Despite gaining their name from how often they sun themselves, basking sharks often mirror whales more than sharks. Basking sharks rely on the smallest of fish to satiate their appetites, and they’re often mistaken for whales because of this filter-feeding tendency. Basking sharks (also known as bone sharks) are second only to whale sharks in size, making them the second-largest fish in the ocean. They may look threatening, but basking sharks are actually some of the gentlest sharks in existence. Read on to find out more about these fascinating friends.

Species Information

Basking sharks are massive animals, and they range in size from 22 to 29 feet on average. Although this is the standard range, the largest recorded individual was measured at a whopping 40 feet long! The skin of a basking shark is a mottled, greyish brown. While other species may have a more vibrant or vivid color, these creatures keep it simple.

Along with being the second largest fish in the world, basking sharks can also weigh up to five tons, and they’re only dwarfed in size by the whale shark. It’s no wonder basking sharks are a slow-moving species that takes their time while navigating the seas. This partially explains why basking sharks are migratory in nature, since traveling to new locations requires much time and effort.

Even though basking sharks are virtually always on a journey, they like to savor their time along the way. Basking sharks got their name from their tendency to “bask” in the sunlight and sun themselves near the ocean’s surface. This species can filter up to 2000 tons of sea water per hour to capture enough zooplankton for a full meal.

This feeding practice requires using the large gill slits that encircle nearly the entire basking shark head, while hundreds of tiny teeth act as filters. Feeding is passively done while swimming so that the basking shark can capture thousands of tiny fish for their next meal.

Thanks to IUCN’s Red List, basking sharks were unfortunately categorized as endangered in 2018. While these peaceful predators can live to be an estimated 50 years old, it’s only through conservation efforts that this can continue to happen in the future.

Troublesome Travelers

Basking sharks are known for leaping high out of the water and occasionally putting on a show for humans. While this may feel magical for onlooking humans, there’s speculation that the basking shark actually makes these leaps in an attempt to remove sea parasites from their skin.

Even though sea lampreys start out as sediment feeders, they eventually make their way out into nature as adult parasites. Lampreys will often find a new host and latch on, draining the host of vital fluids and nutrients. Their benefit from feeding on large parasites like basking sharks is quite pronounced.

The first step of this process requires lampreys to penetrate past the hardened skin of basking sharks. Once they achieve this feat, they have to reckon with the high urea levels in both the blood and tissues of the basking shark. Filtering is not a problem for lampreys, as they’ll usually dispel the urea while feeding to avoid ingesting it. Using their anti-clotting saliva, they’re able to stop wounds from healing while they feed. This adaptation makes it easier to siphon more nutrients from their host without having to start over.

This process no doubt causes a skin reaction in basking sharks, and their effects run even deeper. Basking sharks rely on urea to regulate the pressure in their bodily fluids. Without a steady amount of urea, the basking shark body can be thrown far out of equilibrium. This can be even more serious if multiple parasites are present at once. It’s not currently proven that basking sharks breach the water to rid themselves of these parasites, but it would certainly be understandable if that is the reason!

Where Can You Find Basking Sharks?

Basking sharks are considered to be a coastal-pelagic species that dwell mainly in arctic & temperate waters worldwide, from depths of 200 to 2000 meters deep. They’re well known for entering bays & estuaries, as well as offshore areas on occasion. Basking sharks are most prevalent throughout the Atlantic and Pacific oceans, in the Mediterranean Sea and Sea of Japan, and off the coast of southern Australia and New Zealand.

Basking sharks are known for not traveling solo, and they’re frequently seen either in pairs or in schools of up to 100 individuals. Compared to other species, basking sharks are usually recognizable because they travel nose to fin with these other individuals. This practice forms a visible line throughout the water and makes them easy to spot.

Are Basking Sharks Dangerous or Friendly?

As far as ocean predators, basking sharks are one of the most passive shark species around humans. Since the teeth of basking sharks have adapted for filter feeding, they pose no immediate danger to humans from their bite. However, basking sharks are still large creatures and the denticles on their skin can cause abrasions by basic touch, so it’s best to avoid getting too close.

Generally, basking sharks are tolerant to both boats and divers, with the exception being after an attempted harpooning. This is considered to be a provoked attack, and it’s the exception to the rule. Unprovoked, these gentle creatures provide virtually no threat to human beings.

Can a Basking Shark Eat a Human?

Basking sharks are filter feeders, and they usually keep their mouth wide open while swimming in an attempt to catch tiny fish for their next meal. Despite having their massive, 1-meter-diameter jaw opened wide while traversing the ocean, basking sharks would have no way of eating a human. The teeth of a basking shark have evolved to aid in filtering instead of chewing, so there’s no inherent threat to humans. Even if a human attempted to be filtered into the mouth of a basking shark, there would be no way for digestion to occur.

This fact is further confirmed by the zero historical or modern-day reports of basking sharks eating humans. It’s speculated that much of monster folklore has originated from watching basking sharks swimming together in a line to form tales of mysterious creatures, but that’s about the only danger that they present. Basking sharks may appear to be intimidating, but they’re really benign creatures.

Why Are Basking Sharks Hunted?

Basking sharks have been sought out for their meat, oil, livers and fins in the past, but hunting is now outlawed in most areas except for China and Japan. The fins of the basking shark are popular for shark fin soup, the liver is seen as a health food or aphrodisiac, and the oil is used as an important ingredient in cosmetics.

In addition to being sought out intentionally, unintentional methods can still accidentally capture these monolithic creatures. Basking sharks can still easily be caught as a result while fishing for other ocean life. They are also vulnerable to overfishing because of their extremely slow growth during maturation, and they have an incredibly long gestation period in the womb.

Although it’s unclear exactly how long this gestation lasts, it’s speculated that basking sharks may spend up to three years total growing in the womb. This ultimately means less sharks being birthed to replace the population than other shark species, and it’s been one of the unique factors leading to their endangered status.

Seemingly because of their size, basking sharks have few natural predators in the wild. Most other sharks and large sea life leave them alone, but various species of white sharks have been said to scavenge and possibly consume their remains after death.

Along with whale sharks, basking sharks are mostly seen as the gentle giants of sea life. Despite zero unprovoked attacks on humans, they’ve been almost hunted to extinction over the last century. As a result of these methods, it’s difficult to say whether or not they’ll still be around in the future with such a slow growth rate. Conservation is an important part of preserving shark species, and basking sharks fall right in line with that mission!

Works Cited

Knickle, C., Billingsley, L. & DiVittorio, K. No date specified. Cetorhinus maximus. Florida Museum. Retrieved January 6, 2022, from https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/cetorhinus-maximus/.

No author specified. (November 7, 2018). Basking Shark. IUCN Red List. Retrieved January 6, 2022, from https://www.iucnredlist.org/species/4292/194720078.

No author or date specified. Can Basking Sharks Eat Humans? American Oceans. Retrieved January 6, 2022, from https://www.americanoceans.org/facts/can-basking-sharks-eat-humans/.

No author specified. (November 23, 2018). Basking shark. Government of Canada. Retrieved January 6, 2022, from https://www.dfo-mpo.gc.ca/species-especes/profiles-profils/baskingshark-requinpelerin-atl-eng.html.

No author or date specified. Basking shark. Oceana. Retrieved January 6, 2022, from https://oceana.org/marine-life/basking-shark/.

Casey, D. (February 14, 2019). Petromyzon marinus (revisited). Parasite of the Day. Retrieved January 10, 2022, from http://dailyparasite.blogspot.com/2019/02/petromyzon-marinus-revisited.html.