The fracton dynamics of percolating Heisenberg antiferromagnets are st
udied in terms of a dynamic scaling argument and large-scale numerical
analysis. It is shown that the spectral (or fracton) dimension for an
tiferromagnetic fractons, ($) over tilde d(AF), is bounded by the rela
tion ($) over tilde d(AF)less than or equal to 1. The densities of sta
tes (DOS) are calculated for very large percolating antiferromagnets a
t the critical concentration p(c) formed on d=2, 3, and 4 simple cubic
lattices. It is concluded, from the calculated DOS's, that the spectr
al dimensions ($) over tilde d(AF) are very close to unity for any Euc
lidean dimension d(greater than or equal to 2). We have also calculate
d the DOS for percolating antiferromagnets above p(c) in order to clar
ify the crossover behavior from extended magnons to fractons. In addit
ion, the dynamical structure factor S(q, omega) is investigated both a
nalytically and numerically. It is found, postulating a single-length
scaling, that the asymptotic behaviors can be characterized by two exp
onents, the dynamical exponent Z(AF) and a new exponent y. The numeric
al results for S(q, omega) support the validity of the single-length-s
cale postulate.