For any wildlife enthusiast heading to Africa on safari, the ‘Big Five’ – lion, leopard, rhino, elephant and buffalo – will likely top their wildlife wish list, alongside a wide supporting cast of other species to aim for.
The modest straw-coloured fruit bat probably wouldn’t make the top 100 for most travellers, says Mike Dilger, yet there are countless reasons why this little winged mammal is deserving of far more attention.
During October, hundreds of thousands of these bats descend from across sub-Saharan Africa to Zambia, where they spend a few short months roosting in a small patch of swamp forest in Kasanka National Park. It’s thought that the bats are drawn to the country by the massed fruiting of several tree species at the beginning of the wet season.
Part of the megabat group and with a wingspan topping an impressive 80cm, the straw-coloured fruit bat is one of Africa’s largest species, second in size only to the hammer-headed bat. The females’ fur is typically straw-coloured, while that of the slightly bigger males carries a brighter orange hue.
Numbers build steadily in Kasanka from mid-October, and the bats soon settle into a 24-hour pattern. They spend the day roosting in trees, hanging from the branches like umbrellas on a hat stand. As dusk approaches, they slowly rouse themselves, then lift off to form a huge swirling mass above the canopy before radiating out to feed. Having spent the night consuming the equivalent of their own bodyweight in fruit, the foragers stream back to the sanctuary of Kasanka at dawn.
Their landing technique is distinctly less than graceful. The bats fly up to a branch and grab it, then swing round to ensure their heads are pointing downwards. With so many of them entering the roost, hanging space is quickly taken, and any latecomers must attempt to cling on to a neighbour. Occasionally, a branch will break under the bats’ combined weight – snakes and lizards lurk below to claim those unable to quickly recover from their impromptu tumble to the forest floor.
How far do the bats travel?
sBeing adept flyers, the bats are capable of covering considerable distances during their nightly foraging missions – each a round trip of around 100km – and also when migrating to and from Kasanka at the beginning and end of each season.
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The sheer number conducting this annual pilgrimage makes their collective journey one of the largest mammal migrations in the world. Exactly where the bats spend the rest of the year is unclear, but most individuals that have been GPS-tagged in Zambia appear to travel to the Congo when the colony breaks up in late December.
The bats' crucial role in forest regeneration
Fruit bats play a crucial role in forest regeneration, something that is only now being fully appreciated. If each bat weighs around 250g, then a million bats are theoretically capable of consuming up to 250 tonnes of fruit each night, making them prolific dispersers of seeds.
As consumers of nectar, they are also key pollinators, not only of many tropical forest plants, but also valuable crops. Cashews and mangos, for example, are utterly reliant on bats to complete their life-cycles. These winged conservationists can even contribute towards the maintenance of many tree species’ genetic diversity, enabling gene flow between isolated patches of forest in what has become a highly fragmented landscape.
Despite the bats’ crucial contribution, deforestation and human-made fires across sub-Saharan Africa remain a constant threat. This is where ecotourism plays a vital role – visitors contribute to the local economy and can help to raise the profile of both the bats and their forest home. So, why not add the straw-coloured fruit bat to your African safari itinerary, making it a ‘Big Six’ instead?
