It’s been months since I was in the ‘hot-box’. The unseasonal rain that scattered Tsavo’s elephants has passed and we have seen the return of the dry season winds. In the past few weeks, they’ve wicked the moisture from the surface of the soil and the grasses have brown-withered. The days of plenty are over. Elephants can no longer rely on the seasonal waterholes and wallows, and are returning to permanent water.
In my absence, the steel filming hide we call the ‘hot-box’ had become a ‘wet-box’ – it had been submerged for months. We spent the first hour of the day bucketing out a ton of anaerobic sludge. I spent the hours afterwards, evicting toads and giant centipedes that had sought refuge in the gloomy, fetid interior.
Last year, I spent several weeks confined underground in it. In all that time, I never saw as many elephants as I did recently – more than 400 drifted in to drink. There was only a handful of big bulls though, and not one of them a ‘tusker’.
The last time I spent time in the ‘hot box’, Satao was alive, and came to drink with his four ‘askaris’.
Much of the press about the death of Satao, has mentioned how important the last remaining big tuskers are to the gene ‘pool’. The implication being that they are the last repository of ‘big tusk’ genes, and are responsible for passing them on. If we lose them, then we won’t see big tuskers in the future. Back underground again, and waiting for the ‘magic hour’ light, I wondered if that was right.
For the remaining tuskers to be passing on their ‘big tusk’ legacy, tusk size needs to be inherited, and the big tuskers sexually active.
I don’t know of any studies on the inheritability of tusk size, but what we’ve seen suggests that tusk ‘character’ runs in families. Closely related elephants often have similar tusks eg. crossed tusks, or narrow ‘tooth picks’. Occasionally they are tusk-less. Researchers in Amboseli ( the Amboseli Elephant Project is the longest-running ‘vertical’ study of African elephants ) can sometimes place an elephant in the right family using physical traits alone – tusk ‘character’ amongst them.
If tusk size is inherited, is it passed on by males? It probably is, but in almost every animal, some genes are sex-linked. In humans, haemophilia and red-green colour blindness are sex-linked traits – carried by females, but expressed in males.
It would be ironic if we protected bulls to save the gene pool, only to find that the future of ‘big tusk’ genes lay with the cows.
Are the big tuskers passing on their genes?
Elephants grow throughout life – and so do their tusks. Bulls with the largest tusks are often the oldest. Tusks indicate age, not virility. Bulls can live to be 70, but their reproductive prime is likely to be closer to 40-45. This is when they come into musth for longer, and when they mate most.
Satao was about 50 when he died, but over the year and a half we filmed him, we never saw him mate – nor did we ever see him in musth. By that age, as a dominant bull, he had probably sired a disproportionate number of offspring. By the time he became a true tusker, he is likely to have passed on his genes many times over. Those genes are out there in the population, in his progeny – they will only ‘show’ when the cows and bulls he sired, grow older.
In the big tusk gene ‘pool’ it is possible that the very biggest tuskers are a quiet ‘back-water’ – their genes already passed on, their ability to reproduce slowly waning. They are the ‘elder statesmen’ of elephant society.
Perhaps more important to the survival of ‘big tusk’ genes are the bulls and cows that carry disproportionately large tusks, yet are still in their reproductive prime.
If they live long enough, their tusks will grow and they’ll earn the accolade ‘big tusker’ (for a bull this reflects tusks over 45kg). For now, they are doing the essential work of passing on the ‘big tusk’ genes.
In the long term, I suspect that the survival of ‘big tusk’ genes depends more on what is happening at the population level, rather than at the individual – and there, the outlook is less encouraging.
Tsavo’s elephants have been slaughtered for their tusks for hundreds of years. Swahili merchants, Arab traders, colonial hunters, now poachers – the onslaught has ramped up in the last few years. They have all targeted elephants with the largest tusks – it’s a strong selection pressure, and the result is the evolution of elephants with smaller tusks. Today, Africa’s elephants have tusks half the size of their forebears.
The same pressure is probably driving up the proportion of tusk-less elephants.
Tusks are not essential, but there is no doubt they make life easier. I once saw Satao asleep, leaning slightly forward, his huge tusks propping up his head. Besides being used as a headrest, we’ve seen them used as weapons, or for digging up tubers, prising bark from trees, or excavating for minerals and water. Bulls don’t need tusks to mate, or for cows to find them attractive – sheer physical size is more important. A huge, tusk-less Tsavo bull named ‘Thunder’ is testament to that. Like a small percentage of the population, he is genetically tusk-less.
In China and Uganda, poaching has caused a gene responsible for tusk-lessness to spread. I think it is very likely that the same is happening in Tsavo and that the proportion of tusk-less elephants is increasing.
If poaching continues, it seems inevitable that we will continue to see a gradual decline in tusk size, and fewer elephants with tusks.
So what of Satao’s fellow big tuskers – the surviving incumbents…?
I think they are very important. We should be cautious of assuming, however, that their protection is all that is needed to ensure the survival of ‘big tusk’ genes.
As a group, they are the finest bulls left in Africa – the last of an unbroken line of magnificent ‘big tuskers’, that has trodden Tsavo’s red soil for thousands of years.
They are the current poster boys for their species, and a visible rallying point. The international outcry that followed the death of Satao, is testament to this.
Their potential for generating tourist dollars for National Parks is unrivaled.
Above all else, in a world of shifting baselines, they show Tsavo as it was – and what it could be again.
Recently, we returned to Satao. It was a month since his death, but the grass was still tinged green from the rainstorm that drew him there; the vegetation still strewn with Ipomoea flowers. A dead Comiphora nearby had collapsed under the weight of vultures. A tuber he’d been digging up was still exposed, but had sprouted soft, green, downy leaves.
Satao had always belonged to Tsavo’s soil and, slowly, he’s returning to it – fly and beetle larvae have worked their magic. Their dry pupal cases swirled, chaff-like, in the wind – they had collected in the lee of his skull. A brown-veined white butterfly rocked to and fro in the grass. Despite the wind, there was a stillness there.
It will take a year or two for Satao to be subsumed and for the grass to grow again – when it does it will be lush-green vivid. Each season, its fresh growth will mark where he lies – then, perhaps a decade hence, the nutrients exhausted, its colour will fade back to Tsavo.
I think a lot about Satao – but what brings a smile, is the thought that somewhere out there, unknown and unnoticed, is a young elephant, whose tiny tusks are an inch or two longer than others in his age group.
We’ve probably driven past him countless times, seeing him merely as a calf in a female herd.
We may not notice him for another three decades, but there will come a time when his tusks, like those of his father, start to glint through the heat haze – and mark him out as a future giant ‘tusker’. I just hope that his world will be a safer place.
© Mark Deeble & Victoria Stone and A Wildlife Filmmaker in Africa, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Mark Deeble and A Wildlife Filmmaker in Africa with appropriate and specific direction to the original content.