2004). B-lymphocytes, the cells that produce antibodies, are initially produced in the embryonic liver, yolk sac and bone marrow, then move through the blood to the bursa of Fabricius (BF). Birds have a bursa of Fabricius (BF), which is an outpocketing of cloaca.
Most squirrels are vegetarians. There are a few exceptions like the flying squirrel. The flying squirrel will eat small birds, insects and definitely steal eggs from birds nest in order to make a meal. Generally speaking though, squirrels will mainly stick to things that are vegetarian related.
Rock squirrels live in rocky terrain, such as. canyons and hillsides, but also are well-adapted to. suburban and urban areas. Seeds, nuts and berries are important food items for. rock squirrels. Their diet can be very diverse. They will. feed on acorns, pine nuts, juniper berries, mesquite buds. and fruit from cactus. During the spring and early. summer, rock squirrels also feed on green vegetation, such as grass, forbs and flowers.