The Earth is home to many creatures. Animals have been the inhabitants of this planet, along with humans. Historically, animals were used for transportation, protection, as well as for hunting. Animals have been companions to man since time immemorial. Animals are the kingdom while classifying their species. There are a variety of species present under this, with their presence spanning across the world. Amphibians primarily require a moist environment as they breathe and absorb through thin skins. Some amphibians include frogs, salamanders, toads, and caecilians. Mammals are vertebrates and warm-blooded. Females have mammary glands to feed their young ones and have a thick coat of fur. Mammals include carnivores, bears, rodents, etc. Reptiles are vertebrates, but lay eggs. Some of them have scales. Common reptiles are lizards, turtles, and snakes.Insects have an exoskeleton. They have three pairs of legs, a head, thorax, and abdomen. Beetles, ants, and bees are some insects. Birds have wings, beaks, and feathers such as eagles, pigeons, crows, and sparrows. There are many species of animals that are domesticated as well, such as dogs, cats, rabbits, horses, etc.Animals are vital to the ecosystem. Animals have different purposes when it comes to the environment. Even microorganisms help to clean our planet. Many animals aide plants to converting free nitrogen present in the air and nourishing the roots and a crucial role in sustaining ecological balance. Predatory animals keep the population in the animal population controlled. Animals that feed on plants help to control plant growth. They also provide us with the food required for our survival. Poultry, dairy, and meat serve as essentials to many cultures and their diets. Animals are one of the oldest companions of humans.However, many species face the threat of extinction. Urbanization causes cutting down forests to meet the needs of the growing human population. Cutting down forests has led to a loss of habitat for many animals. Habitat destruction has caused damage to animal life. Lions and bears traditionally hunted for their fur, elephants for their ivory tusks, and alligators for leather sell in black markets. Torturing animals and locking them in cages affects their wellbeing. Dumping effluents into water bodies affect marine life. Global warming also affects animals, with dried up water bodies and seasonal changes that have consequences on these species. Using animals to test human-made drugs has received widespread criticism as the animals suffer irreparable damages.The importance of conserving animals has been recognized all over the world. International organizations such as the PETA and World Wide Fund for Nature (WWF) aim to spread awareness on preservation. Countries have strict laws for animal conservation. The Indian government has many wildlife protection projects such as Project Tiger and Project Elephant, animals whose populations are decreasing drastically.