original: the only known communal roost contained only four individuals .
simplifications: only communal known contained roost four individuals . the only known communal roost contained four individuals . the only known communal roost had only four people . the sole communal roost had four people in it . the only known communal roost contained four individuals . the only known communal roost contained only four individuals . the only known shared place to stay had only four people . the only known communal roost contained only 4 individuals .