Evaluation of Demographics and Social Life Events of Asian (Elephas maximus) and African Elephants (Loxodonta africana) in North American Zoos

Abstract

This study quantified social life events hypothesized to affect the welfare of zoo African and Asian elephants, focusing on animals that were part of a large multi-disciplinary, multi-institutional elephant welfare study in North America. Age was calculated based on recorded birth dates and an age-based account of life event data for each elephant was compiled. These event histories included facility transfers, births and deaths of offspring, and births and deaths of non-offspring herd mates. Each event was evaluated as a total number of events per elephant, lifetime rate of event exposure, and age at first event exposure. These were then compared across three categories: species (African vs. Asian); sex (male vs. female); and origin (imported vs. captive-born). Mean age distributions differed (p<0.05) between the categories: African elephants were 6 years younger than Asian elephants, males were 12 years younger than females, and captive-born elephants were 20 years younger than imported elephants. Overall, the number of transfers ranged from 0 to 10, with a 33% higher age-adjusted transfer rate for imported African than imported Asian elephants, and 37% lower rate for imported females than males (p<0.05). Other differences (p<0.05) included a 96% higher rate of offspring births for captive-born females than those imported from range countries, a 159% higher rate of birthing event exposures for captive-born males than for their imported counterparts, and Asian elephant females being 4 years younger than African females when they produced their first calf. In summarizing demographic and social life events of elephants in North American zoos, we found both qualitative and quantitative differences in the early lives of imported versus captive-born elephants that could have long-term welfare implications.

Facilitating the social behaviour of bull elephants in zoos

“…A similar situation has been reported for Association of Zoos & Aquariums (AZA) accredited zoos in North America. In 2012, only 29 of 68 (43%) zoos with elephants housed a bull and only 11 of those 29 zoos had more than one bull, meaning only 16% of those bulls could interact with other bulls (Prado-Oviedo et al, 2016).…”

“…Adult bulls (those older than 25 years) have previously been considered solitary; therefore, zoos and logging camps have only given bulls access to the females for mating (Hartley, 2016). It is now being recognized that adult bulls are highly sociable, and that social interactions have important roles in physiological and behavioural functions, and influence social development in the herd (Veasey, 2006;Prado-Oviedo et al, 2016). Wood (2017) found that adult bulls spent 50Á3% (SD = 19Á9) of their free-choice time in a social situation under 30 m from another individual.…”

“…In AZA-accredited zoos the situation is even worse. In 2012, 93% (14 of 15 elephants) of African elephant bulls were under the age of 13 years of age and 63% (10 of 16 elephants) of Asian elephant bulls were under 20 years of age (Prado-Oviedo et al, 2016). For this reason alone, it is perhaps unsurprising that very few zoo elephants display full musth.…”

Environmental, social, management and health factors associated with within- and between-individual variability in fecal glucocorticoid metabolite concentrations in zoo-housed Asian and African elephants

“…Independent variables used for these analyses were chosen based on their significance in alreadypublished multi-variable models for other "gold standard" welfare indicators of the EWP (ovarian 140 cyclicity, stereotypy, body condition, foot and joint health, walking distance and recumbency, and serum cortisol). Full details regarding data collection and variable creation are provided in earlier publications [5][6][7][8][9][10][11][12][13][14][15][16]. Table 1 lists the welfare indicators and descriptions of the independent variables.…”

“…A recent 'Elephant Welfare Project (EWP)' took an epidemiological approach to investigating the 60 factors that impact zoo elephant welfare in North America [4]. That study, conducted by a multiinstitutional team of researchers and including 255 elephants at 68 Association of Zoos and Aquariums (AZA) accredited zoos, found that herd social structure, caretaker interactions, and enrichment, and feeding diversity correlated with a variety of welfare outcomes [5][6][7][8][9][10][11][12][13][14][15][16]. In particular, enrichment and social factors were important for reproductive activity and reducing stereotypic behaviors, diversity of Models exhibiting multi-collinearity, as defined by a variance inflation factor of greater than 10 and a 175 Condition Index of greater than 30, were not considered for further analysis.…”