What are Vertebrates?

Vertebrates are animals which have a backbone. Vertebrates are divided into 5 classes: mammals, reptiles, amphibians, fish, birds, and arthropods.

The 5 Classes of Vertebrates

• Mammals
  • Mammals have hair and are vertebrates. Mammals are warm blooded, and most give birth to young.
    • Placentals include whales, armadillos, rodents, bats, humans, elephants, and other mammals. Placental mammals are complex animals. When they give birth, their babies are more complex than most babies of other animals.
    • Marsupials include kangaroos, koalas, opossums, wallabies, Tasmanian devils, and others. Marsupial mammals give birth when the baby is undeveloped. The baby stays in its mother’s pouch until it develops. All female marsupials have a pouch to carry their young.
    • Monotremes include four species of echidnas, and the duck billed platypus. Monotremes are only found in New Guinea and Australia. Monotremes are mammals that, unlike Marsupials and Placentals, lay eggs instead of giving birth.
• Reptiles
  •  Reptiles are cold blooded, and have hard, dry skin. They are oviparous, which means they do not give birth, but they lay eggs. Some species of reptiles lay eggs, then allow them to grow on their own. Others are very protective of their young.
    • Lizards are the largest group of reptiles. About four thousand, seven hundred sixty-five species of lizards have been discovered so far. Lizards have different strategies to catch prey and escape from predators. For example, chameleons use camouflage to sneak up on insects, then use their long, sticky tongues to snatch it up before it can even react! Gila Monsters use its colors to warn predators of its poison. Komodo Dragons are the largest lizards in the world. They can grow up to be nine and four fifths feet long and can weigh three hundred thirty pounds. Komodo Dragons are endangered, but also carnivorous. Their saliva is full  of bacteria that can kill their prey immediately with a bite.
    •  Crocodilians include crocodiles, alligators, caimans, gavials and caimans. Crocodiles and alligators seem the same, but they are very different. A crocodile’s head is more V-shaped , while an alligator’s head is more U-shaped. Also, alligators  are bluish-black while crocodiles are greenish-grey. Crocodiles are more ferocious than alligators. Crocodiles also prefer seawater and alligators prefer freshwater. Caimans are also similar, but have much narrower bodies than crocodiles and alligators and have wider and shorter heads. Gavials are strange-looking crocodilians with exceptionally long and narrow snouts.
    • Turtles can live on land, freshwater, and saltwater, but they lay their eggs on land. Almost all aquatic turtles are carnivorous like the Hawksbill Sea Turtle, which eats sponges (sponges are animals). Some turtles have claws instead of flippers. These are called tortoises.
    • Snakes are reptiles that have a different developed structure than other animals. Snakes have scaly skin and no legs. Some species of snakes are poisonous while others are not. If the snake has a big head and large body, it is usually venomous. If the snake has a small body and head, it is most likely not poisonous. Still, no matter how small it is, if you see a snake run the other direction.
• Amphibians
  • Amphibians are animals that can live in water and on land. They are tetrapods and vertebrates that spend half of their life on land, and the other half on water. Many species of amphibians are poisonous.
    • Aura amphibians include frogs and toads. First, frogs and toads start out as eggs. Then, those eggs hatch into tadpoles. Later that month, the tadpoles grow hind legs. After that, they grow hind legs, lose their tail, and become froglings, that grow into adult frogs. This process is called the life cycle of a frog. The differences of frogs and toads vary. Frogs have longer legs, for jumping great distances. Toads have shorter legs used for hopping. Frogs lay their eggs in clusters, while toads lay their eggs in chains. Toads also prefer land while frogs prefer water. Frogs prefer moist environment. Toads can live in moist environments but they usually prefer dry environments.
    • Gymnophiona amphibians include caecilians.  Caecilians, that can give birth or lay eggs, are unusual, snake-like amphibians that live underground. Caecilians can have eyes under their skin, or they don’t have them at all. Caecilians also have tentacles.
    • Urodela amphibians include salamanders and newts. The difference is that newts have dry, rough  skin. They prefer dry environments. Salamanders have damp skin and prefer moist environments. Salamanders and newts can either have lungs, gills, or both lungs and gills. Some salamanders breath through their skin, having no lungs or gills.
• Fish
  • Fish are animals designed for in the water. Most fish are cold blooded. Fish absorb oxygen from the water so they can breath. All fish have dorsal and anal fins to balance, pectoral and pelvic fins to steer, and caudal fins to move forward.
    • Bony fish have normal, fish-like bodies. They have skeletons, unlike cartilaginous fish. This class of fish is the largest class of vertebrates living today. Bony fish is further divided into ray-finned fish and lobe-finned fish.
    • Jawless fish don’t have jaws. Instead, they have rows of teeth in a round mouth called an oral disk. Most jawless fish have become extinct over the past five million years, although some survived extinction. Examples of these include lampreys.
    • Cartilaginous fish have a skeleton made of cartilage. Cartilaginous fish have gills like all fish. Cartilaginous fish have no bones, but they have teeth. Cartilaginous fish are divided into two groups.The Holocephali group include sharks, rays, sawfish, and skates. The Elasmobranchii group includes rabbit fish, elephant fish, and rat fish.
• Birds
  • Birds have either feather or fur. Most birds can fly, though not all. Some birds, like the humming bird, can hover. All birds have wings, claws or webbed feet, a beak, and a tail.
    • Raptors: These birds, also called birds of prey, hunt their food. Raptors have dangerous talons and a sharp beak to attach the prey, great eyesight to spot their prey, and many more fascinating features. These birds include Eagles, Vultures, Owls, Falcons, Harriers, Kites, and the Osprey.
    • Parrots: Parrots include Macaws, Cockatoos, Amazons, lovebirds, and lorikeets. Parrots have a curved beak and four toes. Two toes point in one direction while the other two point in the other direction. Parrots eat flowers, nuts, seeds, fruit, and arthropods like insects.
    • Land Birds: Not all birds can fly. Some birds prefer to run. The Ostrich is the world’s largest bird. It is also the fastest running bird in the world. Ostriches use their wings to steer when they run instead of to fly. They can sprint up to 43 miles per hour. Roadrunners also prefer to run instead of to fly, although they are not flightless like the Ostrich. Roadrunners are speedy birds. They are the fastest running birds in North America. These birds both have long legs to help them run.