The historical development of zoo elephant survivorship

Abstract

In the discussion about zoo elephant husbandry, the report of Clubb et al. (2008, Science 322: 1649) that zoo elephants had a "compromised survivorship" compared to certain non-zoo populations is a grave argument, and was possibly one of the triggers of a large variety of investigations into zoo elephant welfare, and changes in zoo elephant management. A side observation of that report was that whereas survivorship in African elephants (Loxodonta africana) improved since 1960, this was not the case in Asian elephants (Elephas maximus). We used historical data (based on the Species360 database) to revisit this aspect, including recent developments since 2008. Assessing the North American and European populations from 1910 until today, there were significant improvements of adult (≥10 years) survivorship in both species. For the period from 1960 until today, survivorship improvement was significant for African elephants and close to a significant improvement in Asian elephants; Asian elephants generally had a higher survivorship than Africans.Juvenile (<10 years) survivorship did not change significantly since 1960 and was higher in African elephants, most likely due to the effect of elephant herpes virus on Asian elephants. Current zoo elephant survivorship is higher than some, and lower than some other non-zoo populations. We discuss that in our view, the shape of the survivorship curve, and its change over time, are more relevant than comparisons with specific populations. Zoo elephant survivorship should be monitored continuously, and the expectation of a continuous trend towards improvement should be met.

Historical development of the survivorship of zoo rhinoceroses—A comparative historical analysis

“…The black and the white rhino thus join the list of species for which a historical improvement of husbandry success is detectable (Havercamp et al, 2019;Jaakkola & Willis, 2019;Jett & Ventre, 2015;Roller et al, 2021;Scherer et al, 2022;Wich et al, 2009). As stated previously, this development is to be expected and should not induce complacency (Scherer et al, 2022). Some limitations of the present study need to be mentioned.…”

“…The results demonstrate an improvement in survivorship over time, particularly in animals ≥1 year of age, suggesting a certain degree of improvement of husbandry success. The black and the white rhino thus join the list of species for which a historical improvement of husbandry success is detectable (Havercamp et al, 2019; Jaakkola & Willis, 2019; Jett & Ventre, 2015; Roller et al, 2021; Scherer et al, 2022; Wich et al, 2009). As stated previously, this development is to be expected and should not induce complacency (Scherer et al, 2022).…”

“…Our evaluation followed the principles outlined by Roller et al, (2021) and Scherer et al, (2022). We obtained global records for three zoo-kept rhino species from Species360 (ZIMS for Husbandry), an online database platform in current use by more than 1200 zoos worldwide (and also including historic data from a further 600 zoos) to manage their animal data, with known dates of birth and death, from which the subsequent data were calculated (Species360 Research Data Agreement # 2019-Q3-RR3).…”

What is the role of the studbook in zoo and aquarium research?

“…In elephants, for example, initial research on demographics and longevity (Clubb et al, 2008) highlighted points that sparked a much wider range of studies on reproduction (Clubb et al, 2008; Freeman et al, 2009) and health (Lewis et al, 2009; Wendler et al, 2020). This sustained research focus has resulted in measurable improvements in survivorship (Scherer et al, 2022).…”

Losing the forest for the tree? On the wisdom of subpopulation management

“…The zoo and aquarium environment has changed over the decades and is likely to continue to do so. Husbandry practices, exhibition techniques, and veterinary care have and will evolve, resulting in changes in animal life history (e.g., Scherer et al, 2022; Tidière et al, 2016), likely through a relaxation of some kinds of selection. For animals that live outdoors, it is likely that their abiotic environment has and will continue to change due to climate change.…”