In 1834 a male Indian Rhinoceros, Rhinoceros unicornis, was purchased by the London Zoological Society at the request of the anatomist, Richard Owen. When this rhinoceros died fifteen years later, the dissection performed by Owen led to the first discovery of the pedal or parathyroid glands on which much endocrinal research is based.
https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2818.1966.tb00576.x
“In his detailed description of the anatomy, Owen refers to ‘a small compact yellow glandular body attached to the thyroid at the point where the vein emerged’—a structure we now know as the parathyroid gland. The original preparation in which Owen made the observation is still to be seen in the Hunterian Museum at the College. It measures 30×14×8 cm and consists of part of the larynx and trachea of the rhinoceros, showing the lateral lobe of the thyroid with a parathyroid attached to its upper extremity and partly embedded in its substance” B Modarai, A Sawyer, and H Ellis, The glands of Owen. J R Soc Med. 2004 Oct; 97(10): 494–495.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1079622/
Anatomical drawings from a dissection of an Indian rhinoceros that died in London Zoo in 1849. From Richard Owen, 1852. On the anatomy of the Indian rhinoceros (Rh unicornis, L.). Transactions of the Zoological Society of London 4 (2): 31-58
https://www.biodiversitylibrary.org/item/91267#page/547/mode/1up
