Percy J. Rendall, medical practitioner and naturalist, qualified as a licentiate of the Society of Apothecaries of London (LSA) in 1885. The next year he completed the Doctor of Medicine (MD) degree in Brussels and was admitted as a member of the Royal College of Surgeons (MRCS) of England. He must have stayed in west Africa for some time, for in 1892 he published "Notes on the ornithology of the Gambia", in The Ibis. Soon thereafter he came to the Cape Colony, where he requested an appointment as assistant medical officer at the Grahamstown asylum in 1893. As no appointment was made he moved to the South African Republic (Transvaal), where he was admitted to practice medicine that same year. No address for him is given in lists of medical practitioners, hence he may not have settled in any one place for long. However, in January 1894 he was in Barberton and during the next few years appears to have spent most of his time there.
In 1893 and 1894 Rendall presented insects or arachnids from the neighbourhood of Barberton to the South African Museum, Cape Town. Some of his collecting was probably done with W.L. Distant*, who visited the Transvaal from 1894 to 1898. The resulting specimens were described in 1898 by R.I. Pocock of the British Museum (Natural History) in a paper "On the Arachnida taken in the Transvaal and in Nyassaland by Mr W.L. Distant and Dr Percy Rendall", published in the Annals and Magazine of Natural History.
Rendall gave attention also to the mammals and birds of the Transvaal. His "Field-notes on the antelopes of the Transvaal" were published in the Proceedings of the Zoological Society of London (pp. 358-362) in 1895, and his "Notes on the ornithology of the Barberton district of the Transvaal" in The Ibis (pp. 165-176) in 1896. In 1899 he contributed (with F.V. Kirby*, R. Lydekker*, and F.C. Selous*) to Great and small game of Africa: an account of the distribution, habits, and natural history of the sporting mammals..., edited by H.A. Bryden*. However, by that time he was long gone from South Africa and had written "Natural history notes from the West Indies" (The Zoologist, 1897), and "Field-notes on the antelopes of Nyassaland" (Novitates Zoologica, 1898).