All wolves in a pack have a rank. This is different to what it would be in real life, but even so most packs are the same in this.
The ranks are named after the Greek alphabet, although there might be some difference in the order lower down in different packs, usually those whose leaders know no Greek! (*smirk* I can speak Greek!). Some packs also have extra ranks which are in italics.
There are two wolves to each station, a male and a female, usually mates. They are equal in rank. The way it works is complicated. Say that Mirror got promoted to Beta Male, but didn't have a mate. Rainfall wants Mirror's position, and is free to challenge him to fight for it. The winner gets the position. BUT, if Poison wanted the Beta Female position, but doesn't want to become Mirror's mate (not that there's anything wrong with Mirror, she just doesn't want to be his mate...yeah...) she CAN'T challenge the Beta Female position. But then Mirror gets together with Clarity, and Clarity becomes Beta Female. Now Poison can challenge Clarity. If Clarity wins the fight, she and Mirror keep their positions, and if Poison wins then Poison becomes Beta Female and Clarity and Mirror lose their places.
The simple way to get around this without confusion? Don't challenge anyone.
You must always obey those of a higher rank, especially the Alphas. If you yourself gain a high rank, remember that your wolf's station is above the others' and behave accordingly.
I've only added up to Eta, because some sites go all the way through the alphabet, others don't. Once you get nearer the bottom, there's really no point in differentiating between the ranks, as they're all pretty much on the same level anyway.
Please note that some packs have more ranks, or less ranks, or even no ranks at all. I have just put in the most common.
ALPHA - Usually one of them is the owner of the site. The other is their mate. This position cannot usually be challenged.
BETA - Second in command to the Alpha(s). This is the position that other wolves challenge the most, so Beta's need to be strong, and it helps if they choose strong mates.
HEAD HUNTERS - there are sometimes two of these, sometimes more. They organise the hunts.
PUP SITTER -there are more than two of these, and none of them have to be mates. They basically look after the pups in the pack.
WOLVES/ADULTS/OMEGAS - your general, run-of-the-mill wolves. They have no particular rank.
PUPS - wolves, usually born into the pack, who have not yet reached adulthood.