I reread the taxonomy in Leviticus 11, and while it starts off reasonable, it quickly becomes sketchy and careless.

It starts off by saying that big land animals that are OK to eat have divided hooves and chew the cud, but quickly makes mistakes about these.

Later on, it gives a list of birds that are no-nos, a list that includes the bat, and "four-legged" insects that are OK to eat. However, a bat clearly looks *much* more like a mouse than a "true" bird, and grasshoppers have six legs and not four. After paying close attention to the extremities of livestock animals, the writers of Leviticus had come sadly short.

Also, a lot of the translations are uncertain, it is not exactly clear which kinds of birds or orthopterans or lizards are being referred to; this is another sign of failing to continue with careful taxonomy. There isn't anything on how to identify owls or eagles or whatever.

I will conclude with doing a simple comparison of birds, bats, and mice. I'll ignore features shared by all three, for obvious reasons.

Body covering:
Bird: feathers
Bat: hair
Mouse: hair

Beak:
Bird: yes
Bat: no
Mouse: no

Teeth:
Bird: no
Bat: yes
Mouse: yes

External ears:
Bird: no
Bat: yes
Mouse: yes

Front limbs are wings:
Bird: yes
Bat: yes
Mouse: no

Resemblance scores (best = 5):
Bird - Bat: 1
Bird - Mouse: 0
Bat - Mouse: 4

From these easily observable features, the clear winner is bat - mouse.