It looks like there is no alternatve to wireshark or tshark. But never fear... An alternative is here!

On Ubuntu (ofcourse), you can install it via apt-get install tshark
Some examples:

tcpflow -i eth0 -c -e
With this one you'll see all the traffic for your network card. Add the -s parameter if you see too many gibberish passing by. It will convert non-printable traffic into periods.

tcpflow -i eth0 -c -e port 80
Only interested in datastreams to port 80, use the command above.

tcpflow -i eth0 -c -e host
if you're only interested in traffic from- or ment for

But there is more. If you do not use the -c switch, tcpflow will create for each datastream a separate file. Add the -b parameter and the files created can be limited in filesize. 

Do keep in mind that tcpflow is not in development anymore and it cannot handle fragmented ip packets.