My next door neighbors are wildlife biologists, and have a few old weathered deer skulls in their garden as decoration.
As the skulls were right outside their front window, they noticed that the local squirrels were spending a fair bit of time chewing on the skulls.
When they mentioned this to me, I asked if I could have one for my NR Guro.
Here she is, happily munching away on the skull.
Guro is 22 months old, with extremely limited use of her right forelimb:
https://thesquirrelboard.com/forums/...Release-or-Not
Anyone else try deer skulls as a calcium source?
With Guro as well as various previous squirrels (youngsters being overwintered for release) I have never had much luck with beef or chicken bones, deer antler, shells, etc. So I am very encouraged to see (and hear) Guro gnawing at the skull.
I suspect that the thinness of the facial bones helps, as it is easy for squirrels to chew.