Mechanical arm and logistics robot

The mechanical arm comprises an arm body, a first paw and a second paw, the first paw is movably arranged on the arm body, a first protruding part is arranged at the end, away from the arm body, of the first paw, the second paw is movably arranged on the arm body, and a second protruding part is arranged at the end, away from the arm body, of the second paw. A second protruding part and a third protruding part are arranged at the end, away from the arm body, of the second paw, the protruding direction of the first protruding part faces the second protruding part, the protruding direction of the second protruding part faces the first protruding part, and the protruding direction of the third protruding part deviates from the second protruding part. The first paw and the second paw can move in the direction close to each other or away from each other so that the first paw and the second paw can clamp or loosen materials. The mechanical arm can grab and pull materials, the problem that in the prior art, the oper