Animals that may have shared the same habitat with Tsaagan include Protoceratops, Shuvuuia, the small mammal Zalambdalestes, the multituberculate mammal Kryptobaatar, as well as several lizards and two yet-undescribed species of troodontid and dromaeosaurid.
Among unenlagiines is one of the largest dromaeosaurids, Austroraptor (5.8 metres), as well as some of the smallest, Buitreraptor and Rahonavis.