Birth statistics for African (Loxodonta africana) and Asian (Elephas maximus) elephants in human care: history and implications for elephant welfare

An adolescent female African elephant (Loxodonta africana) gave birth to an abnormal calf

Maternal nutrition and the uterine environment can influence placental development in mammals, leading to the birth of abnormal infants who often experience difficulties in independent standing. This article documents an adolescent female African elephant (Loxodonta africana) giving birth to an African elephant calf with a shoulder height below the mean, and its inability to stand for the first 10 h after birth, a time span that significantly exceeds the average duration for independent standing. Through the implementation of assisted feeding and assisted standing measures, the calf eventually achieved independent standing and nursing from its mother after 27 h and subsequent catch-up growth at 5 months of age. This study presents the first case report on the growth parameters during pregnancy of an adolescent African elephant, the birth and care (feeding, assisted standing) of a small African elephant calf with the inability to stand alone and nurse independently for several hours, highlighting pregnancy may influence the growth of cows during their ongoing growth and development phase, the calf's survival and subsequent catch-up growth at 5 months of age. These findings offer valuable insights into the care of abnormal African elephant calves.

Administration of Altrenogest to Maintain Pregnancy in Asian Elephants (Elephas maximus)

Simple Summary

The Asian Elephant (Elephas maximus) is an IUCN (International Union of the Conservation of Nature) Endangered species that has interacted with humans for centuries. Despite advances in captive elephant breeding knowledge, worldwide populations continue to decline. Progesterone is a key reproductive hormone for the maintenance of pregnancy in mammalian species. The monitoring of serum progesterone levels has become a key method of management for captive breeding of elephants. The synthetic progesterone, altrenogest, has been administered to multiple species of mammals both for management of estrus and maintenance of pregnancy. This paper details three Asian elephant pregnancies maintained by the administration of altrenogest after endogenous progesterone levels decreased below the point needed to maintain pregnancy. Pharmacokinetic parameters of altrenogest administered orally as a single dose to nonpregnant pilot study elephants are presented as preliminary data on the administration of this drug to Asian elephants as a pharmacological means of maintaining pregnancy to term.

Abstract

Progesterone and progesterone derivatives are key hormones in pregnancy maintenance in mammalian species. Cessation of pregnancy, including birth or miscarriage, is certain if levels of these hormones drop below a given species-specific requirement necessary to maintain pregnancy. The synthetic progestin, altrenogest, is FDA-approved in the United States for suppression of estrus or synchronization and is administered extra-label to multiple species to maintain pregnancies in cases of luteal deficiency or otherwise abnormally low progesterone levels. Three pregnant Asian elephants received altrenogest from 41 to 131 days during the final trimester of pregnancy, with parturition occurring from 15 to 31 days after altrenogest administration stopped. A single dose of 0.2 mg/kg altrenogest administered to two nonpregnant Asian elephants provided pilot pharmacokinetic data. Serum samples from two of the three clinical cases and the two pilot study elephants were analyzed using Ultra Performance Liquid chromatography coupled to a triple quadruple mass spectrometer (UPLC-MS). Small sample numbers limited analysis; however, the following were determined: AUC∞ of 635.4 ± 73.8 ng*h/mL, Cmax of 30.2 ± 14.4 ng/mL at a Tmax of 4 ± 2.8 h, terminal T1/2 of 47.5 ± 3.0 h, MRT of 36.0 + 3.4 h and Vd/F of 1243.8 + 275.0 L/kg. These data and the three described cases serve as an indication that altrenogest can be administered to Asian elephants as an exogenous progestin to support pregnancy in elephant pregnancies with low endogenous progestin levels.

Age-based variation in calf independence, social behavior and play in a captive population of African elephant calves

African elephant calves are highly social and their behavioral development depends heavily on interactions with other elephants. Evaluating early social behaviors offers important information that can inform management decisions and maximize individual- and population-level welfare. We use data collected from the population of elephants at the San Diego Zoo Safari Park in Escondido, CA to evaluate developmental trajectories of spatial independence and social behavior in nine elephant calves across a range of ages. As calves aged, the probability of being further from mothers also increased. Tactile interactions were common among calves, with all individuals either initiating or receiving physical touches from other elephants in a large proportion of focal scans. While the probability of initiating tactile interactions tended to decline with increases in calf age, the probability of receiving tactile interactions from other elephants remained invariant with regard to this variable. The social play was also common, occurring in a fifth of all focal scans. While there was evidence that social play tended to decline with increases in calf age, results suggest additional factors may be useful in characterizing patterns in play behavior at the individual level. Calves most frequently engaged in play with individuals of similar age but showed substantial variation in play partner choice. Results of this study suggest that maintaining groups of elephants in captivity with diverse age structure positively contribute to their healthy social development.

Insights into Activity of Zoo Housed Asian Elephants (Elephas maximus) during Periods of Limited Staff and Visitor Presence, a Focus on Resting Behaviour

Historically, behaviour of zoo housed species during hours of limited staff and visitor presence has been poorly studied, largely due to the lack of appropriate technology. Advances in digital monitoring equipment and facility design by European elephant holders has given researchers scope to accurately evaluate behaviour for this species over 24 hrs. Various behavioural indicators of welfare have now been identified for zoo housed elephants; however the relationship between resting behaviour and welfare experience has been an area highlighted to require additional research. Lying rest is a potential positive welfare indicator for this species, with studies suggesting that engagement in lying rest can be used to monitor both psychological and physiological wellbeing. Throughout this work we aim to give insights into the behaviour of individual Asian elephants at ZSL Whipsnade Zoo, specifically between the hours of 16:00 and 10:00. In addition to presenting the activity budgets of our study individuals during these times, we explore individual engagement in resting behaviour. Furthermore, we evaluate the social associations of our study group during rest. We provide evidence that unrelated individuals can form strong associations with conspecifics when resting and show that life history is a factor to consider when evaluating social compatibility between group members. Finally, we demonstrate the positive role that calves and juvenile individuals can play in facilitating meaningful associations between group members during rest. Our study highlights the importance of evaluating behaviour during understudied time periods in order to obtain a holistic view of individual welfare, further emphasising the importance of adopting an evidence-based approach to management for this species in zoos.

Causes and correlates of calf mortality in captive Asian elephants (Elephas maximus)

Juvenile mortality is a key factor influencing population growth rate in density-independent, predation-free, well-managed captive populations. Currently at least a quarter of all Asian elephants live in captivity, but both the wild and captive populations are unsustainable with the present fertility and calf mortality rates. Despite the need for detailed data on calf mortality to manage effectively populations and to minimize the need for capture from the wild, very little is known of the causes and correlates of calf mortality in Asian elephants. Here we use the world's largest multigenerational demographic dataset on a semi-captive population of Asian elephants compiled from timber camps in Myanmar to investigate the survival of calves (n = 1020) to age five born to captive-born mothers (n = 391) between 1960 and 1999. Mortality risk varied significantly across different ages and was higher for males at any age. Maternal reproductive history was associated with large differences in both stillbirth and liveborn mortality risk: first-time mothers had a higher risk of calf loss as did mothers producing another calf soon (<3.7 years) after a previous birth, and when giving birth at older age. Stillbirth (4%) and pre-weaning mortality (25.6%) were considerably lower than those reported for zoo elephants and used in published population viability analyses. A large proportion of deaths were caused by accidents and lack of maternal milk/calf weakness which both might be partly preventable by supplementary feeding of mothers and calves and work reduction of high-risk mothers. Our results on Myanmar timber elephants with an extensive keeping system provide an important comparison to compromised survivorship reported in zoo elephants. They have implications for improving captive working elephant management systems in range countries and for refining population viability analyses with realistic parameter values in order to predict future population size of the Asian elephant.

Fecundity and population viability in female zoo elephants: problems and possible solutions

We previously reported that African (Loxodonta africana) and Asian (Elephas maximus) female elephants in European zoos have shorter adult lifespans than protected conspecifics in range countries. This effect was the cause of greatest concern in Asian elephants, and risk factors within this species included being zoo-born, transferred between zoos, and possibly removed early from the mother. Here, we investigate these risk factors further; assess fecundity and sustainability in European zoos; and propose testable hypotheses as to the causes of these animals’ problems. Although imported wild-born Asian elephants live longer than zoo-born conspecifics, being imported when juvenile or adult appears no more protective than being imported in infancy, suggesting that the benefits of being wild- rather than zoo-born are conferred early in life. Zoo-born Asian neonates are significantly heavier than those born to working animals in range countries, with a possible tendency to be fatter. In zoos, African elephants have tended to be removed from their mothers at older ages than young Asians, and were also transferred between zoos significantly less often: factors that could possibly underlie this species’ lower calf losses and improving adult survivorship in Europe. Both species have low fecundity in European zoos compared to in situ populations, and are not self-sustaining, declining at approximately 10% per annum if reliant on captive-bred females under historically prevailing conditions. Data from other species suggest that stress and/or obesity are parsimonious explanations for the suite of problems seen. We recommend specific screens for testing these hypotheses, and for potentially identifying vulnerable individuals within the extant zoo populations.