  We study the shadows of the fully non-linear, asymptotically flat
Einstein-dilaton-Gauss-Bonnet (EdGB) black holes (BHs), for both static and
rotating solutions. We find that, in all cases, these shadows are smaller than
for comparable Kerr BHs, i.e. with the same total mass and angular momentum
under similar observation conditions. In order to compare both cases we provide
quantitative shadow parameters, observing in particular that the differences in
the shadows mean radii are never larger than the percent level. Therefore,
generically, EdGB BHs cannot be excluded by (near future) shadow observations
alone. On the theoretical side, we find no clear signature of some exotic
features of EdGB BHs on the corresponding shadows, such as the regions of
negative (Komar, say) energy density outside the horizon. We speculate that
this is due to the fact that the Komar energy interior to the light rings (or
more precisely, the surfaces of constant radial coordinate that intersect the
light rings in the equatorial plane) is always smaller than the ADM mass, and
consequently the corresponding shadows are smaller than those of comparable
Kerr BHs. The analysis herein provides a clear example that it is the light
ring impact parameter, rather than its "size", that determines a BH shadow.
