Facts About All Zombies

Witch_Doctor

How People Turn

They are bitten by an infected person.
In general the turning takes place quickly - within 30 seconds to 2 minutes; the exception is that turning may take much longer or even prevented by unknown causes.
Transmission is still unclear however based on given clues, infection appears to be through fluid exchange via spit or blood contact into the blood stream. A Tower residents journal revealed that fluid to undamaged skin contact had no affect.
Early in the story Riley says that she and Pegs witnessed people being attacked and may come in contact with infected blood and turned.
According to Tanya, some victims are Slow Turners, in that an infected victim can take days or weeks to turn into a zombie.

How the Zombies Can Tell Where People Are

Certain zombies have an acute sense of hearing, however some are deaf but have a good sense of smell.
Attracted to the smell of pheromones and human blood.
Their sense of smell can be thrown off by chemicals with a strong scent, ie perfume, alcohol.
Alcohol seems to repell zombies.

Notable Facts

Zombies rest and/or sleep.
The zombies are cannibals.
Animals cannot turn.
Zombies can build a tolerance to homemade chloroform within minutes.
Some zombies take more than one bullet to bring down.
The zombies in L.A. carry their dead and deceased victims back the the Arena where they are either eaten or burned or both.
Not all zombies retrieve their dead as the L.A. zombies do. This fact is stated by Victor, near the Colony.
Not all zombies use the the Arena as a home base. Some prefer to live on an island, etc.
In general Zombies (especially regulars) hunt or roam in packs; but smaller numbers or single Zombies are encountered as well in almost any region.
Although some Zombies or groups of Zombies are encountered during the daytime, only a few days after the outbreak the higher threat from Zombies is during the night.
Clear distinction between zombies that lead and zombies that follow.
Burt mentioned that he believes that the smarter you were in life, the smarter you are as a zombie.
Based on the descriptions from the main characters journals, the "zombies" are all described as having some sort of deformity or super human strength or ability.
Uncertain whether zombies are actually dead. Necessity of food and sleep points otherwise.
According to Tanya Zombies need food and air as normal living beings.