In terms of age and gender, we found that adults were killed more often than
other age groups, but this was roughly proportional to their representation in the
population. What is striking, however, is that the proportion of adult males killed
was nearly three times higher than that expected from their representation in the
population. The reasons for this are uncertain, but it is possible that adult males
range over larger areas, raid crops in villages more frequently, and thus cross
railways more often than females do (Sukumar 1989; Sukumar et al. 2003; Roy
2010; Williams et al. 2001). It is also noteworthy that juveniles were killed to a
lesser extent than expected, implying that they are alert and protected within a
family group, whereas calves were killed more often than expected from their
percentage of the population, probably because of their inability to respond quickly
to dangerous situations.
The concentration of accidents at night was probably a consequence of elephant
movement patterns, rather than resulting from variation in the number of circulating
trains. In fact, about 80% of accidents occurred between 18:00 and 6:00, although
only 35% of trains operate at this time; this is probably because in daytime, elephants tend to rest in more dense forests, moving towards cultivated fields at night
(Sukumar 2003) and eventually crossing railway lines. Other studies have reported
similar patterns, showing a matching between animal daily activity patterns and
collisions with trains. For instance, Ando (2003) found that 69% of the collisions of
Sika deer Cervus nippon with trains in the eastern Hokkaido line, Japan, were
recorded in the evening, which is the period when animals move between resting
and feeding sites.
The seasonal distribution of collisions may also be a consequence, at least partly,
of elephant movements from forests to agricultural areas, where they forage for
crops. This is supported by the close matching between accident peaks and the
harvest seasons of maize and paddy rice, as well as the observed spatial and
temporal patterns of elephant raiding of crops in the region. Similar patterns have
been observed elsewhere in India, with Singh et al. (2001) reporting that 78% of
collisions with trains in the Rajaji National Park occurred in January–June and
peaked in May, which matches the wheat and sugar cane cultivation/harvest season.
Likewise, Sarma et al. (2006) in Assam found one peak in June–July during the
active monsoon period, when elephants move away from floodplains to higher
ground through which railway tracks run, and another in November that coincides
with the paddy crop harvesting season. Studies on other herbivores, such as Sika
deer (Ando 2003), moose (Alces alces, Andersen et al. 1991), and roe deer
(Capreolus capreolus, Kusta et al. 2014), also suggested that collisions with trains
peaked during the seasons when animals moved widely in search of food.
The spatial distribution of train–elephant collisions was uneven, with the occurrence of a few well-defined hotspots. Reasons for this are uncertain, but it may be the
result of a number of factors, such as a variation in animal abundance, activity, and
behaviour, habitat distribution, landscape topography, and rail design, as described
for other species elsewhere (Gundersen and Andreassen 1998; Inbar and Mayer 1999;
Haikonen and Summala 2001; Joyce and Mahoney 2001; Mysterud 2004; Roy 2010).
In our case, accidents seemed concentrated in areas where the railway track crossed
10 Railways and Wildlife: A Case Study …
169
other age groups, but this was roughly proportional to their representation in the
population. What is striking, however, is that the proportion of adult males killed
was nearly three times higher than that expected from their representation in the
population. The reasons for this are uncertain, but it is possible that adult males
range over larger areas, raid crops in villages more frequently, and thus cross
railways more often than females do (Sukumar 1989; Sukumar et al. 2003; Roy
2010; Williams et al. 2001). It is also noteworthy that juveniles were killed to a
lesser extent than expected, implying that they are alert and protected within a
family group, whereas calves were killed more often than expected from their
percentage of the population, probably because of their inability to respond quickly
to dangerous situations.
The concentration of accidents at night was probably a consequence of elephant
movement patterns, rather than resulting from variation in the number of circulating
trains. In fact, about 80% of accidents occurred between 18:00 and 6:00, although
only 35% of trains operate at this time; this is probably because in daytime, elephants tend to rest in more dense forests, moving towards cultivated fields at night
(Sukumar 2003) and eventually crossing railway lines. Other studies have reported
similar patterns, showing a matching between animal daily activity patterns and
collisions with trains. For instance, Ando (2003) found that 69% of the collisions of
Sika deer Cervus nippon with trains in the eastern Hokkaido line, Japan, were
recorded in the evening, which is the period when animals move between resting
and feeding sites.
The seasonal distribution of collisions may also be a consequence, at least partly,
of elephant movements from forests to agricultural areas, where they forage for
crops. This is supported by the close matching between accident peaks and the
harvest seasons of maize and paddy rice, as well as the observed spatial and
temporal patterns of elephant raiding of crops in the region. Similar patterns have
been observed elsewhere in India, with Singh et al. (2001) reporting that 78% of
collisions with trains in the Rajaji National Park occurred in January–June and
peaked in May, which matches the wheat and sugar cane cultivation/harvest season.
Likewise, Sarma et al. (2006) in Assam found one peak in June–July during the
active monsoon period, when elephants move away from floodplains to higher
ground through which railway tracks run, and another in November that coincides
with the paddy crop harvesting season. Studies on other herbivores, such as Sika
deer (Ando 2003), moose (Alces alces, Andersen et al. 1991), and roe deer
(Capreolus capreolus, Kusta et al. 2014), also suggested that collisions with trains
peaked during the seasons when animals moved widely in search of food.
The spatial distribution of train–elephant collisions was uneven, with the occurrence of a few well-defined hotspots. Reasons for this are uncertain, but it may be the
result of a number of factors, such as a variation in animal abundance, activity, and
behaviour, habitat distribution, landscape topography, and rail design, as described
for other species elsewhere (Gundersen and Andreassen 1998; Inbar and Mayer 1999;
Haikonen and Summala 2001; Joyce and Mahoney 2001; Mysterud 2004; Roy 2010).
In our case, accidents seemed concentrated in areas where the railway track crossed
10 Railways and Wildlife: A Case Study …
169