I haven't heard of them attacking humans in the wild but I recently read where one in a city had tried to get a small child. Thank goodness his big brother was out there too and saved the child. Here's a link to a article where a child was attacked.
http://origin.www.cbc.ca/canada/edmo...es-edmont.html
Any animal that is out of their natural area will have strange behavior. Out in the wild there are usually enough small animals that they're not a problem but in the suburban areas and the cities they are becoming problems.
They form packs but I'm not sure if they hunt in packs or not. Here's some information on coyotes. There's even a map that shows where they can be found. I hope that this answers your questions!
http://animals.nationalgeographic.co...ls/coyote.html