Mara River Crossings

Assembled from 19 blocks · 2 evidence · 28 related

1. Story
2. The mass fording of the Mara River by wildebeest and zebra during the northern phase of the circuit, concentrated between roughly July and October and repeated in both directions as herds oscillate across the river rather than crossing once. Mortality is real and measurable — an average of about 6,250 carcasses and 1,100 tonnes of biomass a year, equivalent to roughly ten blue whales — but it is a small fraction of the migratory population, and the drowned animals form a substantial nutrient subsidy to the river's food web. The crossings are the migration's most photographed moment; they are not the process that sets its population size.
3. Knowledge
4. Mara River
5. Mara River Crossings
6. Connections
7. Mara River
8. Mara River
9. The herds cross the Grumeti River in the western corridor
10. The Mara River crossings
11. Blue Wildebeest (Connochaetes taurinus)
12. Maasai Mara National Reserve
13. Serengeti National Park
14. Mara River Crossings
15. Mara River Crossings
16. The Mara River crossings
17. Evidence
18. An average of about 6,250 wildebeest carcasses and 1,100 tonnes of biomass enter the Mara River annually, with mass drownings in at least 13 of 15 monitored years, forming a major nutrient subsidy to the river food web
19. Dry-season food supply, not predation, regulates the Serengeti wildebeest population — demonstrated across the post-rinderpest irruption, the 1977–1993 plateau and the 1993–94 drought die-off