Sharks are often seen as unsophisticated and mindless. They are often portrayed in the media as mindless killing machines. In reality, sharks are one of the most smartest creatures on the planet. In fact, it could be said that they possess a degree of intelligence comparable to that of a dolphin. 

Megalodons are the largest sharks of all time, but basking sharks are the second-largest modern-day shark (also fish). However, both sharks are fascinating predators, and although one was a vicious carnivorous, the other one is a filter feeder. Still, there are certain fundamental ways in which both sharks are different.

Bull sharks and great whites are touted to be dangerous, man-eating animals. The great whites are bigger and more powerful. However, bull sharks are considered deadlier and more aggressive since they swim near the surfaces and coastal regions as compared to great whites that occupy open oceans.

Shark whales are touted as the largest species of the fish family whereas blue whales are the largest living animals on Earth. While shark whales are stouter, blue whales have a leaner appearance. Besides, shark whales have a blunt snout as compared to the pointed cone-like snout of blue whales. 

Sharks are mortal, and they die for various reasons, the most common of which is being hunted. Shark fatalities can be caused by various factors, some of which are natural, while humans cause others. As a result, even though they are at the top of the food chain, these fish are not inherently safe.

Sharks, like other fish, do not blink in the same way that humans do. Sharks, on the other hand, blink uniquely. This is because they have thin membranes over their eyes, called the nictitating membranes, which act as protective eyelids. However, nictitating membranes are not found in all sharks.

Most sharks cannot survive in freshwater for long. Because of osmotic pressure, their kidneys would burst if they remained in freshwater, which has a lower salt content than seawater. Even though they may be able to live in freshwater, they will not thrive like they do in salt water.

Sharks usually do not have any natural predators, but sometimes, smaller shark species are preyed upon by orcas and large sharks. In some instances, sharks are also attacked by dolphins. Sharks, in turn, prey on invertebrates, fishes, smaller sharks, and penguins. Some sharks also prefer eating plankton, algae, and other plant-based food items. 

Sharks have eye anatomy comparable to that of humans, and they have excellent vision. However, their ability to see objects is contingent on several conditions. Sharks, for example, have better eyesight in low light. They can also adjust their field of vision as needed.

Sharks, like human beings and other mammals, have eyelids. However, some shark species have three eyelids, which makes them different from humans. This third eyelid acts as a protector against potential abrasions and also keeps the shark’s eyes moist.