  It is known that the contribution of torsion to the equation for the chiral
Weyl fermions can be equivalently considered in terms of the axial $U(1)$ gauge
field. In this scenario the gravitational field transforms to the $U(1)$ gauge
field. Here we show that in chiral superconductors the opposite scenario takes
place: the electromagnetic $U(1)$ field serves as the spin connection for the
Bogoliubov fermionic quasiparticles. As a result the electromagnetic field
gives rise to the gravitational anomaly, which contains the extra factor $1/3$
in the corresponding Adler-Bell-Jackiw equation as compared with the
conventional chiral anomaly. We also consider the gravitational anomaly
produced in neutral Weyl superfluids by the analog of the gravitational
instanton, the process of creation and annihilation of the 3D topological
objects -- hopfions. The gravitational instanton leads to creation of the
chiral charge.
