Stop the clicking

How can I get the cameras to stop clicking? For starters, it scares animals that I have caught on camera. Plus, I had someone come in my house that I didn’t know would be there and she heard the click and turned the camera so I couldn’t see what she was doing. If the only way to get the camera to stop clicking is to turn off night vision, that sort of defeats the purpose of having a camera or security doesn’t it?