Can you imagine walking from San Francisco to San Diego every year during the summer? Looks like, when we have been sitting back, revelling in the pride our knowledge and technology, a group of equestrians have been hoofing 311 miles (close to 500Kms) every year for the search of greener pastures, water and less harsher living conditions.
What is migration?
Migration is a yearly event that takes place during a particular time of the year, especially the onset of summer or winter. During this event, a group of animals of a particular species gather together in large numbers and fly or walk from one part of the land to another. This is also seen among fish, especially salmon and eels which travel from salt water to fresh water to lay eggs and back. Mostly animals and birds migrate for the search of pleasant living conditions to suit their survival and breeding and also in the search of richer food and water sources. Migration is a periodic movement of a group of animals from one region to another.
Why do zebras migrate?
Each year around 300,000 zebras along with other grazers gather up the young and start their tedious and trying journey across the river plains along a direct north-south axis. The wilds of Africa present these grazers with one of the toughest surviving conditions in this world. Every resource is transient and animals must always be on the move just to fulfil their basic needs of survival.
What is the route of this migration?
One of the longest recorded migrations undertakes by zebras is along the Chobe River Floodplains. The herds prefer to spend the dry seasons on this river basin as it serves as a good source for water and grass. But as the rains start to come they keep moving south towards the Nxai Pan National park. This journey is several weeks long and especially difficult for the young ones. The herds spend considerable amount of time, months at a stretch, grazing on the Nxai grounds before returning to Chobe floodplains again.
What do the researchers say?
According to Robin Naidoo, the lead researcher of the team who spent 2 years studying the migration pattern of zebras across the great plains of Africa, state,” the straight route followed by the herds were rather unusual. It almost felt like they were following a straight north-south direction across the river plains. But the distance covered by these zebras was completely unexpected. They covered 311 miles within a span of weeks. People were completely ignorant of the fact that something of this magnitude was occurring each year in some part of this world”. The scientists and researchers from WWF and ministry of environment and tourism, Namibia knew has a whiff of something odd occurring, as “the herds would simply disappear from Nxai National Park during the summers and spring up on the floodplains of Salambala each year. But something this huge was beyond their imagination”, says Naidoo.
What makes this migration unique?
“There were several other similar destinations nearby the floodplains where they graze during the summers, however some unknown reason causes these herds to choose a far away destination like the Nxai National Park each year”, ponders Robin Naidoo. But researches on animal migration suggest that herds are more likely to stick to their traditional routes to the closest meter even if there have been changes in water resources and grazing grounds over the years. “Since zebras are social animals it is very much possible that they follow this route as a result of transmission of knowledge about landscape and routes over the generations”, concludes Naidoo with his research team.
There may also be a genetic basis for such a bizarre route and distance, but yet more is to be found out from further studies conducted on the herds of zebras that undertake this arduous journey every year for survival.