Thestrals live in a variety of biomes, the most common being thick forest areas. They thrive off of dark, quiet environments where they aren't likely to be disturbed.  Some other common environments that Thestrals have been documented living in are caves, jungles, and swamps.

A herd of Thestrals can claim up to 10 miles of land, depending on the size of said herd. This land is fiercely protected by the males of the herd. Males have been known to fight to the death in order to protect their herd's land. Due to their docile nature, fights are rare, and Thestrals usually respect one another's boundaries.

By nature, Thestrals are more likely to flee from human intrusion rather than fight. When humans - both magical and non-magical - intrude upon a wild Thestral herd, they are likely to flee the area.