[TOMT][BOOK] Ant-like aliens control the world and fight bigfoot/sasquatch

My dad told me about this series(?) of books he read a LONG time ago where aliens that were sort of like super-smart ants had control over the world and would prevent humanity from progressing far in technology. He said they would stop humans from making advanced weapons by either removing the person who discovered them or by wiping humanity out at that point, I can't quite remember. Also, they were apparently enemies of creatures that were like bigfoot/sasquatch.

I'd love to find this series for him and surprise him with it, if anyone can help.