Gross Morphological Studies on the Vertebral Column of Indian Eagle Owl (Bubo bengalensis)

Abstract

Background: Indian eagle owl known to rotate their necks up to 270 degrees in either direction without injuring their vessels running below the head thereby without cutting off blood supply to their brains. The vertebral column in birds carry peculiar features like higher number of cervical vertebrae due to long mobile neck, lumbar and sacral vertebrae fused together giving rigidity which aid in flight. The extensive fusion of vertebral column posterior to the neck provides the required rigidity in the trunk region, this inflexibility feature might reduce weight, as it avoids the need for extensive musculature to maintain a streamlined and rigid body posture during flight. The current study aimed to study the vertebral column of Indian eagle owl in order to understand the anatomical adaptations related to this species. Methods: The specimens were procured from three Indian eagle owl brought for post mortem examination during the year 2019 to the Department of Veterinary Pathology, Rajiv Gandhi Institute of Veterinary Education and Research, Puducherry. After completion of the post-mortem examination the carcass was collected and macerated as per the standard technique and various measurements on vertebral column bones were measured using vernier calliper. Result: The study revealed that vertebral column of Indian eagle owl consisted of 14 cervical vertebrae, 7 thoracic vertebrae, 13 to 14 lumbar vertebrae fused with sacral vertebrae forming synsacrum and 7 coccygeal vertebrae. The hypapophyses of the 14th cervical vertebra and first two thoracic vertebrae were trifid in nature specific feature seen in Indian eagle owl. The vertebral column had characteristics features of hypapophyses, transverse process, pneumatic foramen and neural spine which enable the owl to adapt for head rotation and various task involving vertebrae.