Do All Sharks Swim?

Epaulette sharks, named for the prominent black spot behind their pectoral fins, are unique in the shark world. They make their homes among shallow coral reefs and tidal pools around Australia, in water that is barely deep enough to cover their bodies. Although epaulette sharks can swim, they often prefer to walk along the seabed, looking for food, moving along by wriggling their bodies and pushing with their fins.

While other sharks must head for deep water, the epaulette shark exists quite happily in the oxygen-depleted shallows by slowing its breathing and heart rate.

Walking with the sharks:

• The epaulette shark is a small species, usually less than 3.3 feet (1 m) long. It has a slender body, a short head, and broad, paddle-shaped fins.
• Its coloration provides camouflage against predators, and the "epaulette" spot is thought to mimic the appearance of a large eye, serving as a distraction for some would-be attackers.
• The amount of dissolved oxygen in tidal pools can fall by 80% or more overnight. The epaulette shark can survive for hours with very little oxygen.

Frequently Asked Questions

Do all sharks need to swim constantly?

Not all sharks need to swim constantly. While many species, like the great white shark, must keep moving to push water over their gills for oxygen, others, such as nurse sharks, can pump water over their gills while resting on the ocean floor. This adaptation allows them to conserve energy and ambush prey.

Can sharks swim backwards?

Sharks are unable to swim backwards due to the structure of their fins. Their pectoral fins are not flexible like those of bony fish, so they cannot achieve the necessary motion to move in reverse. If a shark needs to retreat from something, it must turn around and swim away.

How fast can sharks swim?

The speed of sharks varies among species. The shortfin mako shark is renowned for its speed, capable of swimming up to 60 miles per hour in short bursts. On average, sharks swim at a more leisurely pace of 5 miles per hour, which is sufficient for their hunting and migration needs.

Do sharks ever stop swimming?

Some sharks do stop swimming. Species with buccal pumping can rest on the seafloor and still breathe. However, obligate ram ventilators, like the great white, must swim continuously or they risk suffocation. These sharks have evolved to even swim while sleeping, utilizing parts of their brain to maintain movement and breathing.

What happens if a shark stops swimming?

If an obligate ram ventilator shark stops swimming, it cannot draw water over its gills, and thus, cannot extract oxygen from the water. This can lead to suffocation. However, not all sharks face this risk, as some have the ability to actively pump water over their gills while stationary.

Do sharks swim in all depths of the ocean?

Sharks inhabit various depths of the ocean, from shallow reefs to the deep sea. Some species, like the scalloped hammerhead, are often found in coastal warm waters, while others, such as the Greenland shark, can be found in the cold, deep waters of the Arctic Ocean. Their distribution is largely dictated by their specific environmental preferences and prey availability.