The bull shark (Carcharhinus leucas) is one of the more common large shark species that can be found in many coastal areas in warmer waters. They are also known to be one of the most dangerous species of shark to humans, and also have a unique hunting method which most other sharks are incapable of.
In appearance the bull shark is very heavily built, and has a blunt rather than pointed nose, unlike most sharks which tend to be long and slender. Bull sharks typically reach around 2 meters for males and 3.5 meters for females, and reach weights of 200lbs and 700lbs respectively. This is very heavy for such a short shark, and bull sharks are known more for their strength than for their speed in open water.
Unlike most sharks, the bull shark is capable of surviving in both salt and fresh water, meaning that they are often to be found inland in streams and rivers. They have also even been known to find their way into inland lakes such as lake Michigan on occasion. Because of this, bull sharks have to be adaptable enough to hunt a large range of prey species, and to be successful at catching them.
Although capable of living in either type of water, bull sharks tend to move between the two frequently most of the time. The only noticeable effect of being in fresh water for the bull sharks is that they have to urinate much more frequently, and so their kidneys have to work harder than usual.
As a result of the fact that it encounters a broad range of territories and prey, the bull shark will generally eat almost anything in the water with it. Bull sharks are thought to be responsible for more attacks on humans than any other type of shark, and will also eat other sharks, rays and fish. They have also been known to attack animals crossing through rivers, sea birds and juvenile crocodiles.
To kill their prey, bull sharks often charge into it with their head to stun it before biting. This method is known to be particularly effective for stopping faster prey from simply swimming away after having been bitten. The bull sharks main strength tends to lie not in its speed, but in the fact that it can ambush its prey in murky river waters, and stun it before it can react. Also unlike many sharks, bull sharks will readily swim in only a few meters of water, allowing them to chase down prey other sharks would have to leave alone.
Another reason that the bull shark headbutts its prey before biting is because they have very poor eyesight, and instead rely on their sense of smell to locate their food. Because of this, they often have no idea how big something is until they actually hit it. This may be one of the reasons why bull sharks are never afraid to attack things which are of comparable size or sometimes even larger then themselves.
Although bull sharks have very few natural predators in most cases, they have been known to be killed and eaten by crocodiles in shallow water. The only other species which they tend to avoid is elephants, who will often swim several miles out to sea and through rivers around Africa. Although of course avoiding contact with elephants is a good survival trait for any predator.
When there is no large prey around for the bull shark, then they will also resort to eating mollusks, echinoderms (sea stars etc), crustaceans and turtles. For most sharks these kinds of prey aren’t worth bothering with. However because the bull shark can swim over such a wide range of territory, there aren’t always optimal sized species for it to feed on.
The bull shark is unique for a number of reasons amongst most sharks, one of which is that it is generally a solitary creature, and will only seek out other bull sharks for mating purposes. At any other times bull sharks are very territorial, and although they travel widely, they will not tolerate other bull sharks, or other large sharks for that matter in their immediate vicinity.