Newly adopted dog ran into the forest at night and won’t come back—what now?

I accidentally let it out of the yard while I was doing something else, and he took off as fast as mortally possible and hit the trees and bushes about 500 feet behind the house. I tried calling him and whistling and clapping hands over and over to get his attention, but it's like he's deaf or something. He doesn't come to his name or other attempts to make friendly sounds nor get his attention. Now it has been 30 minutes and I doubt I'll ever catch the dog again, since it's dark now, and again he doesn't respond to verbal commands or anything else.

We adopted him about a month ago and had this problem twice during the daylight, but he eventually came back both times. I don't think I'll be able to catch him at night.

It's part rat terrier and part something else. I don't know. It's adopted.

Newly adopted dog ran into the forest at night and won’t come back—what now?
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