Female elephants thwart a male attempting to mate with a small female. Photo: Michael Nichols, Nat Geo Image Collection
Males of many species slow down in their pursuit of females as they age. Not so with elephants. Studies reveal that bull elephants increase the energy they put into reproduction as they get older.
In fact, elderly males invest much more effort in tracking down and mating with females than do younger male elephants, according to a new study.
The oldest bulls were the slowest walkers in the study when they were out of musth, but old-timers kicked it into high gear when musth began, and they walked faster than their younger competitors. These 50-somethings also patrolled territories 350 percent larger.
“They’re basically conserving all of their energy and then expending it when they go into musth,”
It seems that Musth males have a tremendous advantage over non-musth males as females find it so attractive that almost 80 percent of calves in the same population are sired by them, according to a 2007 study.
Male African savannah elephants continue to increase in body mass throughout their lives, which means that older male elephants often reach twice the size of both females and young males.
Iain Douglas-Hamilton, Founder of Save the Elephants and Senior Research Associate at the University of Oxford's Department of Zoology, said:
"Older bulls are not only larger and more energetic in mating than younger bulls but female elephants tend to prefer them, perhaps because their size demonstrates their survival skills over many years and seasons."
Even though males can begin mating around age 15, they don’t fall into a regular musth rhythm until they’re about 35. And by age 50, they’re rarin’ to go—an unusual timeline for most mammal species, whose reproduction tends to slow with age.
But even the biggest bulls need an extra boost.
“Musth males are like testosterone machines,”
says Lucy Taylor, a postdoctoral researcher at the University of Oxford who coauthored a new study on the phenomenon. They constantly drip strong-smelling urine, and specialised glands on their cheeks swell and ooze a thick liquid that contains pheromones.
“A male still needs to be able to see off his rivals, and musth gives that extra advantage to him when he’s competing for females,”
Key findings from the study include:
- Unlike other species, male African elephants increase the energy they put into reproduction as they get older
- Male elephants move faster and further in musth as they age.
- 50-year old males moved 50% faster and twice as far when in musth compared to those of 35 years old. Compared to 20-year olds, who have yet to come into full musth, the 50-year-olds move twice as fast and over three times as far.
- Simultaneously, the elephants move less when in non-musth as they get older.
- The change of behaviour as older elephants go into musth is so clear that it can be detected remotely just by using their movement patterns, rather than having to observe the elephants directly.
The male elephant behaviour study is published online in the Journal of Animal Ecology.
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