What are those strings that hang from the pants of Jewish men and boys?

I see it’s nearing to Friday, and yet, my curiosity can’t wait.

While riding through a Jewish neighborhood, I saw several boys walking together, and all of them had strings hanging from (what I would assume are) the belt loops of the pants. The strings were a light brown color.
What was this I saw? What does it mean?

Sorry for asking so close to Friday.

IANA ;j , but if I recall correctly, those tassels are trailing from a small garment worn underneath the shirt, which is something akin to a poncho. I think it’s only worn by Hasidic Jews, but I could be wrong.

On preview and a minute of research, I’m pretty close [scroll about halfway down].

They are the fringes of tallit.

The fringes are called tzitzit, and they are attached to a tallit (actually, to a tallit katan, which refers to a little shawl. A tallit is a four-cornered garment worn during prayer services with fringes tied to it, as a reminder of the mitzvot, the commandments. A tallit katan is a small, four-cornered shawl with fringes at the corners worn under clothing all day, as an opportunity to exemplify this commandment during the whole day.

The tallit, or prayer shawl, is worn by conservative and orthodox Jewish males at morning prayer services. (I think it’s optional or varies with Reform.) It’s like a shawl, although some can be quite large, with tassels/fringes at each corner, based on Numbers 15:37-41 (and other biblical references)

Many orthodox and most hasidic Jews also wear a smaller such shawl (sort of like a poncho) underneath their outer garments, called a tallit katan (small tallit), and the fringes of this tallit katan are what you might see dangling out from under their shirts.