In Temecula- saw a small mammal, maybe 50% longer than a chipmunk. Similar coloring to a gray squirrel but not at all bushy. More like slightly furry, almost hairy. Behavior similar to a squirrel - sort of skittish. Was it the California version of our midwestern gray squirrel?
Was it on the ground? Were there burrows? It could have been a ground squirrel. Anything here look familiar? Trees are not a necessary part of their environment.
The Western Grey Squirrel looks like this. Tree squirrels spend some time on the ground, but prefer trees for safety and nesting.
Very broad answer, but I hope this helps.
I don’t know what a mid-western squirrel is, but around here in L.A. parks and running along all the telephone lines I think are mostly the smaller eastern grey squirrels. (That’s probably what the OP saw.) The California grey squirrel itself is not as prevalent as the transplanted eastern one.
if its a desert squirrel… thell eat anything thats planted … we have one that used to like to raid my aunts pumpkins … since the neighbors behind us dont have dogs … hell be back this year …
In the Midwest I think for tree squirrels it would be the eastern gray squirrel, the fox squirrel( Sciurus carolinensis and S. niger, respectively ) and the American red squirrel( Tamasciurus hudsonicus ).
In the LA area and CA in general I believe the fox squirrel is far and away the mostly widely distributed introduced species. You can find introduced eastern grays in California as well, but they are much patchier in distribution. GG Park in SF is one major stronghold.