  Long-range dipole-dipole and quadrupole-quadrupole interactions between pairs
of Rydberg atoms are calculated perturbatively for calcium, strontium and
ytterbium within the Coulomb approximation. Quantum defects, obtained by
fitting existing laser spectroscopic data, are provided for all $S$, $P$, $D$
and $F$ series of strontium and for the $^3P_2$ series of calcium. The results
show qualitative differences with the alkali metal atoms, including
isotropically attractive interactions of the strontium $^1S_0$ states and a
greater rarity of F\"orster resonances. Only two such resonances are
identified, both in triplet series of strontium. The angular dependence of the
long range interaction is briefly discussed.
