Largest gathering of mammals
Who
Fruit bat (Eidolon helvum)
What
5000000 - 10000000 total number
Where
Zambia (Kasanka)
When
2011

Each October, between 5 and 10 million straw-coloured fruit bats (Eidolon helvum) converge from all over Africa on Kasanka in Zambia for a six-week binge on ripened mangoes.