Introduction
Human-induced rapid environmental change often alters nonhuman species’
reproductive, nutritional, and physiological behaviour (Cosmides and
Tooby 2000; Chartier et al. 2011; Sih et al. 2011). Both Asian
(Elephas maximus ) and African (Loxodonta africana )
elephants face land-use challenges more than other species due to their
substantial dietary requirement and extensive home range (Young et al.
2007; Kshettry et al. 2020; Roy et al. 2022). Known for their strategic
planning and cooperation, these social animals also become victims of
environmental modifications, and the resultant low fertility and high
calf mortality rates emerge as noted unforeseen consequences (Mar et al.
2012). Realizing the slow reproductive rate in elephants (Macdonald et
al. 2013), calf deaths directly influence their population dynamics.
While these sentient megaherbivores constantly adapt to land-use and
environmental change to increase survival rates, they demonstrate
various novel behaviours. Conversely, in order to survive many such
behaviour, of their affection for their offspring, comes to the
limelight when they frequently use the human domain than before. One
such behaviour is how they farewell their deceased calves and the herd
behaviour thereafter.
The manner in which nonhumans address the dying and the dead reflects
their cognition and emotional side (Hawley et al. 2016; Watson and
Matsuzawa 2018; Carter et al. 2020; Fernández-fueyo et al. 2021). Animal
behaviour and thanatology, therefore, remain a central part of
understanding the overall fitness of nonhuman species in a changing
landscape (Gill et al. 2020). Most animal species, unlike humans, pay
less interest to their dead conspecifics. Different species’ ’weak’
cognitive abilities and disease avoidance theories support this ’leaving
alone’ behaviour (Goldenberg & Wittemyer, 2019). However, cetaceans,
primates, and elephants show contrasting examples of strong behavioural
reactions to their deceased young ones. While most of such caring
behaviour between mother and the offspring among different species are
observed (Bercovitch, 2012), notably, the entire herd projects an
affectionate behaviour among elephants (Sikes 1971, McComb et al. 2006).
With up to 22 months of gestation, these K-strategist species invest a
lot of emotional energy in their young ones, even after their demise.
For instance, a behaviour where the elephant carcass parts were carried
across a distance, covering the carcass with vegetation (”weak” burial),
or observing the carcass over several hours has been covered in various
scholarships concerning African elephants (Douglas-Hamilton and
Douglas-Hamilton 1975; Goldenberg & Wittemyer, 2019). Apart from
elephants, burial behaviour has been observed in termites
(Reticulitermes fukienensis ) (Fernández-fueyo et al. 2021) but in
no other large mammals. Calf burials by elephants are among the
less-studied topics of thanatology, especially in Asia (Sharma et al.
2019), even though this practice is known to the conservation
gatekeepers. Elephants show a variety of behaviour ranging from
investigative, stationary, self-directed, social, and mourning behaviour
around their dead conspecific (Hawley et al. 2016; Goldenberg and
Wittemyer 2019; Watts 2019; Stephan et al. 2020).
Even though such sensory behaviours have been vastly studied, most of
these scholarships fail to report the exact cause of calf deaths and
weakly contribute to animal thanatology. The cause of death remains a
salient mediator to individual responsivity (Bercovitch 2020). We deem
it urgent as the herd’s behaviour (especially the mother) would vary in
deaths due to natural illness and accidents (injury and wounding).
Calves up to five years of age experience mortality risks due to various
factors such as maternal age, sex of the calf, inter-birth intervals,
and whether firstborn or later-born (Mar et al. 2012; Rutherford and
Murray 2020). Controlled studies have reported 43.3% of deaths due to
accidents among young calves (Mar et al. 2012), and therefore, the
resultant behaviour remains critical and dependent on the cause of
death.
From an evolutionary biology standpoint, natural illness and the
consequent death ultimately increase the fitness of the surviving
population (Fernández-fueyo et al. 2021). Thus, such an incident of calf
death wouldn’t escalate the conflict against humans. However, in case of
accidental deaths (attributed to humans), revenge behaviour has been
observed across many species, such as elephants (Chalcraft, 2015),
primates (Watts 2019), and more recently among orcas (Orcinus
orca ) (Anderson et al. 2016). Retaliation and revenge by elephants
escalate the human-elephant conflict (HEC) and pose a severe challenge
to wildlife managers and anthropologists. However, various
socio-ecological and political factors still determine the magnitude of
HEC, but such factors aren’t included in this article. This study rather
contributes to the ecological behaviour of elephants, both peri and
postmortem, while investigating into death cause through postmortem
reports of carcasses and attempting to bridge the two different elephant
species and draw commonalities and contrasts between the two as far as
thanatology is concerned.
While the elephants occupy only 5% of their historic home range
globally, India hosts more than sixty percent of the global Asian
elephant population despite being one of the most populated countries in
the world (Leimgruber et al. 2003; Sukumar 2006). As much as 78%
percent of their current habitat lies outside protected areas (PAs) in
heterogenous landscapes (Naha et al. 2020). With ever-increasing human
population alongside livestock heads and agricultural land on one hand
and conservation efforts to increase the large mammal population on the
other hand increases the human-nonhuman overlap (Sukumar 1989; Goswami
et al. 2015). The Asian elephant is listed as Endangered on the
International Union for Conservation of Nature (IUCN) Red List of
threatened species and is regarded as a sentient being for its
intelligence. Many novel behaviours come to the limelight when elephants
use non-forested areas more frequently. The study’s novelty lies in the
unique style of ceremonial burial of elephant calves inside tea gardens
(TGs) of north Bengal.
Along with a green cover and comparatively undisturbed passage for the
pachyderms, the tea gardens also provide ample stretch to trenches for
the burial of their deceased conspecifics. The trenches move out excess
water during the monsoon season to protect the tea bushes. However,
elephants reportedly use these depressions to bury their deceased
offspring. This study also presents the first photographic report of
dead calf burial by elephants in the tea gardens.
We aimed to (1) study the cause of death for the elephant calves, (2)
understand the rationale behind the unique carcass burial strategy, and
(3) observe the postmoretem behaviour among elephants near the burial
sites. We report the underlying reasons, from postmortem examination
reports for the calf deaths, anecdotal evidence of herd members during
peri and postmortem phases. This study contributes to the existing
literature on elephant behaviour and thanatology through a combination
of observation, analysis, and interpretation methods.