Scientific name: Carcharhinus leucas

Bull sharks are one of the coolest—but most aggressive—sharks in the ocean. The movie Jaws was even inspired by these lurking predators of the deep (although the shark in the movie was a great white). They can grow to 7 to 11.5 feet and often live in coastal waters, which makes them no small guppy in a big pond. They get their name, “bull shark,” from their flat, broad snout and their temperament—often described as a charging bull—but they aren’t mindless killing machines. They are the result of their environment and evolution, which took millions of years to arrive at the present.

Sharks in general aren’t out to get you. You are in their environment, and they act accordingly. Bull sharks typically live in shallow waters near shores, rivers, and estuaries, which are limited spaces. In tighter areas, they can be more territorial and more likely to see other creatures (including you and me) as intruders. In these environments, the water is usually murky, making it hard for them to see what’s in front of them. They are opportunistic feeders, which leads to an “eat first, ask questions later” attitude about their prey.

One of the coolest things about the bull shark is its ability to travel up freshwater streams inland. Bull sharks have a unique ability to regulate salt levels in their bodies through their kidneys and special glands. Most sharks need saltwater to survive, but bull sharks can adapt and maintain the right balance in freshwater too. This is called osmoregulation. But what's the point of leaving the wide-open ocean for the narrow straits of a river? One: less competition from other predators. Two: it’s a safe place to give birth due to the murky waters of rivers and the lack of other predators. And finally: because they can. Yes, it gives them a survival edge, but they also seem to do it just because. They’ve been found hundreds—sometimes thousands—of miles up rivers. One famous case: bull sharks were found in the Mississippi River all the way in Illinois.

The more we learn about the bull shark, the more impressed we become. This apex predator of the sea is not only a miraculous member of the shark family but also a testament to why sharks have dominated the oceans for millions of years.