* Studying fossils: Fossils are the preserved remains or traces of animals, plants, and other organisms from the past. Paleontologists collect fossils from rocks and sediments and study them to learn about the animals that produced them. Fossils can provide information about an animal's size, shape, diet, and behavior.
* Comparing living and extinct animals: Paleontologists also compare living animals to extinct animals to learn about how they evolved. By studying the similarities and differences between living and extinct animals, paleontologists can infer the evolutionary relationships between different species.
* Using molecular biology: Molecular biology is the study of the structure and function of molecules, such as DNA and proteins. Paleontologists can use molecular biology to extract DNA from fossils and compare it to the DNA of living animals. This can help them to determine the evolutionary relationships between extinct and living animals.
* Using computer modeling: Paleontologists also use computer modeling to create simulations of extinct animals. These models can help paleontologists to visualize extinct animals and to understand how they moved and behaved.
By using these methods, paleontologists have been able to learn a great deal about extinct animals. They have discovered that extinct animals were a diverse group of creatures that lived in a variety of habitats around the world. They have also learned about the evolution of animals over time and the causes of extinction.