Sheep

are of different varieties. Probably the flocks of Abraham and
Isaac were of the wild species found still in the mountain
regions of Persia and Kurdistan. After the Exodus, and as a
result of intercourse with surrounding nations, other species
were no doubt introduced into the herds of the people of Israel.
They are frequently mentioned in Scripture. The care of a
shepherd over his flock is referred to as illustrating God's
care over his people (Ps. 23:1, 2; 74:1; 77:20; Isa. 40:11;
53:6; John 10:1-5, 7-16).

"The sheep of Israel are longer in the head than ours, and
have tails from 5 inches broad at the narrowest part to 15
inches at the widest, the weight being in proportion, and
ranging generally from 10 to 14 lbs., but sometimes extending to
30 lbs. The tails are indeed huge masses of fat" (Geikie's Holy
Land, etc.). The tail was no doubt the "rump" so frequently
referred to in the Levitical sacrifices (Ex. 29:22; Lev. 3:9;
7:3; 9:19). Sheep-shearing was generally an occasion of great
festivity (Gen. 31:19; 38:12, 13; 1 Sam. 25:4-8, 36; 2 Sam.
13:23-28).