Locomotor adaptations and proportions of the Pelvic limb in Galliform birds

Abstract

Galliform birds have a rather generalized hind limb skeleton without extreme modification or reductions in their long bones in spite of exhibiting various types of adaptations for locomotion. The aim of the present study is to test the relationship between the adaptations and the morphology of the proximal and middle segment bones of the pelvic limb in Galliform birds turkey, guinea fowl, chicken and quail. The eight femur and tibia each from adult males of each species were collected. The diameters and functional lengths of the bones were measured and three functional indices were built viz., Gluteal index (GI), Femur robust index (FRI) and tibia robust index (TRI) were analyzed for the relationship between adaptation and morphology. All the indices were high in turkey, followed by guinea fowl and chicken and the quail showed the least value. The increased GI from turkey is related to accommodate the well-developed gluteus medius muscle which increases mechanical efficiency for speed. The FRI were robust in turkey and guinea fowl than chicken and quail which indicated that more area was provided for well–developed muscle on hip and thigh in turkey and guinea fowl which help in the great mean moments and high speed locomotion. The increased TRI in turkey and guinea fowl is related to strong support and propulsion of the body mass during locomotion. It is concluded that the turkey and guinea fowl have better adapted for the speed locomotion than chicken and quail.