Tooth wear in captive rhinoceroses (Diceros, Rhinoceros, Ceratotherium: Perissodactyla) differs from that of free-ranging conspecifics

Tooth wear can affect body condition, reproductive success and life expectancy. Poor dental health is frequently reported in the zoo literature, and abrasion-dominated tooth wear, which is typical for grazers, has been reported in captive browsing ruminants. The aim of this study was to test if a similar effect is evident in captive rhinoceros species. Dental casts of maxillary cheek teeth of museum specimens of captive black (Diceros bicornis; browser), greater one-horned (Rhinoceros unicornis; intermediate feeder) and white rhinoceroses (Ceratotherium simum; grazer) were analysed using the recently developed extended mesowear method for rhinoceroses. Captive D. bicornis exhibited significantly more abrasiondominated tooth wear than their free-ranging conspecifics (p<0.001), whereas captive C. simum exhibited significantly less abrasion-dominated tooth wear, particularly in the posterior cusp of the second molar (p=0.005). In R. unicornis, fewer differences were exhibited between free-ranging and captive animals, but tooth wear was highly variable in this species. In both free-ranging and captive D. bicornis, anterior cusps were significantly more abrasion-dominated than posterior cusps (p<0.05), which indicates morphological differences between cusps that may represent functional adaptations. By contrast, tooth wear gradients between free-ranging and captive animals differed, which indicates ingesta-specific influences responsible for inter-tooth wear differences. Captive D. bicornis exhibited more homogenous tooth wear than their free-ranging conspecifics, which may be caused by an increase in the absolute dietary abrasiveness and a decrease in relative environmental abrasiveness compared to their free-ranging conspecifics. The opposite occurred in C. simum. The results of this study suggest that diets fed to captive browsers are too abrasive, which could result in the premature loss of tooth functionality, leading to reduced food acquisition and processing ability and, consequently, malnourishment. Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-94211 Supplemental Material Originally published at: Taylor, L A; Müller, D W H; Schwitzer, C; Kaiser, T; Codron, D; Schulz, E; Clauss, Marcus (2014). Tooth wear in captive rhinoceroses (Diceros, Rhinoceros, Ceratotherium: Perissodactyla) differs from that of free-ranging conspecifics. Contributions to Zoology, 83:107-117. S1. Museum and specimen information. Museum Abbreviation Museum Name Specimen identification Free-ranging Captive AMNH American Museum of Natural History New York 54454, 54455, 51854, 146718 IZW Institute for Zoo and Wildlife Research Berlin 371/2003, 0175, 538, 2001, 835/93 MHN Museum National d’Histoire Naturelle Paris A2277 1944-278, 1961-195, 1974124, 1960-59, 1967-101, 2005-297 NHB Naturhistorisches Museum Bern 1021034 10594, n.N.082 NHM Natural History Museum London 1874.11.2.2, 1876.2.15.5, 19.7.15.511, 1907.2.26.1, 1948.1.28.6, 1962.7.6.1, 1962.7.6.5, 1962.7.6.6, 1967.7.6.4, 1976.9.26.6, 2.11.18.7, 1951.11.30.2, 72.12.30.1, 72.739, 84.1.22.1+2, 1967.8.31.4, 25.5.23.1, 52.12.9.1, 75.2384 1961.5.10.1 NHS Staatliches Museum für Naturkunde Stuttgart 32018, 7564, 1218 NMAB Naturmuseum Augsburg 01, 02 NMB Naturhistorisches Museum Basel 7351, C.1798 n.N.007 NMP National Museum Prague 165, 2007, 25963, 25964, 47655, 48347, 489, 1/188, 2006, 47145 NMS National Museums Scotland Edinburgh 200.369, 2008 unreg, 2003.5, 2008.124, 2000.33, 2004.75, 2005.129.2, 2008.127, 2009.10 NMW Naturhistorisches Museum Wien 4279, 4291 55210 NRM Naturhistoriska Riksmuseet Stockholm A591324, A591596 OUM Oxford University Museum of Natural History 7118, 3827 PMJ Phyletisches Museum Jena 651 SMF Forschungsinstitut und Naturmuseum Senckenberg Frankfurt am Main 22660, 699, 664 15934, 40543 Zoo Basel Zoo Basel Zoo Basel ZFMK Zoologisches Forschungsmuseum Alexander Koenig Bonn 88.16 ZMB Museum für Naturkunde Berlin 35744, 40053, 41480, 46166, 83230, 83232 ZMH Zoologisches Museum Hamburg 35744, 40053, 41480, 46166, 83230, 83232, 2551, 2552 8405, 9328, 8385, 10060 ZMZ Zoologisches Museum Zürich 83226, 10806, 10927 18129, 19660, 20165, 20273 ZSSM Zoologische Staatssammlung München 1963/160, AM416, 1912/4199, 1912/4202 2001/33