behavior and evolutionary changes in order to survive in their habitat and adjust to changing circumstances. 

Aestivation

A state of dormancy in animals characterized by reduced metabolic rate and inactivity. It often occurs in the summer and is necessary to survive harsh conditions such as droughts and high temperatures. 

Age of Fledgling

The age at which birds develop wing feathers strong enough to take their first flight. 

Age of Independence

The age at which animals become strong enough to survive in the wild without parental assistance. 

Age of Sexual Maturity

The age at which animals become sexually developed to produce offspring. 

Agnathan

A biological phylum classification that refers to fishes without jaws. 

Ammonite

An extinct class of mollusk marine creatures known for their spiral shells. 

Amniotes

Vertebrates, reptiles, birds, and synapsids that lay eggs on land or retain eggs within mothers. They possess membranes protecting them as embryos and develop without the larval stage. 

Amphibian

Vertebrates that reside in water as larvae with gills and metamorphosize to develop lungs to live on land as adults and return to water to breed. 

Amplexus

Mating behavior in amphibians in which males grasp females from behind with their front legs and fertilize the eggs with delay as the female releases them. 

Anal Claspers

Projections seen at the end of caterpillars that make dragonflies capable of grasping prey. 

Anamniotes

Group of animals such as fishes and amphibians that lay eggs on water. 

Anaphylactic Shock

Allergic reactions by humans and mammals from insect stings characterized by low blood pressure, trouble breathing, weak pulse, pale skin, skin rash, nausea, and vomiting. 

Anapsid

Amniotes with skulls that lack one or more holes or openings near the temple. 

Anatomy 

The internal and external structure of an animal’s body. It includes the position of organs, body shapes, and bone structure. 

Animal 

Multicellular eukaryotic organisms classified under the biological kingdom Animalia.

All organisms under the Animalia classification possess the ability to reproduce sexually, breathe in oxygen, are motile, and consume organic materials.

They develop from zygotes at fertilization to become multicellular embryos. Animals are classified into species, the basic unit of biological classification.

There exist about 1.5 million living animal species. They coexist and interact through intricate, complex relationships such as food webs which affect every aspect of life.

Ancestor

A related form of present animals.

Annelids 

A biological group of segmented or ringed tubular bodies.  

Antennae

Pairs of long, slender appendages in insects, crustaceans, and some arthropods sensitive to taste, smell, sound, heat, and touch.

Its size and shape vary depending on the species of insects, crustaceans, and arthropods. 

Antivenin

Medications containing antibodies used to counteract the effects of venoms.

Antlers 

Extension of skulls found on the heads of deers and the Cervidae biological family composed of bones, blood vessels, cartilages, nerves, and skin. 

Apex Predators 

Animals atop the food chain, that, as adults, do not get preyed on by other animals. They are integral to a functioning ecosystem as they ensure continuity and maintain biodiversity. 

Aphids

Small insects that suck tree saps and secrete honeydew. 

Aquatic

Relating to water and the creatures that reside in water bodies. 

Arachnid

A biological class of invertebrate animals characterized by their jointed legs. 

Arboreal Locomotion 

The movement of animals that reside in trees. It also refers to the motion of animals while they are on a tree, even if they do not reside in trees. 

Archosaurs

A group of diapsids that primarily include crocodiles and birds as the only living members. 

Arthropod

Invertebrate animals that have exoskeletons, segmented bodies, and jointed appendages. 

Artiodactyl

Hoofed mammals that bear weight on the even number of toes on their feet. 

Asexual Reproduction 

A form of reproduction that requires one parent to produce offspring. 

It is common in invertebrates, and often organisms exhibiting such behavior reproduce in large numbers. 

Autotomy

A survival or self-defensive behavior in animals where they possess the ability to shed parts of their appendages to escape the grasps of a predator. 

Average Clutch Size

The number of eggs an animal lays in one nesting. 

Average Lifespan

A statistical hypothesis that determines the average duration of an animal’s life. 

Average Litter Size

The number of young ones an animal can birth at a time. It is often equal to one-half of the teats the animal possesses. 

Average Size

The height, length, and weight an animal is expected to reach, based on statistical hypothesis.  

Average Spawn Size

The number of eggs a fish can lay at a single time. 

Average Weight

The estimated weight of an animal based on statistical hypothesis. 

B

Backbone

A long bone on the back of vertebrates responsible for support. It is made up of small vertebrae and is also referred to as the spine. 

Baleen

A filter-feeding mechanism made up of keratin found in the mouths of whales. It bears similarities to animal bristles. 

Barb

A biological group of ray-finned fish species. 

Beak

External anatomical horny structure projecting from the mouths of mostly birds, turtles and few mammals. 

Beast of Burden 

Animals used to carry loads. 

Benthic

Relating to the depths of a water body or the animals that reside in the depths of a water body. 

Biggest Threat 

Biological factors that pose significant danger to animals and their habitats, e.g., deforestation.

Bill

Beak of animals.

Binocular Vision 

Vision in animals with which their two eyes can face the same direction to perceive a three-dimensional view of their surroundings in order to judge depth. 

Biome 

A biological habitat formed as a result of regional climate and the living organisms residing in it. 

Bipedal 

Capable of moving on two legs. 

Bird

A biological group of warm-blooded vertebrates belonging to the Aves class characterized by the presence of feathers, high metabolism, four-chambered heart, lightweight skeleton, beaked jaws without teeth, and reproduction through laying of eggs with hard shells. 

Bivalve

A biological group of freshwater mollusks that possess two proportional shells. 

Bird of Prey

Hypercarnivorous birds that hunt and feed on other vertebrates, reptiles, and mammals.

Blubber

Layers of fat found under the skin of cold-blooded marine animals. 

Bovines 

A biological group of animals that are members of the ungulates.

Blowhole 

The nostrils of dolphins and whales positioned atop their foreheads. 

Brachiation

A form of arboreal locomotion carried out by primates which involves swinging from one tree limb to another with their arms. 

Brackish

Water bodies that have more salinity than fresh water but are not seawater. It is formed by the mixture of seawater and freshwater and is often where the river meets the ocean. 

Breaching 

The behavior exhibited by cetacea (aquatic mammals) which involves jumping out of the ocean and falling back with a big splash. 

Breeding Season

A period in the year when male and female animals of the same species come together for the purpose of mating. 

Brille

A layer of transparent, immovable scale covering the eyes of some animals, e.g., snakes, and lizards. 

Brood Parasite

Animals that trick other animals into raising their young ones. 

Browsing 

A behavior in herbivores which involves eating leaves, shoots, and fruits of high-growing plants and shrubs.

Bufagin

A poisonous secretion of the skin gland found on the back of the neck of amphibians. 

Bug

A small insect with needle-like mouthparts for sucking food. 

C

Calcareous

Structures made up of calcium in animals that provide support and protection. They include exoskeleton, shells, and bones. 

Camouflage

Colors and patterns used by animals to blend with natural environments. 

Canid

A member of the canine biological group. 

Canine Tooth

The long pointed teeth in animals. 

Cannibalism

The act of feeding on an individual of the same species. 

Carnassial Tooth

The lower and upper teeth towards the edge of the mouth used for shearing. 

Carapace

The upper part of the exoskeleton or the protective shell of an animal. 

Carcass

The remains of an animal

Carnivore

Animals that feed on the flesh or tissues of other animals. 

Carrion

The decaying remains of an animal fed upon by scavengers. 

Cartilage

The connective tissue found in the skeleton of animals. 

Casque

An extension of the bony structure on the upper mandible of the skull of birds, and some amphibians, and reptiles.

Cathemeral

The act of being able to engage in activities necessary for survival, such as acquiring food and socializing, by day and night. 

Cell

The smallest basic unit of life responsible for life’s processes.  

Cellulose

A complex carbohydrate secreted by plants, which can only be digested by herbivores with the aid of microorganisms. 

Cephalopod

A biological class of mollusk characterized by tentacles, a prominent head, and a bilateral body. 

Cephalothorax

A section of the bodies of arthropods and arachnids where the head and thorax are fused together. 

Cerci

A single appendage located found at the rear parts of arthropods, which serve as sensory organs. 

Cetacean

A member of the aquatic mammal biological group cetacea. 

Chelicerae

The mouth and jaws of arachnids which may contain fangs. 

Chordate

 A member of the phylum chordata. 

Chelonian

A member of the order Testudines such as turtles and tortoises. 

Chemoreceptor

Sensory cells in animals and plants that can detect particles in air and water, and generate a biological signal by conversion of chemical substances to form sensory stimuli. 

Chrysalis

A hard, shiny case that protects the pupa of insects such as the butterfly.  

Cilia

Tiny threadlike projections found on microorganisms, and some cells used for directing the flow of fluids outside the cells or microorganisms. 

Circulatory System

A system of organs in animals made up of the heart and blood vessels, which circulates the flow of blood through the entire bodies of vertebrae animals. 

Class

A biological classification of the levels of a group of animals according to their ancestral or hereditary hierarchy. There are over 100 classes of animals. 

Cloaca

An opening at the end of the posterior of animals that serves as the opening tract for reproductive, digestive, and urinary systems. 

Cloven-hoofed

The hoof of animals that appear to be split into two.

Clutch

A group of eggs laid and incubated together by a female bird. 

Cnidarian

A phylum of aquatic animals that live in marine habitats. 

Cocoon

A nest made of woven silk that houses the pupae or eggs of insects. 

Cold-blooded

Animals that cannot regulate their body temperature and absorb heat from the environment. 

Colony

A group of insects that live and work together in a nest while protecting and working with a queen

Complete Metamorphosis

The development stage in the life of insects which sees its development from egg, larvae, pupa, to adult. The egg differs in great detail from the adult. 

Compound Eye

The eye of an animal that is divided into different sections, each with its own lens. It is commonly found in arthropods. 

Conservation

The protection and preservation of species of animals with the intention of increasing their numbers and ensuring their continual survival. 

Conservation Status 

An indicator of the likelihood of species of animals being extant in the future.

The most recognized conservation status is the International Union for Conservation of Nature (IUCN) conservation status. 

Species are ranked in 9 categories, namely:

  • Not Evaluated
  • Data Deficient
  • Least Concerned
  • Near Threatened
  • Vulnerable
  • Endangered
  • Critically Endangered
  • Extinct in the Wild
  • Extinct

Constrictor

A snake that kills prey by wrapping itself around its prey, while restricting blood flow to vital organs.  

Crepuscular

Animals that are active at dusks and dawns, i.e., twilight periods. 

Crocodilian

A biological family of reptiles that include crocodile, alligators, gharials, and caimans. 

Crustaceans

A group of marine animals characterized by jointed limbs and hard shells. 

Cryptic Colouration

The coloring of animals which they used to fuse with their environment or camouflage their presence.

D

Decapods

Crustaceans with ten limbs. 

Delayed Implantation

A period of delay where the embryo does not get implanted in the uterus. 

Deposit Feeder

Aquatic animals that feed on organic matter that have settled down on the bottom of the ocean. 

Detritivore

A scavenging animal that feeds on dead, decaying plants and animals. 

Detritus

Dead organic matter that contains tissues of animals and plants and fecal matter. 

Dewlap 

A flap of loose skin hanging from the neck of an animal. 

Diet

The nature of food consumed by animals.

Digit

An animal finger or toes. 

Distinctive Features

Unique characteristics of an animal. 

Diurnal

Animals that are active during the daytime and rest at night. 

Domesticated

Animals that live and are cared for by humans. 

Dorsal

Located near or towards the upper surface of an animal. 

Down

A layer of soft feathers that traps hair to keep animals such as penguins warm. 

Drone

A male bee with the sole task of mating with the queen. They do not work on the colony and lack the ability to sting.

E

Echinoderm

A phylum of marine invertebrates that are found on the ocean beds and are characterized by hard internal skeletons. 

Echolocation

A method of emitting calls used by animals to locate their position and preys by listening to the returns of the calls from objects around them. 

Ecological Niche

The ecological conditions of an ecosystem and how an animal adapts to and is influenced by such conditions. 

Ecosystem

A geographic location where microorganisms, plants, and animals thrive alongside the physical factors necessary for animals to thrive functioning as a unit. 

Ectoparasite

An animal that lives on the body of another animal while deriving nourishment from the blood of the animal.  

Ectothermic

Animals that produce little to no heat from internal physiological systems and rely on the environment to generate heat. 

Eft

The phase in the development of amphibians from larvae to adults where they dwell mostly on land. 

Egg-sac

A bag made of woven silk formed by a female spider to house and protect her eggs. 

Egg-tooth

The temporary tooth of an infant spider that it uses to pierce through the egg sac after hatching. 

Elytra

A hard protective case that covers the fore wings and rear wings of insects. 

Embryo 

The early stage of development of multicellular organisms. 

Endangered

A conservation status level which points to a species of animal on the verge of being extinct. 

Endoparasite

An animal that lives in the tissues or organs of other animals and derives nourishment from it. 

Endothermic

Warm-blooded animals that can generate and regulate their body temperature. 

Equid

Animals that are members of the horse family. 

Environment 

The condition in which an animal thrives in. It refers to the physical and social conditions an organism lives in and how the animal interacts with other animals and living organisms in its surroundings.  

Estrus 

The period of sexual cycle in animals marked by release of reproductive hormones which makes them in heat and make them ready to mate. 

Estuary

A marine habitat where river freshwater and ocean saltwater meet. 

Estimated Population Size

The number of individuals of a particular species that exist at a particular period. 

Evolution 

The process of changes in heritable characteristics of an organism over time. 

Exoskeleton 

Skeleton of an animal located outside of the body. 

Extinction

The terminations of the existence of a species of organism. It is marked by the demise or death of the last individual of a species of animal. 

External Fertilisation

A form of reproduction in animal where the male sperm is introduced to the female egg outside the body.

F

Family

A taxonomic rank in the biological classification of animals which is between the order and genus taxonomic ranks. 

Fangs

Long, pointed tooth in animals used for tearing flesh, biting prey, and injecting venoms in some animals.  

Favorite Food

Preferred foods consumed by animals. 

Felidae

A biological classification of animals that are generally referred to as cats and are in the order Carnivora. 

Femur

The thigh bones in vertebrates with four legs. 

Feral

Animals that are domestically raised but now live in the wild. 

Fertilization

The process that occurs when a male animal’s sperm fuses with the egg of a female animal resulting in the development of a new organism. 

Fetus

The unborn offspring of an animal that develops from the embryo. 

Filter Feeder

Animals that are capable of extracting organic food matter out of water. 

Fish

Cold-blooded aquatic vertebrate animals that possess gills but do not have limbs.

They are mostly members of the biological class Actinopterygii. 

There are over 34,000 species of fish. Fishes serve as food for mammals, reptiles, and humans. 

Fledgling

A young bird that has developed feathers. 

Flightless

Birds with feathers but lack the ability to fly such as Emus and Penguins. 

Flight Feathers

The feathers of a bird that provides strength for power when flying. 

Flipper

The paddle-like limb of some aquatic animals which is used for swimming. 

Flanks

The flesh between the last rib and the hip on the side of an animal. 

Flock

A group of sheep or birds of the same species flying, feeding, or resting together. 

Flukes

Parasitic organisms (flatworms) found in the internal organisms of vertebrates and mollusks. 

Food Chain 

A linear sequence of links in an ecosystem that depicts the hierarchy of how food is consumed in the ecosystem.

The food chain begins with the producer organisms (plants that utilize sunlight to produce food through photosynthesis).

Producer organisms are consumed by the primary consumers (animals that feed on plants).

Secondary consumers feed on primary consumers and are then consumed by tertiary consumers.

Depending on the length of the food chain the tertiary consumers may be prey to the top predators or apex predators who are known as the quaternary consumers.

Food chains do not always end with the apex consumers but with the quaternary consumers who can be detritivores or species that feed on a decomposed matter such as fungi or bacterias. 

Food Web 

An interconnection of various food chains in the ecosystem. 

Forage

Plant organic matter fed upon by animals. 

Formic Acid

A colorless irritating chemical substance squirted by ants as a defense mechanism when they feel threatened. 

Fossil 

The remains, impressions, or traces of remains of an animal that was last of geological age. 

Frugivorous

Animals that feed majorly on raw food or succulent parts of plants such as roots, shoots, nuts, and seeds.

G

Gastropod

A biological class of invertebrates that are in the phylum mollusca. They are primarily snails and slugs. 

Genus

A taxonomic rank used in classifying living organisms found between the family and the species ranks. Names assigned at the genus taxonomic ranks forms the first part of an animal’s binomial or scientific name. 

Gestation 

The process where animals develop in the womb. 

Gestation Period 

The time or period between conception, development of the embryo in the womb, and birth of the animal. It differs in animals. 

Gill

The respiratory organ in aquatic animals which extracts oxygen in water and releases carbon dioxide. 

Gill Rakers

Bony or cartilaginous processes on the Gill arch that diverts solid matter from the gills.  

Gland

A group of cells in an animal’s body that produce and synthesises substances known as hormones which are released into the bloodstream, cavities or other parts of the body. 

Grazing

The act of feeding on vegetation in the wild.  

Group

Sets of animals that are classified together based on mutual characteristics. 

Group Behavior 

The actions animals engage in when associated with other animals mostly of its kind. 

Grub 

The larvae of insects such as beetles, wasps, and bees.

H

Habitat

The ecological term refers to the particular area where an animal thrives as well as the various resources, biopics, and physical factors present in such areas. 

Halteres

The knob-like or small cub-like organs found on the body of flying insects that aids their ability to fly. 

Heat Pit

A sensory organ located on the heads of snakes, which helps them detect heat given off by warm-blooded prey. It helps snake strike prey with precise accuracy in the dark.

Herbivore 

Animals that majorly feed on plants. 

Hermaphrodite

Animals that possess both male and females sexual organs and can reproduce on their own. 

Herpetology

The study of amphibians and reptiles. 

Hexapod

Arthropods that have six legs. 

Hibernation 

A state in which animals go to sleep for a long time or periods marked by long inactivity in order to survive cold periods. It is marked by low breathing, low heart rate, and low body temperature. 

Home Range

An area habited by a particular animal and where it moves to periodically. 

Hominids

A biological family of primates known as great apes which include humans and their evolutionary ancestors. 

Honey Guides

  • A bird found in the genus Prodotiscus that intentionally lead humans to bee colonies so as to feed on grubs and beeswax left behind. Also known as honey birds or Indicator birds. 
  • Markings on flowers that guide insects to nectars. 

Honeydew

A sugary sticky liquid secreted by insects that feed on plant saps.  

Horn

A permanent pointed projection that contains keratin, proteins similar to a live bone on the heads of certain animals. 

Host

An animal in which a parasite live or thrives in.

I

Incisor Tooth

The flat tooth is located in the front teeth of animals ls used for slicing or gnawing food. 

Incomplete Metamorphosis

The sort of development of an insect’s egg that sees it develop from the larvae stage directly to the adult stage but in a smaller size. The insect grows to full size as it develops. 

Incubate 

The act of keeping the eggs of animals warm until they are ready to be hatched. 

Incubation Period 

  • The time it takes from an animal’s exposure to a pathogenic organism to the time the effects or symptoms become apparent. 
  • It also refers to the period when an egg is laid to when it hatches. 

Insects

Invertebrate arthropods that belong to the phylum Insecta with bodies made of shells rather than bones.

They are characterized by an exoskeleton made of chitin, compound eyes, a three-part body (head, thorax, abdomen), and a pair of antennae.

Insects form about 90% of life on earth, and there are over 30 million species of insects. 

Insectivore 

Carnivorous animals that feed on insects. 

Instar

The developmental stage in insects between two molts before they reach sexual maturity. 

Internal Fertilization 

Fertilization that occurs inside the body and begins with the introduction of male sperm in the female reproductive organs. 

Introduced Species

Species of animals living and thriving in an area that is not their native range but were brought in accidentally or intentionally by humans.

It is also known as immigrant species, alien species, exotic species, foreign species, non-native species, and non-indigenous species. 

Invertebrates 

Animals that do not have vertebral columns or backbones. 

Invertebrates include all animals except mammals, reptiles, bony fish, and birds. Invertebrates form about 97% of animal species in existence. 

Ivory 

A white substance made of dentine that is found on the tusks or teeth of animals such as elephants and walrus.

J

Jacobson’s Organ

An organ found in the upper section of the mouth of some amphibians, reptiles, and mammals which serve as chemoreceptors and is part of the olfactory system of such animals. It is also known as the vomeronasal organ. 

Juvenile

Animals that are not yet adults.

K

Keel

An extension of the bird’s breastbone that keeps the muscles tight when flying. 

Keratin

Fibrous protein which animals’ horns, fingers, and nails are made of. 

Kingdom

The second highest taxonomic rank divided further into phyla. 

Krill

Small crustaceans that live in the ocean.

L

Lagomorph

Animals that are part of the Lagomorpha taxonomic order(rabbit and hare family) 

Larvae 

The early stage of an animal in which it is totally different from the adult form of such animals. 

Lepospondyls

An extinct group of early tetrapods. 

Lifespan

The length of an animal’s life. 

Litter Size

The number of young ones an animal can birth at a single time. 

Location

The geographical area in which an animal can be found.

M

Maggot

The larva of a fly. 

Mammal

A warm-blooded vertebrae animal that gives birth to its young ones alive. Mammals are part of the biological class Mammalia.

They are characterized by the presence of mammary glands for milk production for their young ones, possession of fur or hair, having neocortex in the brain, and the presence of three middle bones.

As recently as 2018, it has been revealed that there are as many as 6,495 species of mammals which includes 96 extinct species.  

Mandible

The lower jaws or jawbones of humans and other animals. 

Melon

Mass of fatty tissue found in the forehead of toothed whales that acts as a sound lens and helps their vocalization. 

Marine 

Relating to water habitats with salt concentrations. 

Marsupial

Animals that are members of the mammal biological class Marsupialia characterized by giving birth to undeveloped young ones who complete development in their mother’s pouch. 

Matriarch

The female leader of a group of animals. 

Maturity

A stage in the development of animals where they can breed. 

Maxillae

The upper jaw bones of animals. 

Metabolic Rate

The amount of energy an animal’s body expends while at rest. 

Metabolism 

The various chemical reactions that occur in the body of animals that result in the conversion of food into energy and the production of wastes. 

Metacarpal 

The set of bones found in the hands and limbs of four-limbed vertebrates. 

Metamorphosis 

Series of changes an animal undergoes as it develops to adulthood. 

Metatarsal 

Bones that are located in the back of the legs of vertebrates with four limbs. 

Midnight Zone

The dark part of the ocean, below the twilight zone. 

Migration 

Movement of animals covering large distances on a seasonal basis. 

Mimicry

The act engaged in by animals to camouflage their true identity to appear as other animals or objects in a bid to attract prey or evade predators. 

Molar Tooth

Flat ridged teeth located at the rear of a mammal’s set of teeth used for crushing and grinding food. 

Mollusk

A group of invertebrate animals that live in marine and terrestrial habitats and are known for their soft bodies and hard shells. There are about 85,000 species of mollusks in existence. 

Monogamous

Mating with a single partner for a lifetime or throughout the mating season. 

Monoestrous

Animals that experience estrus once in a year or animals that engage in breeding once in a year. 

Monotreme

Mammals that lay eggs. 

Molt

Shed skin, feathers, scales, and furs by animals. 

Mucus

The sticky, slimy liquid produced by the lining tissues in animals for protection or sticking on surfaces. 

Mustelids

Carnivorous mammals that belong to the Mustelidae family (otter family)

Muzzle

Nose and jaws of animals.

N

Name of Young

The name given to the offspring of an animal. 

Natural Environment

The terrain, range, and habitat of an animal in which it thrives. It comprises the living and nonliving factors in the habitat that affect the animal and its development. 

Natural Selection 

The process which involves the adaptation and changes in the population of living organisms over time. It refers to the increased presence of traits that give living organisms increased chances of surviving to reproduce in a population over different generations. 

New World 

The Western Hemisphere, i.e., the Americas.  

New World Monkeys

Five families of primates that reside in tropical regions in Mexico, South America, and Central America. They are generally called Ceboidea. 

Nectar

A sweet liquid produced by plants that attract insects for pollination. 

Neurotoxin

Harmful venoms produced by animals such as ants, spiders, and snakes capable of damaging and destroying the central nervous system or peripheral nervous system of animals. 

Niche

The role played by an animal in its habitat. 

Nocturnal

Animals that sleep during the day and are active during the night.  

Nudibranchs

Marine mollusks that shed their shell after the larval stage. They are called sea slugs and are related to land slugs. 

Nuptial Pad

A secondary sex characteristic present in animals such as salamanders and frogs. It appears on the forearms of animals and is used to grasp females during amplexus. 

Number of Species 

The number of recorded species of animals. 

Nymph

A young insect that appears to have an adult form but does not have the functioning organ that makes it capable of flying.

O

Offspring 

The young ones birthed by an animal. 

Old World

Africa, Asia, and Europe.

Old World Monkey

Family of primates that belong to the biological family Cercopithecidae. It is the largest primate family as it is made of 24 genera and 138 species. 

Omnivore 

Animals that eat both plants and animals. 

Operculum

Bones in fish which provide facial support and serve as a protective covering for the gill. 

Opportunists

Animals that feed on any organic matter they find. 

Opposable

Digits that can be pressed in opposite directions. 

Optimum pH Level

The ideal acid level for animals. 

Order

A taxonomic rank into which animals are classified. The order comes after the class and is sub-divided into families. 

Organ

Internal structure in animals made up of tissues that perform specific functions vital to animals’ well-being. 

Organism

Refers to living things that are single-celled or multi-celled. 

Origin

The area where an animal was initially found. 

Ornithologist

A scientist who studies bird and their behavior. 

Other names

Names given to animals that differ from their scientific and generally accepted names. 

Osteoderm

Bony deposits on the skin of reptiles and amphibians that protect them from predators. 

Oviparous

Animals that lay eggs with little or no embryonic development in mothers. It is a form of reproduction found in fishes, amphibians, and some reptiles. 

Ovipositor

An organ in insects in the form of a tube with which female insects lay eggs.

P

Parasite

An animal that lives inside or on the body of another animal and derives nourishment from the animal. 

Parthenogenesis

A form of asexual reproduction in which the embryo grows and develops without sperm fertilization. 

Paratoid Gland

Salivary glands found in animals. It is located in the mouths of animals. For amphibians, it is found in the eyes with which they use to shoot out venoms. 

Partial Migration 

A type of migration where some animals do not migrate with the rest of the herd. 

Pectoral

The front section of the body or front limbs. 

Pectoral Fin

Fin located on the side of fishes which is responsible for directional movements. 

Pedipalps

The second pair of appendages located in the first pair of walking legs in arthropods. 

Pelagic

A section of the ocean which is not near the bottom and not near the surface. 

Pelvic fin

Paired fins that are located on the underside of fishes. 

Pheromone

A chemical produced by animals that triggers a social response in other animals of its species. 

Phylum

A major taxonomic rank that classifies living organisms. It is found between the kingdom and class taxonomic ranks. 

Phytoplankton

Tiny plants that are part of the plankton community. 

Pigment 

A substance that gives color to animal eggs and feathers. 

Pinna

The external ear part of animals. 

Pinniped

A group of aquatic animals with flippers or fin feet. 

Placental 

Animals that their young ones develop in the placenta and are born fully developed. 

Plankton

Living organisms in marine habitats that cannot move against current or wind. They are an important source of food for both small and large aquatic animals. 

Plastron

The lower part of the shell of turtles and tortoises. 

Plumage 

The feathers of a bird. 

Pod

The collective noun for a group of dolphins or whales. 

Pollen

Tiny yellowish grain transported to other parts of plants by winds, insects, or animals and is responsible for fertilization. 

Pollinator

An animal that transports pollen from flower to flower while feeding on nectar. 

Polygamous 

Mating structure in animals where a single member of one gender mates with several members of another gender in a breeding season. 

Polygynous

Mating structure in animals where a single male mates with different females in a breeding season 

Polyp

Small animals with rings, tentacles, and stalk-like bodies that are closely related to jellyfish. 

Predator

Animals, usually carnivores, that hunt and kill other animals for food. 

Preening

The act of cleaning feathers carried by birds and oils from their preen glands. 

Prehensile

Body parts in animals that are capable of grasping. 

Premolar

Teeth found in mammals between the canine and molar used for slicing through flesh. 

Prey

An animal that is hunted killed, and fed on by other animals. 

Primate

An order of mammals that have five fingers for grasping things. 

Proboscidea

An order of mammals with African origins that consists of just one living family (Elephant family) and multiple extinct families. 

Proboscis

A long appendage from the head of animals or a tubular mouth used for sucking and feeding by animals. 

Prolegs

The fleshy legs of a caterpillar or similar-looking insect larvae. 

Protozoo

Animals that have one cell that feeds on organic matter. 

Pupa

The intermediate stage between the larvae and adult development in the metamorphosis of insects.

Q

Quadrupedal

Animals that walk on four limbs. 

Queen

  • The only female insect that lays eggs in colonies of ants, bees, and wasps. 
  • The term for a female animal of certain species.

R

Rainforest

A habitat near the equator that is characterized by tree canopies, lianas and epiphytes, ever-green vegetation, and no wildfire. 

Raptor

Birds of prey.

Regurgitate

The act of bringing out food that has been swallowed in order to feed young ones. 

Reproduction

The biological process that leads to the development of a new organ referred to as offspring from parents. 

Reptiles

Cold-blooded vertebrates that belong to the class Reptilia and are characterized by scaly skin and laying eggs on land. As of March 2022, the Reptile Database reports that there are 11,820 species of reptiles in the world.  

Roost

The home where birds gather to rest at night or the act of resting. 

Respiration

The biological process where oxygen is absorbed from the environment and supplied to an animal’s cells and tissues, with carbon dioxide being released to the environment. 

Ruminant

Hoofed herbivorous animals with specialized stomach chambers capable of breaking down plants. 

Rut

The period when animals such as sheep and ungulates engage in sexual activity.

S

Saprophagous

Animals that feed on dead, decaying, or decomposing animals and plants. 

Scales

Flat plate matter made of keratin which covers the body of animals for protection. 

Scavenge

The act of feeding and consuming dead animals that have died from natural causes. 

Scientific Name

The biological name given to a species by scientists. It is also called binomial nomenclature. 

School

A group of fishes that swim and move together. 

Scutes

Scales laden with horns or bony external plates that form hard shells. 

Sedentary

A lifestyle of animals that involves little movement. 

Sensory Hairs

Tiny hairs that connect to the nerves of insects that help them detect touch and different odors. 

Sessile

Animals that attach themselves to another object or animal and cannot move independently. 

Sett

The burrow or den of a badger. 

Sexual Dimorphism

The condition where different characteristics are exhibited by the sexes of the same species.

Silk

Fibrous proteinous material produced by spiders. 

Simple Eyes

Eyes that contain one lens and no elaborate retina. 

Size

The length and height of an animal. 

Sirenians

A group or order of aquatic herbivorous mammals. 

Skeleton

The structural framework of an animal that supports its body. 

Skin

The protective outer layer of an animal. 

Sloughing

The act of shedding old skin.

Spawn

Eggs of amphibians floating on water. 

Species

The basic unit of classification of living organisms or groups of organisms in which two organisms of different genders can produce fertile offspring.

Spermatophore

A mass containing spermatozoa produced by amphibians during reproduction. 

Spinneret

An organ located at the end of a spider’s abdomen where silk is produced. 

Spiracles

Small holes on the side of insects that are used for breathing. 

Spur

Small remnants of back legs found on Boa snakes. 

Sternum

The chest bone in the center rates that have grout limbs. 

Sting

A sharp point found at the end of certain animals with which they strike prey and infuse venoms in prey. 

Sounder

A group of pigs. 

Subspecies

A group of animals of the same species that live in different geographical locations. 

Syrinx

A sound-producing organ in birds located at the point where the windpipe connects with the pipes that lead to the lungs.

T

Tadpole

The larvae stage in the development of an amphibian. 

Temnospondyl

Amphibians that have developed to spend all their time on land. 

Temperament

The behavior and thinking pattern of an animal. 

Terrestrial

Animals that spend all their time entirely on land. 

Territorial

The act of defending an area that contains an animal’s nest, den, or mating site and is abundant with food from other animals. 

Territory

An area defended by an animal where it lives. 

Tetrapods

Vertebrate animals with four legs. 

Thermoreceptor

Nerves made of a sensory cell that detects heat. 

Thorax

The middle section of an insect body.  

Tibia

The bones in the shin of animals. 

Timbal

Structures that look like drums located on the legs of insects with which they make mating sounds. 

Trilobite

A group of marine arthropods that belong to the class Trilobita that are now extinct. 

Tissue

A layer of cells in animals that make up organs. 

Trachea

A pipe-like organ in animals that is part of the respiratory system of animals. 

Tusk

The bony extended front teeth of elephants. 

Twilight Zone

The part of the ocean that is dimly lit.

U

Underfur

The layer of fur that is closer to an animal’s body and keeps it warm. 

Uterus

An organ that is part of the female reproductive system in animals where offspring develop. 

Ungulate

Large mammals with a hoof.

V

Valve

One half of a hinged shell of a mollusk. 

Velvet

The skin that covers the antlers of animals. 

Venom

A harmful substance produced by animals that can alter the function of an animal’s body. 

Venomous

Animals that produce venoms. 

Vertebrae

The small bones that interlock to define the backbone. 

Vertebrate

A group of animals that cut across various classes of animals such as mammals, aves, reptiles, and amphibians, that are characterized by the presence of backbone in their body. There are about 69,963 species of vertebrates. 

Viviparous

Animals that give birth to live young ones.

W

Warm blood 

The ability of animals to maintain warm body temperature despite the temperature of their environment.  

Waterfowl 

Birds with webbed feet that live near water bodies.

Weaning 

The process of introducing young animals to the diet they would consume as adults while withdrawing milk from them. 

Web

A structure made of silk produced by spiders. 

Webbing

Skin flaps found between the legs of animals. 

Wing case

The tough, fore wing that covers the functioning wings of some insects. 

Wing span

The distance between the tip of one bird’s wing to the tip of the opposite wing. 

Worker

A member of an insect colony that constructs nests, finds food and cares for the young in the colony.

X

Xylophagous

Animals that feed or bite into wood.

Y

Yolk

A yellowish substance found in the eggs of animals that provide nourishment for their young ones.

Z

Zooplankton

Small aquatic microorganisms that are part of the plankton community.