The common hippopotamus (Hippopotamus amphibius) is a herbivorous, semiaquatic mammal found in sub-Saharan Africa. The second largest population of hippopotami lives in Tanzania, numbering between 20,000 to 30,000. Although hippos are not carnivorous, and therefore not hunters, they aggressively protect their territory and often attack boats or people who encroach on their space. Despite their harmless appearance, hippos kill nearly 100 people per year in Tanzania, according to Mary Fitzpatrick, author of "Lonely Planet Guide: Tanzania."
The black mamba (Dendroaspis polylepis) is the largest venomous snake in Tanzania, averaging 8 feet in length. Because of its aggression, speed and the toxicity of its venom--which has a 100 percent fatality rate without proper antivenin--the black mamba is one of the most feared animals in Africa. In Tanzania, the black mamba is second only to the puff adder in causing human fatalities, according to Johan Marais, author of "Snake Versus Man: A Guide to Dangerous and Common Harmless Snakes of Southern Africa."
The lion (Panthera leo) is the keystone predator in Tanzania, found predominantly in the southern half of the country. Although run-ins with lions are preventable, instances of lion attacks have increased dramatically in recent years in Tanzania. In the past 15 years, there have been more than 800 attacks, resulting in 563 deaths and over 300 injuries, according to National Geographic Adventure magazine.
Most frequently found in dry grasslands and open savanna, the common puff adder (Bitis arietans) is a major hazard for those living in Tanzania. Because of their natural aggression, toxic venom and high numbers, the common puff adder is responsible for more deaths than any other snake in the country. Most fatal bites occur when individuals accidentally step on a resting adder, since they are incredibly difficult to see when lying still.
By far the most dangerous animal in Tanzania is the mosquito, which causes 100,000 to 125,000 deaths per year through the transmission of malaria, according to the Malaria Journal. Although not all mosquitoes carry malaria and other parasites, because of their vast numbers the likelihood of encountering one that carries disease is increased. Despite aggressive attempts to eradicate or diminish their numbers, mosquitoes remain numerous and are considered by epidemiologists to be the most dangerous animal in Africa.
