Histological Organisation of the Skin in the Asian Elephant
C. V. Rajani *
Department of Veterinary Anatomy, College of Veterinary and Animal Sciences, Pookode, Kerala Veterinary and Animal Sciences University (KVASU), Wayanad 673 576, Kerala, India.
K. P. Surjith
Department of Veterinary Anatomy, College of Veterinary and Animal Sciences, Pookode, Kerala Veterinary and Animal Sciences University (KVASU), Wayanad 673 576, Kerala, India.
H. S. Patki
Department of Veterinary Anatomy, College of Veterinary and Animal Sciences, Pookode, Kerala Veterinary and Animal Sciences University (KVASU), Wayanad 673 576, Kerala, India.
P. M. Deepa
Department of Veterinary Epidemiology and Preventive Medicine, College of Veterinary and Animal Sciences, Pookode, Kerala Veterinary and Animal Sciences University (KVASU), Wayanad 673 576, Kerala, India.
A. David
Animal Husbandry Department, Govt. of Kerala, India.
*Author to whom correspondence should be addressed.
Abstract
Elephants are the only extant members of Proboscidea, and their thick, wrinkled skin has important structural and functional relevance. This study examined the gross and microscopic organisation of the skin and hair of Asian elephants using post-mortem samples from one calf and three adult animals in Kerala. Skin samples from the lateral aspect of the head were processed for routine paraffin embedding, sectioned at 5-6 µm, and stained with haematoxylin and eosin and Gomori’s one-step trichrome. Whole mounts and negative casts of hair were used to examine medullary and cuticular patterns. Grossly, the skin was greyish-brown, markedly thick and wrinkled, with sparse, widely spaced hair; the calf was hairier than the adults. Histologically, the skin comprised a superficial, non-vascular epidermis and a thick, vascular dermis containing single primary hair follicles. The epidermis showed stratum basale, stratum spinosum, stratum granulosum and a thick stratum corneum, whereas stratum lucidum was absent. Papules, troughs and an undulating basal lamina were evident. Sweat glands, sebaceous glands and arrector pili muscles were not observed. Hair shafts had a narrow medulla, broad cortex and imbricate cuticular scales, with variation from proximal to distal regions. These observations describe normal integumentary and hair morphology in Asian elephants and provide a baseline for anatomical comparison, forensic identification and interpretation of pathological changes.
Keywords: Elephas maximus indicus, integument, epidermis, dermis, hair follicle, stratum corneum, thermoregulation, wildlife forensics