We implement Wilson fermions on 2d Lorentzian triangulation and determine the spectrum of the Dirac--Wilson operator. We compare it to the spectrum of the corresponding operator in the Euclidean background. We use fermionic particle to probe the fractal properties of Lorentzian gravity coupled to c=1/2 and c=4 matter. We numerically determine the scaling exponent of the mass gap M \sim N^-1/d_H to be d_H=2.11(5), and d_H=1.77(3) for c=1/2 and c=4, respectively.

PACS numbers: 04.20.Gz, 04.60.Kz, 04.60.Nc, 05.50.+q