Cows
They may seem docile and slow-moving, but cows can become aggressive if they feel threatened when they have calves. They can charge, kick, or trample humans, causing severe injuries or death.
Rats
Many people have reported incidents of rats biting humans, and their sharp teeth can transmit diseases like rat-bite fever, which can be dangerous.
Hippos
A commenter wrote that they have powerful jaws and teeth and can easily overturn boats or attack humans who come too close.
Chimpanzees
They can also display aggressive behavior towards other chimpanzees if they feel threatened or there is competition for food or mates.
Cats
Cats are natural predators and can bite or scratch humans when threatened or provoked. Moreover, outdoor cats can transmit diseases to humans through scratches or bites.
Mosquitoes
Mosquitoes may be tiny, but they cause more human deaths than any other animal on Earth, a bunch of people confirmed that.