Fun facts about Basking Sharks

After taking a closer look at the gentle whale shark, here is another gentle shark species: the basking shark. These enormous, filter-feeding sharks inspire awe and curiosity among marine enthusiasts. While not as popular as the whale shark, this is also a less studied species that still holds some mystery for scientists.

The Enigmatic Basking Shark

Basking sharks are the second-largest living shark species, after the gigantic whale shark. They can reach lengths of up to 12 meters or more, making them an imposing presence in the open ocean. Despite their formidable size, they are filter feeders like whale sharks.

These sharks possess an elongated body with a massive, gaping mouth that can extend up to one meter wide.

Despite their enormous size, basking sharks have relatively small teeth, which are not used for biting or tearing, as they have an elaborate filtering system that allows them to retain plankton and other small organisms while they filter water.

Their skin is thick and rough, often covered in parasite scars, and it can be gray or brown in coloration. Basking sharks also have a unique dorsal fin that is large and triangular, making it easy to spot when they swim close to the surface.

The incredible mouth of a basking shark (photo Greg Skomal)

Feeding Habits

One of the most remarkable aspects of basking sharks is their feeding strategy. Unlike some of their more aggressive shark cousins, basking sharks are filter feeders. They primarily feed on plankton and other tiny organisms that drift through the water such as larvae and small shrimps. They have a set of gill rakers that act like a sieve, allowing them to filter out plankton while expelling excess water through their gills.

Basking sharks are often seen near the surface of the water with their enormous mouths wide open. This behaviour is known as "basking," which is believed to help them maximize their filter-feeding efficiency. As they slowly swim forward, water flows over their gill rakers, trapping plankton and other small prey in the process.

Given its size, the basking shark needs to eat several hundreds of kilos of plankton and small organisms every day. They filter huge amounts of water every hour through their gills in order to get enough food!

Basking shark at the surface (photo Ross Beane)

Reproduction

The reproductive biology of basking sharks is a topic of ongoing research and a lot of their reproduction cycle is still unknown to scientists. Their mating behavior or birthing grounds are still quite mysterious.

These sharks are known to have a slow reproductive rate, which makes them vulnerable to population declines. Basking sharks are ovoviviparous, meaning that they give birth to live pups, but the embryos develop inside egg capsules within the mother's body. Pregnant female basking sharks can carry multiple embryos, and the gestation period is estimated to last between 9 to 12 months. Once the embryos are developed, they are born as fully-formed pups measuring about 1.5 meters in length, so quite some big baby sharks from the beginning!

Where to See Basking Sharks

If you're eager to catch a glimpse of these gentle giants in their natural habitat, there are several locations around the world where basking sharks are often spotted. Here are a few notable places:

1. Scotland's Hebrides: The waters around the Hebrides, off the west coast of Scotland, are a hotspot for basking shark sightings. The area's nutrient-rich waters attract large populations of plankton, making it an ideal feeding ground for these sharks. Spring and summer are the best times to spot them here.

2. Ireland: Ireland's coasts, especially around the counties of Cork and Kerry, are known for basking shark sightings. The Atlantic Ocean's currents bring plankton close to shore during the summer months, making it a prime time to spot basking sharks. While basking sharks are not among the deadly wild animals in Ireland, their impressive size can still make encounters thrilling for observers.

3. Canada's Atlantic Provinces: The Canadian provinces of Nova Scotia and New Brunswick offer opportunities to see basking sharks during their summer migrations. The Bay of Fundy, known for its extreme tides, is one of the places where these sharks can be spotted.

4. New Zealand: The waters around New Zealand's South Island are home to a significant basking shark population. If you're in the southern hemisphere, this is an excellent place to observe them.

When planning a trip to see basking sharks, it's essential to consider the best time of year for a better chance at sightings, which is typically during their feeding season in late spring and summer. As basking sharks come close to the surface to feed, some of these places offer trips where you can observe them from the boat. In some areas you can also snorkel or dive with these beautiful animals.

Basking shark feeding (photo Shark Guardian)

Conservation status

Despite their gentle nature, basking sharks face several threats, primarily due to human activities. Bycatch is one of the most common issues they are facing, as well as boat strikes. General degradation of the marine environment is also a threat as they feed exclusively on plankton and similar small organisms. If these decline then basking sharks have a harder time feeding.

To witness these gentle sharks in their natural habitat is a privilege that many marine enthusiasts seek. Whether you plan to visit the coast of Scotland, Ireland, New Zealand, or other popular locations to see them, knowing when and where to see basking sharks can enhance your chances of experiencing this remarkable marine creature.

Are you a shark enthusiast? Excellent choice! If you would like to read more, check out our posts about hammerhead sharks, tiger sharks or silky sharks to learn more about other shark species.