  Black holes in $d < 3$ spatial dimensions are studied from the perspective of
the corpuscular model of gravitation, in which black holes are described as
Bose-Einstein condensates of (virtual soft) gravitons. In particular, since the
energy of these gravitons should increase as the black hole evaporates,
eventually approaching the Planck scale, the lower dimensional cases could
provide important insight into the late stages and end of Hawking evaporation.
We show that the occupation number of gravitons in the condensate scales
holographically in all dimensions as $N_d \sim \left(L_d/\ell_{\rm
p}\right)^{d-1}$, where $L_d$ is the relevant length for the system in the
$(1+d)$-dimensional space-time. In particular, this analysis shows that black
holes cannot contain more than a few gravitons in $d=1$. Since dimensional
reduction is a common feature of many models of quantum gravity, this result
can shed light on the end of the Hawking evaporation. We also consider
$(1+1)$-dimensional cosmology in the context of corpuscular gravity, and show
that the Friedmann equation reproduces the expected holographic scaling as in
higher dimensions.
