The Hypermedia Bloodhound depends on libpcap, so if you are on linux, you need to install the package first (sudo apt-get install libpcap-dev), if you are on OSX 10.6+, you already have it.
We also depends on libgeoip for the IP address lookups, so sudo apt-get install libgeoip or brew install libgeoip on OSX.
$ npm install
$ sudo node bin/bloodhound
$ node bin/bloodhound --help