Organisms that depend on other animals for survival are called parasites.

Here's a breakdown:

* Parasitism: A relationship where one organism (the parasite) benefits at the expense of another organism (the host). The parasite typically lives in or on the host, taking nutrients and resources, often harming the host in the process.

* Examples of parasites: Ticks, fleas, tapeworms, lice, some fungi, certain viruses, and even some plants like mistletoe.

Let me know if you'd like to learn more about specific types of parasites or their relationship with their hosts!