Between their first and third months of life, babies gain the skills to grasp and shake hand toys; they may even transfer them from one hand to the other. Like all developing motor skills, this improves with practice.
- Shelov, S. P. (Editor-in-Chief). (2004.) Caring for Your Baby and Young Child: Birth to Age 5. The American Association of Pediatrics. Revised edition. New York: Bantam Books.