The Serengeti Great Migration Part 3 - River Crossing Season

01 July 2017

An introduction to the Great Migration's River Crossing Season

Our young wildebeest is now halfway through its first ‘Migration’. Having moved up through the Serengeti’s Western corridor the herds now move through Lobo in the northern heart of the Serengeti and into their dry season grazing grounds of the northern Serengeti and Maasai Mara. It is now that they face the major obstacle of their migration; the river crossings of the Mara River. Over the next few months, they may well cross the river a few times as they follow localised rainfall and search out the areas best grasses. With high banks and hefty crocodiles lying in wait, the herds often panic turning a calm, peaceful herd into splinter groups of sheer chaos. This is one of Africa’s most exciting wildlife events.

Where is the Great Migration located and why?

It is very common that the entire of the southern Serengeti receives no rain throughout Tanzania's dry season. However, the northern Serengeti and Maasai Mara have a macro weather system that's dictated by the vast expanse of Lake Victoria. The ebb and flow of the moon provides rainfall throughout this period whilst the Ololoolo Escarpment running along the western side of the Mara draws in further rain clouds that tend to focus the herds to the western part of the region. This is backed up by satellite data we have that clearly shows the herds focusing on the areas around the Mara River.

The Mara itself is in fact a relatively 'young' habitat compared to the Serengeti; a poor grazing area in comparison to the southern and western Serengeti. The reality however is the herds have no choice but to spend the dry season in this region. The major obstacle for the herds, and the major draw for tourists, is the Mara River around Kogatende and the Lamai Wedge on the Tanzanian side, and the paradise plains area of the Maasai Mara in Kenya. Fed by rainfall on the Mau Escarpment to the north the Mara River flows continually throughout the year and provides a much greater challenge than the Grumeti River found further south in the Serengeti itself.

The herds will use specific crossing points every year, and will cross to and from both sides of the river in search of good grasses. There is an argument that the herds cross north in July/August and south again in October. To an extent this is true – major crossings do happen at the beginning and end of this season - however just by looking at the Mara River on a map you can see what happens throughout August, September and October. The herds are moving around the entire region following rain and fresh grasses - north, south, wherever the rain is. The river will be in the way a number of times over this period!

Remember, every year and every day is different to the next. Be patient.

Not only is their movement dependent upon the areas rain and subsequent grazing, but wildebeest are unpredictable themselves. I have seen huge herds wait on the rivers edge for two days, literally testing the water, and never actually cross! The river is their major obstacle throughout the entire year (arguably the entire life of a wildebeest!), and they are inherently scared of crossing. Huge crocodiles lie in wait so you can hardly blame them for being cautious. However be patient, treat the herds as the wild animals they really are and you could well witness a crossing that will without doubt be one of the most amazing wildlife events you could ever witness.

As much as the timing is unpredictable, over a four night stay I would be surprised if you don’t see at least one crossing anytime from the 15th July through to the 1st November. In my experience the question is not when it will happen, but how big the crossings will be. Travel outside of this time period and you do take something of a risk. However you may well be lucky with a heavy crossing, every year is different from the next, and the northern Serengeti will certainly be quieter in terms of other travellers.