Header

UZH-Logo

Maintenance Infos

Elephant body mass cyclicity suggests effect of molar progression on chewing efficiency


Schiffmann, Christian; Hatt, Jean-Michel; Hoby, Stefan; Codron, Daryl; Clauss, Marcus (2019). Elephant body mass cyclicity suggests effect of molar progression on chewing efficiency. Mammalian Biology - Zeitschrift für Säugetierkunde, 96:81-86.

Abstract

Elephants do not replace deciduous teeth once with permanent teeth as most mammals, but replace a single cheek tooth per jaw-side five times in their lives in a process called molar progression. While this gradual process has been well-documented for the purpose of age determination, a less-considered possible side effect of this progression is that functional chewing surface fluctuates, being larger when two cheek teeth are both partially in use and smaller when only one cheek tooth is used fully. We found that body mass of both breeding and non-breeding female zoo elephants (Elephas maximus, Loxodonta africana) shows a cyclic undulation with peaks separated by many years, which is therefore unrelated to reproduction or annual seasonality. We propose variation in functional chewing surface, resulting chewing efficiency, and resulting increased food intake and/or digestive efficiency as the underlying cause. As elephants reproduce all year-round and thus are not synchronized in their molar progression pattern, climate-related fluctuations in resource availability are likely to mask this pattern in free-ranging animals. In contrast, it emerges under the comparatively constant zoo conditions, and illustrates the relevance of the dental apparatus for herbivorous mammals. The combination of variable chewing efficiency and resource availability in free-ranging elephants may render these species particularly prone to reported inter-individual fitness differences.

Abstract

Elephants do not replace deciduous teeth once with permanent teeth as most mammals, but replace a single cheek tooth per jaw-side five times in their lives in a process called molar progression. While this gradual process has been well-documented for the purpose of age determination, a less-considered possible side effect of this progression is that functional chewing surface fluctuates, being larger when two cheek teeth are both partially in use and smaller when only one cheek tooth is used fully. We found that body mass of both breeding and non-breeding female zoo elephants (Elephas maximus, Loxodonta africana) shows a cyclic undulation with peaks separated by many years, which is therefore unrelated to reproduction or annual seasonality. We propose variation in functional chewing surface, resulting chewing efficiency, and resulting increased food intake and/or digestive efficiency as the underlying cause. As elephants reproduce all year-round and thus are not synchronized in their molar progression pattern, climate-related fluctuations in resource availability are likely to mask this pattern in free-ranging animals. In contrast, it emerges under the comparatively constant zoo conditions, and illustrates the relevance of the dental apparatus for herbivorous mammals. The combination of variable chewing efficiency and resource availability in free-ranging elephants may render these species particularly prone to reported inter-individual fitness differences.

Statistics

Citations

Dimensions.ai Metrics
2 citations in Web of Science®
2 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

0 downloads since deposited on 05 Jun 2019
0 downloads since 12 months

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:05 Vetsuisse Faculty > Veterinary Clinic > Department of Small Animals
Dewey Decimal Classification:570 Life sciences; biology
630 Agriculture
Scopus Subject Areas:Life Sciences > Ecology, Evolution, Behavior and Systematics
Life Sciences > Animal Science and Zoology
Uncontrolled Keywords:Animal Science and Zoology, Ecology, Evolution, Behavior and Systematics
Language:English
Date:1 May 2019
Deposited On:05 Jun 2019 15:07
Last Modified:29 Jul 2020 10:45
Publisher:Elsevier
ISSN:1616-5047
OA Status:Closed
Publisher DOI:https://doi.org/10.1016/j.mambio.2018.12.004

Download

Closed Access: Download allowed only for UZH members