The characteristics of animal-like protists, or protozoans, include the need to obtain food from their environment since they cannot make it themselves, and an ability to move around in their environment to obtain that food. As protists, they are all single-celled organisms that have nuclei and other membrane-bound organelles.
Protozoans are classified by the way they move and live. Some protozoans can change their shape very flexibly, and move by extending a part of their bodies, known as a pseudopod, forward, then pulling the rest of their bodies along. They also use pseudopods to reach out and capture food. Amoebas are part of this group of animal-like protists.
Another group of animal-like protists are those that move using cilia. Cilia are multiple small, hair-like structures lining the cell membrane which move the cell along as if they were oars on a boat. They also possess a pellicle, a thin layer that supports the cell membrane and gives the cell a definite shape. Pellicles vary in stiffness between species, but all are at least somewhat flexible. A paramecium is an example of this type.
The third type of motion in animal-like protists is the use of a flagellum. This is a long, whiplike structure that pushes the cell along. Many of these types of cells live in the bodies of other organisms, either as helpers or parasites.