You can search for charities by 'cause.' For example, the Humane Society is categorized within the “Animals” cause. In some cases an organization’s work may apply to multiple causes. For example, the American Red Cross is categorized in both Health Care and Disaster Relief.
A nonprofit's cause area is automatically determined by its NTEE code(s). Often, the organization's cause was determined at the time of their original request for tax exempt status, and it could be out of date. If you feel that your organization is categorized incorrectly, please open a support ticket.
For more information about NTEE codes (National Taxonomy of Exempt Entities), visit this page: https://learn.guidestar.org/help/ntee-codes