Mate guarding by a male
New Delhi, April 22: Wildlife biologists have spotted elements of deception and rejection, persistent pursuits as well as sneaky behaviour in the first rigorous study of courtship among Asian elephants conducted in Assam's Kaziranga National Park.
The three-year long study by researchers at the Indian Institute of Science, Bangalore, has also suggested that female elephants are able to reject males they do not fancy, although the choice available to them is at times limited by competition among males.
Their findings, just published in the international research journal Behaviour, also indicate that female elephants don't necessarily look out for tusks, but prefer large males in a physiological state called musth, a temporary sexually-heightened state in which testosterone levels spike to 50 times the normal values.
"Some observations were surprising," said Karpagam Chelliah, a post-doctoral fellow at the IISc Centre for Ecological Sciences. "Some female elephants not only solicited dominant males as expected, but also sneaked away to solicit sub-dominant males," she told The Telegraph.
Under standard evolutionary theory, females across the animal kingdom would be expected to choose dominant males with biological traits - such as superior health - that can increase the chance of good offspring, a key evolutionary driver in reproductive choice.
While many of the female elephants in Kaziranga were guarded by dominant males, the scientists observed that elephants at times resorted to sneaky mating strategies, slinking away when the male's guard had slackened or when the dominant male was involved in combat with a rival male.
The scientists say there is a biological explanation for this behaviour. "It is possible the females are trying to maximise the chances of fertilisation," Chelliah said. The IISc researchers observed that in their study, nearly half of all mating attempts and a considerable number of those even by males in musth were unsuccessful.
The researchers, who at times positioned themselves on watchtowers to look out for elephants in the tall grasses of Kaziranga, also spotted male competition, males guarding female elephants from rival males, and females unwilling to cooperate with males, leading to unsuccessful mating. The females were able to dislodge mounted males from their backs, irrespective of the size of the male.
Forest department records suggest that Kaziranga, a riverine habitat with tall grasses, had about 150 adult males and 370 adult females during 2011.
Courtship behaviour among African elephants had been studied in Kenya in the early-1980s. But male Asian elephants are smaller than male African elephants and display some differences - many male Asian elephants, for instance, do not have tusks which are always found on African male elephants.
Across the animal and bird kingdom, biologists have long observed females choose males relying on flamboyant displays of certain features - peacocks display long coloured tail feathers, while certain deer have strikingly long and branched antlers.
Charles Darwin had in 1871 proposed that male traits such as antlers may serve as a weapon in male-to-male combat and ensure superiority of one male over others, while other such as colourful feathers may serve as ornaments to attract females.
"Our observations suggest that tusks are less important than body size and testosterone spikes that occur when bull elephants come into musth," said Raman Sukumar, professor of ecological sciences at the IISc, who guided the study.
Scientists believe tusks evolved in the ancestors of elephants tens of millions of years ago when they were important - perhaps to obtain food or as a weapon against predators. But this may have changed over geological timescales as the Earth passed through ice age phases and vegetation periodically became sparse, said Sukumar, who has studied elephants across the country for over 30 years.