During the great drought of 1970-71 in Tsavo East National Park, Kenya, more than 5000 elephants have starved to death with a full stomach. – Why have they starved to death with a full stomach? After how many months of continuous drought have they died? How much crude protein did the food in their stomachs then contain? Which groups of elephants died first?
Daphne Sheldrick, wife of the late chief game warden of Tsavo-East National Park, in Kenya, was herself there, when the great drought hit the park in 1970-71, and also in 1972. Her husband had served there already as a game warden for some 24 years. Mrs. Sheldrick writes about the elephants of Tsavo-East:
"Those elephants, whose dry-weather territory coincided with the minimum falls of rain during this time, suffered from a lack of protein in their diet and died in large numbers where they were, making no attempt to move elsewhere in search for better feeding grounds. This limited dry-weather movement of elephants was very clearly illustrated not only in the lower reaches of the Galana river and around Aruba dam, but also in a very narrow drought-stricken belt on the Tiva river in the extreme north of the Park, which happened to miss most of the rain. There, many elephants also died from malnutrition, although, had they moved five miles either up or down-stream they would have found a more plentiful supply of food. If a certain area receives one third or less of its normal rainfall for any length of time, the protein value of the grass and available browse is so low that the elephant and rhino who are resident in that particular place in the dry season suffer as a result." (1972:27).
Which species of animals suffered most in this great drought?
Mrs. Daphne Sheldrick: "The two species most affected by these periodic droughts in Tsavo East have been the elephant and the rhino. These two particular species are probably the most susceptible to drought conditions, due simply to their physiology. Whereas most other herbivores, many of which are ruminants, can extract the maximum benefit in terms of available protein from what they eat, the elephant and rhino have been endowed with a much less efficient digestive system, and as much as six per cent protein have been recorded as having passed in their droppings. Furthermore, due to their bulk, they have also to rely on protein rich browse to supplement their diet in the dry season, when the grass is very dry.
"Only the lack of rain, and the subsequent absence of vegetational regrowth coupled with the low protein content of the available browse caused the death of the elephant and the rhino in the drought of 1970-71, for most deaths occurred actually alongside, or within reach of water; along river banks and on game trails leading to water, which, after all is understandable, for once the animals became emaciated and weak, they chose to remain close to water, being unable to cover great distances.
"The long rains, although inadequate, brought a temporary reprieve, but deaths again started to occur in the stricken belt towards the end of August 1971, and escalated as the dry season wore on. Cows and calves were affected most. Very few bulls suffered, being more independent and mobile, unencumbered by feelings of responsibility for the young and for each other. The calves, weakened and tired, held up the cow herds until the adults too suffered the same symptoms; a rapid decline in condition and eventual death from malnutrition. The toll mounted with each day that passed.
"Quite obviously, the elephant and rhino do suffer acutely during times of drought, but this suffering is more psychological than physical. This was demonstrated clearly in Tsavo where groups could be observed fast asleep under the shade of trees, slowly becoming weaker and more lethargic until they could not find the strength or the will, to leave the permanent water in search of food, and finally collapsed and died beside it. Postmortem examinations revealed that although their stomachs were full, the protein value of their contents was as low as two percent.
"The elephant in the eastern corner of this Park have been drastically reduced. The number that have died has yet to be accurately assessed, but it is likely to be in the region of one-third of the Tsavo-East’s population. The fact that elephants appear to be so localised in the dry season is probably very fortunate, and no doubt ordained by Nature to protect the environment from the depredations of a large roving population that could eventually eat themselves out of existence, cleaning out one area and then systematically moving onto the next." - Sheldrick, D. (1972:27, 28).
Norman Meyers of the School of Forestry and Conservation in Nairobi, Kenya, and of the University of California, at Berkeley, says about the great drought in Tsavo East: "The environment could be undergoing not only fundamental modifications but drastic deterioration, making it less able to support Elephants and a range of other creatures – particularly Black Rhinoceros (Diceros cornis). During the drought the Black Rhinoceros population fell by several hundreds – an aspect of the die-off which has been little mentioned.
"The Elephant is at some disadvantage as compared with most herbivores in Tsavo, with its larger bulk, its greater absolute intake of food per day, its dependence of woody vegetation for at least part of its diet, and a monogastic system that passed food through its gut in relatively undigested form. Something of the same difficulty faces the Black Rhinoceros, which is not so much in trouble as the elephant but is the only creature at Tsavo to be dying in fair numbers." (1973:123:128).
African savannah elephant-cow with small calf, charging. Both are spreading out their ears, to intimidate their foe. In her right ear there is a hole. From: Grzimeks Enzyklopädie (1987:463) Vol. 4.
How many elephants died
How many elephants have starved to death during the great drought of 1970-71 in Tsavo East? Which groups were affected most?
Timothy F. Corfield of the Tsavo Research Project, Kenya National Parks, counted the elephants that had died in Tsavo East during the great drought of 1970-71. He estimated that about 5,900 elephants died during the drought. Most carcasses lay near permanent water. In the hinterland, they were sparse or absent. Mostly cows and calves and older animals died, few adult males. Actually counted were 4,764 carcasses. To this number, he added those carcasses that had disintegrated in the meantime. – Why have they died?
T. F. Corfield: "In accounting for the mortality, it is probable that the high rates were due to widespread starvation. Autopsies carried out on two fresh carcasses, an adult and sub-adult female, showed no evidence of disease or abnormal parasitic infestation.
"The mother-calf bond is a strong one, and adult females are therefore limited in their search for food to the distance attainable by the youngest members of the social group. As the elephants cannot survive without drinking, the food supply near water was progressively reduced. The search for food therefore became ever more arduous, and by the time the youngest had collapsed and died, accompanying adult females were perhaps irretrievably weakened. The reluctance of adult females to leave their young is well documented.
"Adult males, in contrast, with their greater independence, were perhaps freer of family restraints and were consequently less affected by the harsh conditions. This could also apply to immature male elephants who being more independent than their female siblings, were able to forage more effectively. ... High mortality occurred during 2 consecutive years when both the average rainfall was low and the long dry season unusually prolonged. The former is important because of its effect on primary (= plant) productivity." (1973:339-368).
After how many months?
After how many dry months in a row have the elephants of Tsavo East during the great drought of 1970/72 starved to death with a full stomach? How much crude protein did their food contain during each one of these dry months, till they died? And at which intake-deficit of digestible crude protein and metabolizable energy have the adult and growing elephants during the great drought of Tsavo East died? - I have used here the monthly rainfall in the Tsavo region from 1969-72, published by T. F. Corfield (1973). That is from Lugard’s Falls, Sala, Aruba Dam and Ithumba.
And I have also used here the maps showing the above ground dry matter growing in the southern part of Tsavo East N. Park from 1969-1972, in J. Phillipson (1975). The results of my findings I have published in The Mammoth and the Flood, Volume 1, pp. 86-100. The deadly DCP and ME intake-deficit of these elephants and rhinos I have published in the next chapter of this volume. Here I just would like to mention, after how many continuous dry months these animals died.
African savannah elephant cow with her calf in the dry season, when the surface water is gone. She has dug here in the sand of a dry riverbed a hole, to find water. Her calf is standing now in this hole, sucking up the ground water, seeping up. Without these water-holes, which the elephants have dug with their tusks, trunk and front-hooves, the elephants would not be able to live there in the dry season, nor many other kinds of animals, not adapted to the desert. From: Grzimeks Enzyklopädie (1987:472) Vol. 4.
Lugard’s Falls
Lugard’s Falls lies some 30 miles from Voi and 2 miles below the junction of the Tsavo- and Athi river. – After how many continuous dry months have the elephants and rhinos died there?
1969: In 1969, Lugard’s Falls had only 2 dry months in a row: June and July. Elephants have, as far as I know, not starved to death.
1970: In 1970 it had not rained at Lugard’s Falls at all (or not enough) for three months in a row: from June to October. – Mrs. Daphne Sheldrick (1972:27) remarks about this: "The rain that fell at the beginning of 1970 was patchy and well below average in most areas, which gave us an inkling of what we could expect. The effects were felt towards the end of 1970 before the onset of the short rains, when about 300 young elephant calves and a few rhino died from malnutrition east of Lugard’s Falls.’
The whole Park was dry from June to October. In November it rained at Lugard’s Falls, but the rest of southern Tsavo stayed dry, according to John Phillipson’s plant production map for 1970. The elephant calves and rhinos, Mrs. D. Sheldrick informed me in her letter of February 25, 1980, have died between October and December 1970.
Result
1969: In 1970 at Lugard’s Falls, there were 7 dry months, from June till December. The elephant calves and rhinos were starving to death near Lugard’s Falls, in October to December, when there had been 4 dry months in a row (from June to September). During these 7 dry months, the hinterland within their reach was also too dry. It had not rained there either, and there was nothing to drink and no (or not enough) fresh, green food.
1971: In 1971 it had not rained at Lugard’s Falls at all (or not enough) during ten months in a row: from January till October. The elephants began to die, after there had been only 3 dry months in a row: from May till the end of July. During these 3 months, they were not able to leave their dry-season-range near permanent water, because the hinterland within their reach was just as dry. – In 1971, they died from the end of July till October. In November it rained, but the elephants, which were still left, were able to live on.
During the great drought in 1971 in Tsavo East, it had rained only a little at the northern tip of the Park. Hence the elephants were not able to leave their dry-season-range near permanent water for 4 months (from May till October), in order to search for fresh, green food somewhere else.
1972: In 1972 it had not rained at all (or not enough) near Lugard’s Falls for 3 months in a row: from June to August. That elephants have starved to death during this season has – as far as I know –, not been reported. In September it then rained a lot: 60 mm.
A Black rhinoceros at a pond of water, drinking. The rhino is only able to live, where there is water. They drink daily. During the dry season they often walk a long way to the next water hole. During the dry season they may be able to live up for up to two or three days without drinking water. From: Grzimeks Enzyklopädie (1987:622) Volume 4.
Sala
Sala lies at the eastern border of Tsavo East N. Park, toward Galana Ranch, south of the Galana River.
1969: In 1969 at Sala, there were 4 dry months in a row (from June to September). But there was rain south of Sala in August, producing up to 50 g/m² vegetation (dry matter). Thus, the elephants near Sala had only 2 dry months to endure, June and July. Elephants are not reported to have died.
1970: There were 9 dry months in a row at Sala in 1970, where no rain fell at all or only a few scattered showers: from February to October. The elephants near Sala in 1970 had to endure 5 dry months in a row, June to October. During this time, they were not able to move somewhere else, because the whole area (within their reach) was just as dry. They began to die in the 5th month, in October, after 4 months of drought. In November, they had again enough to eat, because 33 mm of rain had fallen, producing about 22 g/m² of dry above ground matter.
1971: In 1971, there were 7 dry months in a row at Sala: from May to November. After three dry months (May-July) the elephant began to starve to death (from August to November). November had only a little rain (13 mm). In July, only 17 mm of rain fell at Sala, in June 20 mm, and in May 15 mm, producing less food, than the animals needed each month. Thus, monthly aboveground plant growth lay for 7 months in a row – from January till November 1971 at Sala , below the 26.2 g/m² dry above ground plant matter, calculated by J. Phillipson for the area south of the Galana in 1971. When severe drought set in again in August, the elephants must have used up must of the browse. And fresh, green forage could not have grown much since the drought of last year.
From May till October, the whole area of southern Tsavo East was dry. Only in June of 1971 it had rained a little at the southern tip of the Park. In November it rained in the western and eastern area, but the middle stayed dry, or received only scattered showers. And the rain that finally did come then in November, came too late. Sala received about 13 mm, and the elephants kept on dying from the beginning of August till the end of November. In December it rained a lot, and the surviving animals had enough to eat again. In 1971, the elephants near Sala began to die from the 4th month onward: after 3 months of drought in a row. During this time, also the whole area within their reach was dry, so that they were not able to move elsewhere.
1972: June to August in Sala in 1972 were dry within their reach – three months -, but the elephants did not die in September, because then, 33 mm of rain fell, producing 22 g/m² of dry above ground plant matter. That was not quite enough. But it did rain then a lot in the southern part of the Park, producing up to 150 g/m² vegetation (dry matter). None are reported to have starved then to death. Result: In 1972, the elephants at Sala had to endure 3 months of drought – June to August. The whole area within their reach (walking distance) was then dry. None of the elephants are reported to have starved then to death.
Aruba Dam
The Aruba Dam was built in the Voi River, to provide the game of southern Tsavo East N. Park with drinking water during the dry season. It lies south of the Galana River and northwest of Tsavo West N. Park. Tsavo West is bordering in the southwest on Tanzania.
1969: At the Aruba Dam no rain fell in 1969 for 3 months in a row: from the beginning of May till the end of July. The elephants did not starve then to death, because in August, 32 mm of rain fell, producing up to 50 gram above ground dry plant matter. – If we study John Phillipson’s monthly plant production map for 1969, we see that in May it had not rained in the Park further north. Up to 25 g/m² above ground dry plant matter was growing there. If we do take the southern part of Tsavo East as a whole, the elephants then had only 2 months of drought in a row – June and July -. During these two dry months it had also not rained in other parts of the Park.
1970: In 1970, Aruba Dam had 8 dry months in a row, where it either did not rain at all, or where it rained so little that less food grew, than the elephants needed, from April till November. But the elephants died only during the last 3 months of the drought: from the beginning of September to the end of November. In December it rained a lot (78 mm). And the remaining animals were able to live on. In May 1970 it rained at the southern tip of the Park, producing up to 75 g/m² above ground dry matter. So the elephants only had to walk a few miles south, to find plenty of fresh green grass.
Southern Tsavo East in 1970 was only dry in a row from the beginning of June to the end of November. In those 6 dry months, the elephants were not able to leave their dry-season-site near Aruba Dam. They were using up the remaining grass and browse. Only in November 1970 it did rain; but this rain came too late. The elephants began to die after 3 months of continuous drought, from September to November.
1971: In 1971, Aruba Dam had 11 months in a row, where it either did not rain at all or where it did not rain enough, from May to November. The elephants died from August to November. The dry season began in January. So we may ask ourselves: Why were these elephants able to survive so long?
A glance at the monthly plant production map of southern Tsavo East will show us: In April, Aruba Dam received only a little rain. But further west and east, it rained a lot. Up to 200 g/m² of vegetation (dry matter) were growing there. They only had to travel a few miles east or west, and they would have found enough to eat.
If we consider the southern part of Tsavo East as a whole, the following picture emerges: In 1971, there were 6 dry months (from May to October). The animals had to stay near the river and to feed on the remaining grass and browse, close to permanent water. The longer they stayed, the more the crude protein of the remaining forage fell. The herds must have used up already a lot of the browse along the river during last year’s drought. Hence, not much suitable browse can have remained by now. The elephants began to starve to death with a full stomach, therefore, now already after 3 months of continuous drought.
1972: In 1972, Aruba Dam had 3 dry months in a row. In was raining then so little, that less food grew, than the elephants needed: from February to October. But the elephants did not starve to death now. – Why not?
The monthly plant production map of southern Tsavo East shows us: In March it rained in the southern tip of the Park. In April it rained further east, and in May, further west and east. The western area produced in February 1972 up to 150 g/m² above ground dry matter, and in May 1972, up to 200 g/m². September produced only about 2/3 of the needed food. But it did help, to keep the herds alive. They did not starve to death, after the whole area within their reach (walking distance) had been gripped by 3 continuous months of severe drought. Thus, Aruba Dam in 1972 was dry only in June, July and August.
Result
What have we found out now about the great drought in Tsavo East National Park, in Kenya, East Africa from 1969-72? We have looked briefly at the monthly rain and above ground plant growth from 1969-72 at Lugard’s Falls, Sala, Aruba Dam and Ithumba. We found out:
1. The normal dry season is there 3-4 months long. Enough fresh green grass is growing then per month. During the normal dry season, the elephant will stay in its dry-season-range near permanent water, near a river, lake, or swamp, feeding on green vegetation, mostly on browse and water-plants. The elephant is only able to live, where there is water. The dry-season food supply near permanent water will usually last till the end of the drought.
2. When the elephant has used up its food-reserves in the dry-season-range near permanent water, it will be able to survive the drought, by going into areas, where it as rained a short time ago. There, fresh, green grass is growing then. And the water holes and creek-beds are filled with water.
3. When the elephant has used up its food reserves near permanent water at the end of a long, severe drought, the hinterland within its reach (walking distance) is just as dry. And there is no fresh green vegetation and no surface water either. The elephant will have to stay then, where he is: near permanent water.
4. If it does rain enough nearly during such a severe drought, there will be surface water and fresh green grass, high in protein and low in fiber. The elephant will go there, if he is still strong enough.
5. If the elephant has become too weak during the long drought, it will just stay, where it is: near the river, lake or pond, until it collapses and dies – with a full stomach. The tusker will stay there, even if it should rain a lot nearby, and even if a lot of fresh, green grass, rich in protein and low in fiber, should begin to grow nearby, like in Tsavo East, during the great drought of 1970-71.
6. At Lugard’s Falls, Sala and Ithumba, in 1970, the elephants began to starve to death, after there had been 4 dry months in a row. During the next year of this drought, in 1971, they began to starve to death already after 3 dry continuous months. During this time, they were not able to move away from their dry-season-range near permanent water, because the hinterland was just as dry.
7. At Aruba Dam, in 1970, the elephant began to starve to death already, when there had been 3 dry months in a row. And at Ithumba, some of the elephants were also dying in 1972, when there had been only 2.5 dry months in a row.
8. In 1971, the elephants were starving already 1 month sooner than in 1970, because of two different reasons: (a) by then, they had become weaker. And (b) they had used up already much of their supply of browse (branches of trees and shrubs) near permanent water. During the second year of drought, they had to rely, therefore, already more and more on the freshly grown green grass. But this fresh, green grass was only growing, when it had rained enough.
9. The elephants and rhinos, during the great drought in Tsavo East N. Park, from 1970-72, have starved to death with a full stomach. It contained only dry brown grass and browse. This dry, brown food contained too little crude protein. Only 2% CP or more. These elephants and rhinos were starving to death with a full stomach, because the microflora in their intestines was not able to digest this coarse food anymore.
During the great summer drought, the elephant herd is staying near permanent water. From: Grzimeks Enzyklopädie (1987) Volume 4. Since the elephants have used up most of the grass and browse near the water, they must walk further and further into the dry hinterland, to find something to eat. Since the metabolic rate of the small calves is highest, they will get tired first and lay down, to rest. Its mother and other members of the cow-herd will try to lift it up again onto its feet. When the calf has become too weak, it will die. Most of the dry grass and the shrubs and trees there are gone. The elephants have torn the trees and shrubs down, to eat the twigs and the bark. Now nearly nothing is left and the calf has collapsed. Since the ties between the elephant mother and her child, and also with the other members of the cow-herd are very strong, these female elephants will also soon collapse and starve to death with a full stomach. They will starve then to death with a stomach, which is filled with dry brown grass and brush, too high in fiber and too low in protein. The elephant is still able to eat it; but is not able to digest it anymore, because the micro-flora in its digestive tract has become too week, or has died already.