Of all animals, definitely humans! But the most dangerous to us would be mosquitoes, they kill more humans than any other animal. If you were thinking of something larger, hippos have a pretty bad reputation for killing thousands of people a year – never get between a hippo and water, it will run straight through you!
Agreed with Joanna and Suzanne – Homo sapiens is very dangerous! Just to add that Giant pandas are also quite violent despite their immense reputation for being cute, peaceful and sweet. Such good reputation has however been helpful to protect the species, which is very endangered, so let’s not make a big fuss of it (just don’t ever get too close to one)!
I agree, it has to be humans. If your question was ‘what the most dangerous living thing’, then I’d probably say a virus, like ‘flu which can kill millions. But for animals, well in Africa Buffalo and Hippo kill more people every year than lions….I disturbed a big male hippo once while I was canoeing in a river on my own in Kenya – he went down under the water and I could see water bubbles slowly moving towards my canoe…I was so scared! I paddled so so fast to get away!