Shark dorsal fin is a fin found on the backs of fish. Though most commonly seen on sharks and whales, this type of fin can be found on many different species of fish, including cod, halibut, salmon, tuna and even coral. 

Bull sharks are known as one of the most dangerous species of shark in the world because of their aggression. They are considered to be one of the top three most dangerous species of sharks and have caused many injuries to both animals and humans that have come into contact with them. 

Sharks have pectoral fins on either side of their body, just behind the head and front fins, which help propel them through the water. Pectoral fins are small, paired fins found on the sides of sharks and rays. The pectoral fins are homologous to the arms of humans and other mammals.

Sharks swim very fast. They are the fastest fish in the oceans. Sharks have been swimming with humans for centuries. Although the shark’s speed depends on the species and size of the shark, they typically swim between 1-10 miles per hour (1-6 mph). Some shark species can reach speeds of up to 25 miles per hour (15 mph) when needed.

 Some sharks can indeed jump. In fact, sharks have been known to leap as high as 15 feet into the air, though usually the height doesn’t exceed three or four feet. They don’t use this tactic often, and it mainly occurs when a large shark has its sights set on an especially desirable meal and doesn’t feel like waiting until it swims by itself, which could take hours or even days in some cases.

Among their many other amazing adaptations, sharks are best known for unique tongues. The mouths of sharks contain structures resembling tongues. Unfortunately, they are not true tongues. These are bony projections in sharks’ mouths, also known as basihyals. They look like tongues while being not tongues at all. This is probably because a shark’s taste buds aren’t located on its tongue. 

Sharks only have inner ears which allows them to hear. Their ears are nothing like what we humans have though. They don’t have an outer or middle ear but they do have an aural cavity. This cavity is connected to the mouth and can detect low frequency vibrations. 

The gills of some sharks require constant movement in order for the water flowing over them to provide oxygen, but some sharks can move water through their respiratory system by pumping back and forth with their pharynx. They can therefore rest on the seafloor while still carrying on with their breathing.

A killer whale lives on average for 30-50 years in the wild. The oldest one is between 65-80 years of age. Studies suggest female killer whales outlive male killer whales possibly up to 20 years longer. However, when in captivity their average lifespan is reduced.