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Over 1.5 million living animal species have been described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77 million animal species on Earth. Animal body lengths range from 8.5 μm (0.00033 in) to 33.6 m (110 ft).
Training a puppy? Here's when they're able to learn key skills. Read. Animals. Why do octopus punch fish? Science has a compelling theory. Read.
Explore amazing facts, photos, and videos of your favorite animals with National Geographic Kids. Join the fun and learn more about the natural world.
- Overview
- The animal kingdom
Animals are multicellular eukaryotes whose cells are bound together by collagen. Animals dominate human conceptions of life on Earth because of their size, diversity, abundance, and mobility. The presence of muscles and mobility is one of the primary characteristics of the animal kingdom.
What are the two major groups of animals?
The two major groups of animals are vertebrates and invertebrates. Vertebrates have backbones, and invertebrates do not.
When did animals first appear?
Animals first appeared in the Ediacaran Period, about 635 million to 541 million years ago, as soft-bodied forms that left traces of their bodies in shallow-water sediments.
What are the basic functional systems of animals?
Animals evolved from unicellular eukaryotes. The presence of a nuclear membrane in eukaryotes permits separation of the two phases of protein synthesis: transcription (copying) of deoxyribonucleic acid (DNA) in the nucleus and translation (decoding) of the message into protein in the cytoplasm. Compared to the structure of the bacterial cell, this ...
Explore the diversity and wonder of animals with pictures, videos, facts, news, and more from National Geographic. Learn about amphibians, birds, fish, invertebrates, mammals, reptiles, and more.
Welcome to Animalia, an online animal encyclopedia where you can learn about all your favourite animals, and even some you may have never heard of.
Explore the world of animals with facts, images, definitions, diagrams and more. Learn about mammals, birds, reptiles, fish, amphibians, insects and invertebrates from different countries and regions.
