New Dog?

On April 3rd we were at a dog park at 63rd and Northern (Dad Elyse And I). We saw a very scrawny dog. We sat by a bench and gave her all the treats that we had brought for Coco. And about the whole time her tail was between her legs. After about 20 minutes she had warmed up to us. She quickly climbed up the stairs and laid down. Then we went and sat down with her. So we called my mom and she took Coco home and dad,Elyse and I to Annie to Petco and check to see if she was chipped. She was not. So we took her home and went on a website to see if any one had put her on the website. So right now we are keeping her by our pool area. If nobody claims her by May we get to keep her.