You can pick and choose your Safari search engine. Popular choices include Bing, DuckDuckGo, Google, and Yahoo. You can change this in settings, but there’s also a quick keyboard shortcut.
[macOS 10.13.4: Sorting Safari Bookmarks by Name]
Change Safari Search Engine
If you want to change your search engine, open a new tab and press the Spacebar in the empty URL field. This gives you an option to change the search engine, but also gives you a list of recent searches.