Animal Groups
Scientists like to organize things into groups. A long time ago, a Swedish scientist named Linnaeus organized all living things into groups that were alike. This page will give some information on his classifications that we still use today.
Although the classification system is VERY complicated, I will list some animals below by whether they have backbones/skeletons (vertebrates) and ones without (invertebrates).
The Invertebrates all have one thing in common: they have no skeleton on the inside of their body!
But, there were still many differences between them, so Linnaeus split them into more groups. He did the same with the vertebrates. Look below for more details. THIS LIST IS NOT COMPLETE, BUT A PARTIAL LIST OF ANIMALS!! There are too many to list here, so I have included the main ones.
Do a Google search on “Animal Classification,” and you will find more information.
Also, visit these websites:
Invertebrates – animals with no backbone
Echinoderms
Animals with spines radiating from their bodies: starfish and sea urchins
Annelids
Animals that have segmented, soft-bodies, some with short or long bristles: worms and leeches
Mollusks
Soft-bodied animals that may live on the land or in the water: octopus, snails and slugs, and oysters
Arthropods
Hard-shelled body/exoskeleton, segmented and jointed legs, this group includes: crustaceans, arachnids, and insects
Crustaceans
Hard-shelled, has a head and abdomen (2 body parts), antennae, jointed legs for walking, some have claws: lobster, crabs, shrimp, barnacles
Arachnids
Exoskeleton, no antennae, jointed legs: spiders (2 body parts and 8 legs), scorpians, ticks and mites
Insects
Exoskeleton, antennae, some with wings, 3 body parts (head, thorax, abdomen)
Vertebrates – animals with a backbone
Fish
Animals that live underwater and have gills to breathe: tuna, sharks, rays, goldfish, koi. This group includes bony fish that have scales, and some that have cartilage instead of bones (soft bone) and no scales (such as the sharks and rays).
Reptiles
Animals with scales all over their bodies, cold-blooded, and breathe air: turtles, snakes, and lizards
Amphibians
Animals with smooth and wet skin, cold-blooded, and lays eggs in the water. Amphibians spend the first part of their lives swimming in water like fish, with gills, then develop legs and lungs to be able to live part of the time on land: frogs, toads, and salamanders.
Birds
Animals that are warm-blooded, have feathers, and wings: penguins, ostrich, canary, and hummingbirds.
Mammals
Animals that are warm-blooded, feed their babies milk, have hair or fur (even if it is barely noticeable), and breathes air with lungs. There are several groups of mammals: rodents, primates, cetaceans, marsupials, and many more.
Rodents
Animals that have long, sharp teeth that continue to grow: mice, rats, hamsters, and squirrels…but NOT rabbits, rabbits are lagomorphs.
Lagomorphs
Rabbits, hares, and jackrabbits.
Primates
Animals that have well-developed hands and fingers including an opposable thumb, highly developed brains and vision, may walk on four legs but can walk on 2: monkeys, chimpanzees, gorillas, baboons, orangutans, and HUMANS! (yes, we are animals too).
Cetaceans
Ocean dwelling animals that have flippers/fins, but breathe air, and feed their babies milk. They may have sparse hair on their bodies: whales and dolphins.
Marsupials
Animals that give birth to under-developed babies and raise them in a pouch on their body. Kangaroos, opposums, koalas, and wombats.
