• Baikal seal;
  • Phoca sibirica;
  • eye;
  • facial muscles;
  • macroscopic observation


This study was performed to determine if, as expected, the enlarged eye of the Baikal seal (Phoca sibirica) has an influence on the form and function of the skull and facial muscles. Macroscopic observation of these muscles demonstrated that the M. orbicularis oculi expands around the palpebral fissure and that some facial muscles attach and insert in the M. orbicularis oculi, possibly supporting M. orbicularis oculi function. We suggest that these muscles move the eye and palpebral area and constitute a morphological and synergistic facial muscle complex system. Further, the development of the M. rectus lateralis around the sclera of the eye indicates that this muscle is also involved in eye movement.