While lions are considered vulnerable, tigers are the odd one out as they are the only ones actually endangered; there are estimated to be less than 3500 tigers remaining in the wild.
Threats to tigers include destruction of their habitat for timber and agriculture and fragmentation of their habitat by the building of roads, competition with humans where they are forced to live close together, and - above all else - poaching. Tiger parts are used in traditional medicines and make popular trophies.
(I did research to get that answer!)