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Animals / Wildlife: Most Popular Articles

These articles are the most popular over the last month.
The Big 6: The Basic Animal Groups
An introduction to the six basic groups of animals including amphibians, birds, fishes, invertebrates, mammals, and reptiles.
The 10 Largest Living Mammals
A list of the largest species in each group of mammals that inhabit our planet today.
Animal Profiles: An A to Z List By Scientific...
An A to Z list of animal profiles available in The Animal Encyclopedia, sorted alphabetically by scientific name.
Animal Profiles: An A to Z List By Common Name
An A to Z list of animal profiles available in The Animal Encyclopedia, sorted alphabetically by common name.
Top 10 Wildlife Conservation Organizations
A list of my top ten favorite conservation organizations that work to protect animals and wildlife around the world.
Give A Hoot: Learn 10 Fantastic Facts About Owls
Facts about owls, a group of birds known for their distinct calls, nocturnal habits, and silent flight.
Mammal Profiles - An A to Z List of Mammals
The following is an A to Z list of mammal profiles available, sorted alphabetically.
10 Simple Things You Can Do to Protect Animals
A list of simple things you can do to help protect animals and wildlife.
What Defines an Endangered Species?
Definition of endangered species, a term used to refer to a species in danger of extinction throughout all or a significant portion of its range.
What's the Difference Between Prokaryote and...
All living organisms can be sorted into one of two groups depending on the fundamental structure of their cells. These two groups are the prokaryotes and the eukaryotes.
10 Cool North American Animals
A list of some of the animals that inhabit North America including the nine-banded armadillo, tufted titmouse, caribou, monarch butterfly, and more.
Lion Pictures
Lions are the largest of all African cats. They are the second largest cat species worldwide, smaller than only the tiger. Lions range in color from nearly white to tawny yellow, ash brown, ochre, and deep orange-brown. They have a tuft of dark fur at the tip of their tail.
10 Curious Creatures from the Amazon River Basin
A list of ten animals of the Amazon River basin in South America including harpy eagles, three-toed sloths, toucans, and more.
Basic Mammal Groups - Guide to Animal...
An introduction to the basic mammal groups including aardvarks, bats, carnivores, cetaceans, elephants, marsupials, primates, rodents, and many others.
Lions, Tigers, Leopards, Cheetahs and Other Cats
In this photographic guide, find out more about cats, their classification, adaptations, and natural history.
The 8 Key Characteristics of Mammals
Learn about the key characteristics of mammals including mammary glands, hair, endothermy, diphyodonty, and more.
Turtle Tidbits: What Do Turtles Eat?
Turtle eating habits are varied--what they eat depends on the available food sources, the habitat in which the turtle lives and the turtle's behavior.
Beyond the Arms: 11 Facts about Octopi:
From clouds of ink to chromatophores, there's more to octopi than eight arms.
What Makes an Animal an Animal?
Learn about the key characteristics of animals including multicellularity, eukaryotic cells, sexual reproduction, movement, and more.
North and South American Cats
Pumas, also known as mountain lions, catamonts, panthers or cougars, are a large cat whose former range extended from coast to coast across North America. By 1960, they were declared extinct in most midwestern and eastern ranges. Page 7.
Arthropods: Centipedes, Millipedes, Spiders,...
Profile of arthropods, a group of invertebrates that includes insects, spiders, crustaceans, scorpions, centipedes, and many others.
Cool Facts About Bears
Facts about bears, a group of carnivores known for their burly build, impressive agility and, in some species, their winter sleep habits.
Facts You Should Know About Birds
Facts about birds, a group of vertebrates that includes nearly 10,000 species that are unique for their feathers and furculas, also know as wishbones.
How a Pride of Lions Operates
Definition of lion pride, a term that refers to a group of line that typically includes about five females and two males and their young.
10 Little-Known Facts About Giraffes
Facts about giraffes, a group of mammals that are best known for their tall profile, long neck, and the distinct patchwork pattern of their fur.
What Is Evolution? The Fossil Record, Natural...
A brief overview of the history of life from the time the first life evolved until the present day. Page 2.
7 Kinds of Animals Found at the Great Barrier...
A list of some of the animals that inhabit the Great Barrier Reef including sea birds, mollusks, marine mammals, marine reptiles, and more.
How Many Animal Species Are There on Earth?
An article examining how scientists estimate and count the number of animals that live on our planet today.
Why Mammals Are Amazing
Profile of mammal, a group of four-legged vertebrates that have hair, a four chambered heart and mammary glands.
Top 10 Cute Birds
Of all animals, birds are among the most varied in color, shape and size. In this gallery we'll catch a glimpse of a small handful of the many birds that can claim to be the cutest of their kind.
What You Probably Don’t Know About Dolphins
Learn interesting facts about dolphins and find out about the characteristics make them different from other animal groups, their life cycle and their evolutionary history.
10 Facts About Jellyfish
Learn interesting facts about jellyfish and find out about the characteristics make them different from other cnidarian groups, their life cycle and their evolutionary history.
What Life Is Like for a Jellyfish
The most recognized image of a jellyfish is that of the adult jellyfish, with its bell-shaped body and long tentacles.
Do You Know What an Echinoderm Is?
Profile of echinoderms, a diverse group of marine invertebrates comprising approximately 6000 species.
What You Should Know About Molluscs
Profile of molluscs, a group of invertebrates that includes squid, octopuses, cuttlefish, nudibranchs, snails, slugs, limpets, mussels, and many more.
The Basic Invertebrate Groups
An introduction to six basic groups of invertebrates including arthropods, cnidarians, echinoderms, mollusks, segmented worms, and sponges.
Fact Sheet: Carnivores - Racoons, Fur Seals,...
Profile of carnivores, a group of mammals that includes dogs and their relatives, bears, racoons, mustelids, civits, hyenas, aardwolf, and cats.
What's a Cnidarian?
Cnidarians are diverse and come in many shapes and sizes but there are some basic features of their anatomy that most members of the group share in common.
Reptile Characteristics
What is a reptile? To answer this question, we must understand the characteristics of reptiles - such as amniotic eggs, scales and ectothermy.
Why Habitat Destruction Is So Harmful
Definition of habitat destruction, a term that is used to describe the process by which natural habitat is damaged or destroyed.
Fast Facts About Mammals
Learn interesting facts about mammals and find out about their diversity, evolutionary history and the characteristics make them different from other animal groups.
Endangered Animals
Endangered animals are species or populations that are at risk of becoming extinct.
Why Insects Are Fascinating
Profile of insects, a highly successful group of animals that accounts for more species of animals than any other class of animals.
Can You Define “Species”?
The term species can be defined as a group of individual organisms that are capable of interbreeding to produce fertile offspring in nature.
What You Probably Don’t Know About Reptiles
Learn interesting facts about reptiles and find out about their diversity, evolutionary history and the characteristics make them different from other animal groups.
Learn About the Stages in a Frog's Life
The life cycle of a frog consists of three stages: egg, larva, and adult. As the frog grows it moves through these stages in a process known as metamorphosis. Page 4.
Great Facts About Great Horned Owls
Learn interesting facts about great horned owls and find out about the characteristics make them different from other animal groups, their life cycle and their evolutionary history.
Vertebrates Versus Invertebrates
One criteria by which all animals are described is whether or not they have a backbone. This article explores facts about vertebrates and invertebrates.
Why Keystone Species Are So Important
A keystone species is a species that plays a critical role in maintaining the structure of an ecological community and whose impact on the community is greater than would be expected based on its relative abundance or total biomass.
The Basics of Vertebrate Evolution
An overview of vertebrate evolution that explores the key developments in the evolution of mammals, birds, reptiles, amphibians, and fish.
Learn the Basics About Birds
Birds are vertebrates that have four limbs, wings, feathers, hollow bones and other adaptations for an aerial lifestyle.
Reptiles - Reptilia - The Animal Encyclopedia
Profile of reptiles, a group of vertebrates that colonized terrestrial habitats more extensively than their amphibian ancestors.
Get the Facts on Marsupials
Learn interesting facts about marsupials and find out about the characteristics make them different from other animal groups, their life cycle and their evolutionary history.
Learn Your Basic Amphibian Groups
An introduction to the three basic groups of amphibians including salamanders and newts, caecilians, and frogs and toads.
Animals: Arthropods, Chordates, Molluscs,...
Profile of animals, multicellular organisms that are capable of locomotion and that rely on other organisms to obtain their nourishment.
Fast Facts About Amphibians
Learn facts about frogs and find out about their diversity, evolutionary history and the characteristics make them different from other vertebrates.
Fast Facts About Invertebrates
Learn interesting facts about invertebrates and find out about their diversity, evolutionary history and the characteristics make them different from other animal groups.
What’s a Chordate? You’re a Chordate
Profile of chordate, a group of animals that includes vertebrates, tunicates, lancelets.
Classification of Cats
Cats belong to the group of vertebrates known as mammals. Within the mammals cats are classified with other meat eaters in the Order Carnivora (known commonly as 'carnivores'). Page 3.
30 Groups of Birdies: The Basic Bird Groups
An introduction to the 30 basic groups of birds including birds of prey, buttonquails, gamebirds, herons, hummingbirds, owls, rheas, and many others.
Fast Facts About Frogs
Learn interesting facts about frogs and find out about their diversity, evolutionary history and the characteristics make them different from other amphibian groups.
Things You Probably Don’t Know About Zebras
Facts about zebras, a group of equids with a distinct black and white striping pattern.
Learn About Lions
Profile of the lion, a species of large cat that has a buff colored coat, white underparts, and a long tail that ends in a black tuft of fur.
Cats of Africa - Caracal, Serval, Cheetah,...
The cats of Africa include the caracal, serval, cheetah, lion, and leopard. Page 8.
Bats
Bats are the worlds only group of mammals that have wings. This profile explores basic facts about bats including how they are classified, what they eat, where they live and the characteristics that make them different from other mammal groups.
Sponges: Glass Sponges, Demosponges, and...
Profile of sponges, a group of simple aquatic invertebrates that include glass sponges, demisponges, and calcareous sponges.
Vipers
Profile of vipers, a group of snakes that include true vipers, bush vipers, rattlesnakes, pit vipers, adders and night adders.
Cats
Cats inhabit a wide variety of habitats including coasts, deserts, forests, grasslands, and mountains.
How to Choose the Right Binoculars
A guide to the different kinds of binoculars and their many features. Page 2.
How Vertebrates Moved Out of the Oceans
The vertebrates that underwent the evolutionary transition from life in water to life on land faced four basic adaptive challenges
10 Interesting Facts About Arthropods
In this article, you'll learn interesting facts about arthropods and find out about their unique characteristics, their life cycle and their evolutionary history.
The Largest Organisms on Earth
Giant sequoias, blue whales, Komodo dragons. Find out more about these and other sizable creatures in this article.
10 Interesting Facts About Molluscs
Molluscs are invertebrates that include animals such as squid, octopuses, cuttlefish, nudibranchs, snails, slugs, limpets, sea hares, mussels, clams, oysters, scallops, as well as many lesser known creatures.
How Waves and Tides Work
Waves give rhythm to the ocean. They transport energy over vast distances. Where they make landfall, waves help to sculpt a unique and dynamic mosaic of coastal habitats.
Learn Your Animal Facts
Learn interesting facts about animals and find out about the characteristics make them different from other groups of living organisms.
Threatened Species
A threatened species is a native species that is at risk of becoming endangered in the near future.
Learn the Basic Reptile Groups
An introduction to the four basic groups of reptiles including crocodilians, lizards, snakes and turtles.
Cartilaginous Fish - Chondrichthyes - The...
Profile of cartilaginous fishes, a group of fishes that includes the largest and most formidable marine predators alive today -- sharks.
Lion Portrait
Lions are the largest of all African cats. They are the second largest cat species worldwide, smaller than only the tiger.
What Is Descent with Modification?
Descent with modification refers to the passing on of traits from parent organisms to their offspring.
Get Educated About Amphibians
Profile of amphibians, a group of vertebrates that includes frogs and toads, caecilians, and newts and salamanders.
Organ Systems in Animals
Animals' bodies are made up of various organ systems, groups of organs that work together to perform a function.
Elephant Trunk
Elephants' trunks are muscular, flexible extensions of their upper lip and nose. The tip of an African elephant's trunk has two fingerlike growths that enables them to grasp food and other small objects.
Why Males and Females Look Different
Sexual dimorphism is the difference in form between male and female members of the same species.
What Makes a Bird a Bird?
Bird characteristics include numerous adaptations for flight such as feathers, a furcula and hollow bones. This article explores the key characteristics that together distinguish birds from other animal groups.
Tiger Pictures
Tigers are the largest and most powerful of all cats. They are extremely agile despite their bulk and can leap between 8 and 10 meters in a single bound. They are also among the most recognizable of cats thanks to their distinct orange coat, black stripes and white markings.
Why You’re a Heterotroph
A heterotroph is an organism that is unable to obtain its carbon from carbon dioxide. Instead, heterotrophs obtain carbon from organic material such as other organisms, living or dead.
What Is an Invertebrate?
Definition of invertebrate, an animal that lacks a backbone. Invertebrates account for more than 97% of all species alive today.
Fact Sheet: Mouse-Like Rodents - Hamsters,...
Profile of mouse-like rodents, a group of rodents that includes rats, mice, voles, hamsters, lemmings, dormice, harvest mice, muskrats, and gerbils.
The Biggest Threats to Animals and Wildlife
Living things face a constant barrage of external stresses or threats that challenge their ability to survive and reproduce. If a species is unable to successfully cope with these threats through adaptation, they may face extinction.
How Animals Interact with Their Environment
A first step to understanding individual animals, and in turn populations of animals, is to understand the relationship they have with their environment.
Why Species Have Niches
Definition of a niche, a term used to describe the role an organism or population plays within its community or ecosystem.
Learn Your Fish Groups
An introduction to the basic fish groups including bony fishes and cartilaginous fishes.
Bony Fishes: Ray-Finned Fishes and Lobe-Finned...
Profile of bony fishes, a group of vertebrates characterized by having a bony skeleton unlike the cartilaginous fishes whose skeleton consists of cartilage.
Understanding Population Biology
Populations are groups of individuals belonging to the same species that live in a shared region at the same time.
What to Know About Elephants
Profile of elephants, a group of mammals that are noted for their large size, massive skull, and long muscular trunk.
Florida Panther Pictures
Pictures of Florida panthers, an endangered subspecies of panther that scientists believe are healthier and fitter than they were fifteen years ago. They have higher genetic diversity, better immunity to disease, and fewer genetic abnormalities. They suffer fewer heart defects, enjoy higher fertility and are better able to climb trees.
The Crazy Things Reptiles Eat
What reptiles eat differs from species to species but here you'll find out about some of the general dietary trends within the four subgroups of reptiles.
Endangered Species FAQs
Endangered species are species that face a significant risk of extinction. Such species may be declining in number due to things such as habitat destruction, climate change, threats from invasive species.
Fast Facts About Fish
Learn interesting facts about fishes and find out about their diversity, evolutionary history and the characteristics make them different from other animal groups.
What’s a Deciduous Forest?
Profile of the deciduous forest, a type of forest in which the trees shed their leaves during the cold months of the year.
What Is Desertification?
Desertification is the development of desert-like conditions in regions that have experienced human disturbance such as deforestation, overgrazing, or poorly managed agriculture.
Reptile Pictures
Pictures of reptiles, including reptile photos such as anoles, chamelons, geckos, alligators, turtles, snakes and more.
World Wildlife Fund
The World Wildlife Fund (WWF) is a global-scale conservation organization that works in 100 countries and consists of nearly 5 million members worldwide.
Interesting Facts About Snowy Owls
Learn interesting facts about snowy owls and find out about the characteristics make them different from other owls, their life cycle and their evolutionary history.
Owl Pictures
Pictures of owls, including owl photos such as snowy owls, northern saw whet owls, great horned owls, barn owls and more.
Mammal Pictures
Pictures of mammals, including mammal photos such as pronghorn, meerkats lions, koalas, hippopotamuses, dolphins and more.
What You Should Know About Jellyfish
Profile of jellyfish, a group of carnivorous cnidarians with a bell-shaped body and tentacles.
Animal Profiles from A to Z
The following is an A to Z list of animal profiles available, sorted by animal group.
Defining Zoology
Zoology is the study of animals; yet this definition implies a simplicity that does not exist; instead, zoology is a complex discipline, drawing upon a diverse body of scientific observation and theory.
What to Know About Tigers
Profile of tigers, the largest and most powerful of all cats that have a distinct orange coat, black stripes and white markings.
Animal Pictures - An A to Z List of Animal Photos
The following is an A to Z list of animal pictures available at this site, sorted alphabetically by common name.
American Beaver
Profile of the American beaver, one of two living species of beavers and the world's second largest rodent, only the capybara of South America is larger.
Monotremes
Monotremes are a group of mammals that include echidnas and the platypus. This profile explores basic facts about monotremes including how they are classified, what they eat, where they live and the characteristics that make them different from other mammal groups.
Perching Birds: Wagtails, Swallows, Crowas,...
Profile of perching birds, a group of birds known for their specialized feet and the complex vocalizations and songs.
The Parts of a Feather
Feathers are a unique adaptation of birds. Feathers are made up of keratin, an insoluble protein that is also found in mammalian hair and reptilian scales.
Learn About Appalachian Mountain Habitat
Profile of the Appalachian Mountain Range, an ancient band of mountains that stretches in a southwestern arc from Newfoundland to Alabama.
About Cheetahs, Lynxes, Caracal and Other Small...
The Subfamily Felinae, or the small cats, are a diverse group of carnivores. Page 4.
How Communities and Ecosystems Interact
The natural world is characterized by many complex interactions. Individuals belong, in turn, to populations, species, communities, and ecosystems.
What You Should Know About African Elephants
Profile of the African elephant, the largest living land mammal and one three species of elephants alive today.
Primates: Lemurs, Lorises, Galagos, Monkeys,...
Primates form a diverse group of mammals that includes about 233 species that are grouped into 13 families.
The Nature Conservancy
Profile of The Nature Conservancy, a conservation group that works with governments, communities, and others to solve conservation challenges.
Learn About Tasmanian devils, Numbats,...
Marsupials are a group of mammals that give birth to their young at an early stage of their development.
Snow Leopard Pictures
Snow leopards are mountain-dwelling cats that live throughout the ranges of South and Central Asia at altitudes between 9,800 and 16,500 feet. Snow leopards are classified as endangered and their population is declining due to habitat destruction and a dwindling prey base.
Learn About Babirusas, Pigs, Warthogs, and More
Hogs and pigs, also known as suids, are a group of mammals that includes babirusas, pigs, warthogs, forest hogs, red river pigs, and bushpigs. The Family Suidae also includes the domestic pig, Sus scrofa. The Family Suidae is subdivided into eight genera containing a total of sixteen species of pigs.
Facts About Carnivores
Learn interesting facts about carnivores and find out about the characteristics make them different from other mammals, their life cycle and their evolutionary history.
Guide to Terrestrial Snails
Snails start life as an egg buried in a nest a few centimeters below the surface of the ground. Page 6 of 14 Guide to Terrestrial Snails
Invertebrate Pictures
Pictures of invertebrates including horseshoe crabs, jellyfish, ladybugs, snails, spiders, octopus, chambered nautiluses, mantises, and more.
Invertebrates: The Animal Kingdom's Spineless...
Profile of invertebrates, animals that do not have a backbone or a bony skeleton.
Amphibian Pictures
Pictures of amphibians including red-eyed tree frogs, axolotl, green tree frogs, California newts, leopard frogs, and more.
Plankton
Plankton are microscopic organisms that drift on the oceans' currents. They include organisms such as diatoms, dinoflagillates, krill, and copepods as well as the microscopic larva of crustaceans, sea urchins, and fish.
Fact Sheet: Rodents - Kangaroo Rats, Gophers,...
Profile of rodents, a group of mammals that includes squirrels, dormice, mice, rats, gerbils, beavers, gophers, kangaroo rats, pocket mice, and many others.
Natural Resources Defense Council
The Natural Resources Defense Council (NRDC) is an environmental action organization that consists of 350 lawyers, scientists, and other professionals and commands a membership of about 1.3 million people.
Turtles: From Side-Necked Turtles to Hidden-Nec...
Profile of turtles, a group of reptiles best known for the hard shell which is a modification of their ribcage and vertebral column.
Ostrich Pictures
The ostrich is the tallest and heaviest species of all living birds. Although its bulky body means that flying is out of the question, the ostrich has adapted to life on the ground with impressive agility.
Fun Facts About Some of Earth's Weirdest Animals
Profile of armadillos, sloths, and anteaters, a group of mammals that are notable for the unique joints in their backbone.
Aquatic Biome: Tropical Reefs, Brackish...
Profile of the aquatic biome, a biome that consists of habitats around the world that are dominated by water--from tropical reefs, to brackish mangroves, to Arctic lakes.
Bird
A bird is an animal that belongs to the Class Aves.
Learn About the Arctic Wolf
Profile of the Arctic wolf, a subspecies of grey wolf that lives in the Canadian Arctic, Alaska, and northern Greenland.
American Black Bear: One of North America's...
Profile of the American black bear, a large carnivore that inhabits the forests, swamps, tundra throughout the more northerly reaches of North America.
Leopard
Profile of the leopard, a large cat that has a pale, cream-yellow coat with solid black spots.
Hares and Pikas - Lagomorpha - The Animal...
This profile explores basic facts about hares, rabbits and pike including how they are classified, what they eat, where they live and the characteristics that make them different from other mammal groups.
Bird Pictures
Pictures of birds including vultures, puffins, jays, cranes, sandgrouse, robins, gannets, plovers and more.
Pigeons and Doves
This profile explores basic facts about pigeons and doves including how they are classified, what they eat, where they live and the characteristics that make them different from other bird groups.
Even-Toed Hoofed Mammals - Artiodactyla - The...
Even-toed hoofed mammals include 225 species.
Why Do Fireflies Glow?
Fireflies, also known as lightning bugs, glow to lure prey, discourage predators, and most importantly to attract mates.
Polar Bear
The polar bear is among the largest land carnivores, comparable in size only to the brown bear. Polar bears weigh in the range of 400kg-680kg (880lb-1500lb) and are 2.1m-3.3m (7ft-11ft) in length.
Newts and Salamanders: Long-Tailed, Slender-Bod...
Profile of newts and salamanders, slender bodied amphibians with a long tail and usually two pairs of limbs.
The Biomes of the World - Animals and Wildlife...
Biomes are large regions of the earth that share similar characteristics such as climate, soils, precipitation, plants, and animals.
The Wild Side of Animal Senses
Man-made radars and infrared detectors help humans to stretch beyond the five senses. However, animals had these extra senses first. Read about all of them.
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