There are an estimated 1-2 million species of animals in the world, although some sources place that number as high as 50 million. We will discuss how many animals have been found here—so without further ado, let’s get into the details!
Animals make up over 75% of all species on Earth, and fall into two categories: vertebrates and invertebrates. We can divide these two main groups further:
The class Mammalia consists of mammals, which are characterized by mammary glands that produce milk for nourishing their young; a neocortex and fur or hair.
Reptiles are air-breathing animals with distinctive skin comprised of scales, bony plates, or a combination of both. They all produce eggs that distinguish them from other cold-blooded species.
Amphibians are cold-blooded animals that spend their lives in both water and on land. They can live in either environment, unlike most other animals which require a certain type of habitat to survive
Amphibians are cold-blooded animals that spend their lives in both water and on land. They can live in either environment, unlike most other animals which require a certain type of habitat to survive
The term “invertebrates” refers to animals without backbones. More than 95% of all animal species worldwide are invertebrates, and they can survive in different environments depending on their lifestyles.
Birds are considered to be vertebrates since they have wings and feathers. The easiest way to differentiate between birds and the rest of the animals is their wings.
The number of known mammal species has increased significantly over the past two decades. From 1993 to 2005, it grew from 4,631 to 5,416; and now 6,495 new species have been identified.
Reptiles are one of the most diverse vertebrate groups on the planet. There have been over 10,700 extant species in the Reptile Database. Only birds and fish have more species than reptiles.