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Do You Know?

There are many different animal classes and every animal in the world belongs to one of them. Most pets belong to the animal group vertebrate, which means they have a backbone, and includes amphibians, birds, fishes, mammals, and reptiles. Arachnids (spiders) and insects belong to the animal group arthropods, which are invertebrate, meaning they do not have a backbone.

Animals can be warm-blooded or cold-blooded. Warm-blooded animals are built to maintain just about the same temperature all of the time. Often fur and fat help protect warm-blooded animals from the cold, and sweating and panting help protect them from the heat. Cold-blooded animals are the same temperature of the air or water around them, and go into the water or shade to cool down, and lay in the sun to warm up.

• If an animal is born in the water, breathes with gills like fish at birth, and develops lungs and can live on land when they mature, then it is an amphibian. The meaning of the word "amphibian" is "two-lives", which is accurate for these critters, as they spend their lives in the water and on land. Amphibians are cold-blooded. There are more than 3,000 different kinds of amphibians, which include such animals as frogs, toads, salamanders, newts, and caecillians or blindworms.

• If an animal has feathers and is born out of hard-shelled eggs, then it is a bird. Feathers come in different types and do many jobs for birds. The soft down keeps them warm, wing feathers allow flight, tail feathers are used for steering, and the feather color can be used to hide the bird or to find a mate. Songbirds, hawks and eagles, ducks, geese, swans, herons are all part of the bird family.

• If an animal lives in water and has gills, scales, and fins on its body, then it is a fish. Most, but not all fish, are cold-blooded. According to scientists, there are more than 24,000 different species of fish in the world, ranging from the largest, Whale Shark at 51 feet long, to the smallest, Stout Infantfish at 1/4 inch long. There are fish with noses like elephants, blind fish, fish that crawl onto land and hop about, and fish that shoot down passing bugs with a stream of water, among many others. And, yes, a Seahorse is a fish!

• If an animal drinks milk when it is a baby and has hair on its body, then it is a mammal. There are about 4,000 kinds of mammals, including dogs, cats, horses, duckbill platypuses, kangaroos, dolphins, whales (and even people). Mammals are warm-blooded, allowing them to be very active and to live in a wide variety of places, and are found everywhere - polar bears live in very cold areas, camels live in hot areas, moles live under the ground, bats live in caves and fly in the air, dolphins live in the oceans.

• If an animal has scaly skin, is cold-blooded, and is born on land, then it is a reptile. Members of the reptile group include snakes, lizards, alligators and crocodiles, and turtles. The scales that protect their bodies can be hard or soft, large or small. Reptiles are born with strong instincts, and are on their own, right at birth.

• If an animal is invertebrate, has a segmented body, an exoskeleton, and has more than four jointed legs, then it is an arthropod. Insects, spiders, centipedes, mites, ticks, crustaceans, barnacles, scorpions, and many, many others, all belong to this class of critters. About 85% of all known animals in the world are part of this class. Arthropods are cold-blooded, are some of the most interesting animals in the world, they fly, creep, and crawl, and they live on land, in ponds, and in the ocean.