Since there have been about 450 million years since sharks and humans shared a common ancestor, and white sharks have been swimming in the ocean looking more or less the same for the past 16 million years, people tend to assume that sharks are primitive animals, missing the sort of specialization and development that “higher” and “more evolved” animals have. (For comparison, our genus Homo first appeared 2.5 million years ago, and modern humans appear in the fossil record only 200,000 years ago.)
But being an ancient class of animal doesn’t mean that sharks are less adapted to their environments than more recent species. Since their lineage parted ways with bony fish (and us), sharks have continued to evolve into the diverse species we know today, developing unique approaches to solving the problems of life.
Some of the white sharks’ adaptations are surprisingly advanced, such as giving birth to live young and body-temperature regulation, which most people associate with mammals. Even more advanced are the unique senses sharks have:
Sharks have sensory organs known as ampullae of Lorenzini, which are dark pores around their snouts that are sensitive to electrical fields. Behind these pores is a nerve that connects to the shark’s brain, relaying information about the electrical fluctuations around them. Here’s a closeup of a white shark’s ampullae.
The ampullae help sharks hunt by sensing the electrical activity in their prey’s body, such as heartbeats. Because of their strong ability to sense electrical fields, sharks are often attracted to metal and electrical devices, sometimes finding them more fascinating than bait.
Lateral lines are an extension of a shark’s sense of touch. They are a series of modified hair cells, which respond to tiny disturbances in the water around the shark. The lines run from a shark’s head to the top of its tail.
Sharks use the lateral lines to detect patterns in the water that suggest an injured or distressed animal. Sharks also combine lateral lines with their own swimming patterns to create an echolocation field, sensing the presence of animals from how the waves created by their own movement return to them.
Pit organs are shark’s most mysterious sensory organ. They are a group of hair cells around the gills and pectoral fins, which are believed to help a shark detect changes in water temperature and currents.
The more we understand about sharks, the harder it is to consider them “primitive”, and the only way to understand more is through research and conservation.