The Great Migration & Changing Seasons in the Serengeti

By Courtney Suciu

Here in the U.S., as late summer gives way to early fall, it means back-to-school, colorful piles of fallen leaves and pumpkin-spice flavored everything.

But around the world, the changing seasons are experienced in a dramatically different way. Or, as British broadcaster and naturalist Sir David Attenborough (who just won his first Emmy for his narration of the series Blue Planet II*) more eloquently notes in the documentary program, The Great Migration¹:

The power of the sun drives the seasons, transforming our planet. Vast movements of ocean and air currents bring dramatic change throughout the year. And in a few special places, these seasonal changes create some of the greatest wildlife spectacles on earth.

Specifically, in the Serengeti this time of year ushers in the dry season and marks the end of the cycle known as the Great Migration. For predatory animals in the plains of East Africa, it means the concentration of grazing animals like the wildebeest dissipates and the food supply is diminished.

In this blog post, we join Attenborough to discover how one Ndutu lion pride struggles to survive.

As the plains dry up, so does the food supply

As early in the year as May, the rains begin to move north and the wildebeest follow. Attenborough explains, “Wildebeest are so in tune with the seasons that they can hear thunderstorms 50 kilometers away, and they home in on the scent of wet soil that carries the promise of fresh grass.” Over the next few months, the surrounding vegetation withers and the vast majority of grazing animals move out of the region.

However, Attenborough adds, “but lions are territorial. Each pride only controls a small area of grassland. They can only hunt the animals that come into their territory.” This lion pride includes four lionesses and seven cubs. By August, all of them are already weaken and underweight.

As the grazing animals have migrated away from the area, “the short grass plains are no longer a great place to be a lion,” Attenborough narrates. “For the lion pride living at the southern edge of these plains, in a place known as Ndutu, the test now is to survive until the herds return again.”

Seeking shelter and animals to hunt, the lions make a long trek for the woodland. But the journey proves too arduous for one sickly male cub who gradually gets left behind. “The lionesses simply cannot wait. If they don't keep hunting and eat soon,” the narrator explains, “they too will become weak, and then there'll be no hope for any of them.”

The struggle to keep together

Even when there is prey, the cubs are still too young to hunt for themselves, so their survival depends on keeping up with the adults. But by September, only two males remain with the pride; they are skin and bones.

Among the cubs who have gotten separated, a female, limping and missing patches of fur as the result of illness, finds her brother. In the distance, the lionesses cry out for young ones to return. However, “the pride will have to move to another part of their territory if they are to find food,” the narrator notes. “None of them have eaten for days, and now the chances of being reunited with the lost cubs seems remote indeed.”

October marks the peak of the dry season and the heat is searing. One of the male cubs who remained with the pride has died, but surprisingly, the female with patchy fur has found her way back. Attenborough observes that she “clearly hasn’t eaten for days” and her “chances of a meal have fallen even further” after a fire destroys the remaining grass and brush cover the lions use for hunting.

Matters are made worse when after a 40 year slumber the volcano known as Ol Doinyo Lengai (“Mountain of God”) erupts: “Vast clouds of volcanic ash drift towards the short grass plains, and the home of the Ndutu pride lions. Ravaged by fire, scorched by the sun, the plains now become shrouded in a layer of ash.”

The return of the rains, and the Great Migration

In November, the rains are overdue. The lions are desperate for relief. “But the winds are changing,” Attenborough points out, “a sign that the season is turning.”

It’s a sign the wildebeest recognize, and the herd begins moving south: “One and a half million wildebeest start their journey back to the short grass plains.”

When the rains finally come, they bring hope to the Ndutu lions as “fresh grass transforms the arid plains into the lush pastures that will lure the herds to return.” However, there is no guarantee the wildebeest will return to their territory.

The journey of the wildebeest can be as long as 1,000 miles – “one of the longest treks of any land animal on our planet” – as they follow the rain across the Serengeti. They’ll be joined in the plains with the greatest concentration of grazing animals anywhere – up to 3 million animals will ultimately gather here.

Over the next few months, the herds continue south and at last enter into Ndutu territory as the Mountain of God unleashes a column of ash, rich in minerals fertilizing the ground and discouraging the growth of trees: “its possibly the best grazing land in all of Africa,” Attenborough says.

It’s a phenomenon that people from around the world spend thousands of dollars to witness in person. In the past, according to The Daily Telegraph², the Serengeti (which means “the land that goes on forever”), used to be “bandit country, crawling with poachers,” now attracts more than 90,000 visitors annually on luxury safari expeditions, drawn by “the spectacle of the of the wildebeest migration – the greatest wildlife show on earth.”

As the cycle of the Great Migration begins again, the lions are “lucky enough to enjoy a time of plenty;” but Attenborough wonders: “Have the weak cubs managed to survive to witness the great return?”

They have. “The young male now has the beginnings of a mane. And though still limping, the female has grown new fur over her black patches,” he notes. “Now, at last, with endless food around them, the lion cubs have the time and the energy to play.”

For further research

Students and researchers can stream the rest of Sir David Attenborough’s nature documentary series Nature’s Great Events, along with the episode “The Great Migration” – and 67 other popular nature titles, including Blue Planet, Blue Planet II,* Frozen Planet and Life, with more to come! – through the BBC Landmark Video Collection.

The content in this database can be supplemented with text, video and primary source materials from the Environmental Issues Online collection as well as titles from Ebook Central:

Estes, R. D. (2014). The Gnu's World: Serengeti Wildebeest Ecology and Life History.

Gardner, B. (2016). Selling the Serengeti: The Cultural Politics of Safari tourism.

Hansen, G. (2017). Wildebeest Migration.

Kennedy, A. S., & Kennedy, V. (2014). Animals of the Serengeti and Ngorongoro conservation Area.

Schaller, G. B. (2009). The Serengeti Lion: A Study of Predator-Prey Relations.

Sinclair, A. (2012). Serengeti Story: Life and Science in the World's Greatest Wildlife Region.

Works cited:

1. 1. Bassett, P. (Producer). (2009). The Great Migration [Video file]. BBC Worldwide. Available from the BBC Landmark Video Collection.
   2. Jackman, Brian. "Serengeti Stampede, Poachers in Retreat." The Daily Telegraph, Apr 28, 2012, pp. 3. Available from ProQuest Central.