Legislation, also known as proposed laws, is introduced every year or for a two year period, depending on the selected jurisdiction (state). The federal government and many states have a two-year "carryover" session that usually begins in the odd year (ie. 2013) and ends at the end of the even year (ie. 2014), though there are exceptions. Many other states have a session that runs through a single calendar year. Bills can be introduced any time during the session—though many states have a cut-off date for the introduction of new bills—but at the end of the session any bill not passed is "dead" and would have to be reintroduced as a new bill the next session. Below is a comprehensive selection of current legislation on a wide range of topics that concern animals.