The Bull Shark

Meet the world's deadliest shark - the bull shark. The bull shark is known for its aggressive behavior and is even known to attack humans because it swims in shallow water where humans swim. However, this doesn't happen very often. Last year, there were only five recorded shark attacks - two by great white sharks and three by bull sharks. Bull sharks are found worldwide in warm, shallow waters along coasts and in rivers. The deepest water bull sharks swim in is less than 65 feet deep. 

The name bull shark comes from the shark's stocky shape, broad, flat snout, and unpredictable behavior. Bull sharks have small eyes because they often live in shallow, muddy water where eyesight is not that useful for hunting prey. However, studies have confirmed that bull sharks can see different colors of mesh netting underwater and tend to stay away from nets of bright colors. They grow to be 6.5 to 10 feet long. 

Bull sharks eat a large variety of animals, from fish and sea turtles, to birds, dolphins and whales. Bull sharks are known for bumping their prey before attacking. They swim rather slowly, but are agile and quick when chasing prey. Bull sharks are known by different names, such as the Zambezi River shark or the Nicaragua shark.

The bull shark belongs to the species of requiem sharks, along with blue sharks, lemon sharks, tiger sharks and reef sharks. Bull sharks living in the Amazon give the Amazon rainforest a bigger number of species of animals than most rainforests. Predators of bull sharks include saltwater and Nile crocodiles, some larger shark species, and humans. Their conservation status is vulnerable. 

Cool Fact: Bull sharks can live in both salt and fresh water and can travel far up rivers. They have even been known to travel up the Mississippi River as far as Illinois - about 700 miles from the ocean!

The Sperm Whale

Meet the world's largest carnivorous creature - the sperm whale! The sperm whale is so tough it can even take down one of the other largest ocean creatures, the giant squid. These two giants have great battles that rarely anyone has ever seen. Only some scientists have been lucky enough to see it. 

Sperm whales have typical names - males are called bulls and females are called cows. Females stay with their young while the bull goes hunting. The bull usually brings back larger food, such as giant squid and colossal squid. Young bulls often form groups but become more solitary as adults. Sperm whales use echolocation to communicate and are very loud! The sound from a bull sperm whale is loud and powerful enough to knock down a small house! Sperm whales can measure up to 65 1/2 feet long and live for up to 70 years! Sperm whales can be found in all the oceans from the poles to the equator. 

The sperm whale can stay underwater for two hours before running out of breath. It lifts its tail high above the water before plunging down after prey. This helps it get into position. Sperm whales are very deep divers, going about 10,000 feet under water! That is one of the deepest-diving animals! They travel so deep that they can sometimes go to the Mariana Trench, the deepest trench on Earth. When whales such as sperm whales go under water, their heartrate slows and blood flow to the skin stops so that it can flow to vital organs for longer. Scientists think that their wrinkled skin helps them dive deeper. 

Other whales, such as blue whales, humpback whales, bowhead whales, fin whales and gray whales are baleen whales, which means they eat plankton that filter through their brush-like teeth called baleen. But sperm whales belong to the family of toothed whales, which also includes all dolphins and porpoises, beluga whales, pygmy sperm whales and narwhales. Toothed whales eat fish and other animals. It is very rare to see them eat plankton. Sperm whales have huge heads to hold their 50 enormous teeth!

Sperm whales used to be in danger from hunting for their oil. But this is not happening as much today because of protection of these whales!

Cool Fact: Sperm whales have the largest brains of any creature on Earth - more than five times heavier than a human's!