Basking shark

About the Basking shark

If the twilight zone had a yearbook, the basking shark would definitely be named “Most Chill.” Well, unless the yearbook committee included copepods or juvenile fish. The basking shark inhales huge amounts of these hapless creatures for breakfast-- but it’s not personal, they’re just eating with their mouths open.

Though the “Biggest Fish in the Ocean” title goes to the whale shark, the basking shark would probably still make the basketball team. It averages 8 meters (26 feet) but some individuals have been recorded as large as 12 meters (40 feet). Sadly, the species is endangered due to overfishing and an eradication program in the northeast Pacific.

The basking shark gets its relaxed reputation from the way it seems to “bask” in warm surface waters, in almost every ocean around the world. Studies have shown that they follow swarms of zooplankton that pop up along continental shelf “fronts” during phytoplankton blooms. The basking shark’s filter-feeding style is similar to that of the whale shark and megamouth shark, but these guys don't bother pumping water into their mouths like their fellow planktivores. Their approach is called “ram feeding” but in reality it’s pretty passive: a basking shark will swim slowly through dense patches of zooplankton, filtering out the water through gill rakers encircling its head.

Basking sharks are known to dive to depths of 900 meters (3,000 feet) in the ocean’s twilight zone, presumably in search of a zooplankton dinner. Recent studies have shown they’ll spend up to four months in the mesopelagic zone, but they’re not hibernating. Kind of like snow birds, they travel thousands of miles in search of exotic snacks, chill vibes, and maybe even a kindred spirit to settle down with. After all, there is life after high school.

Quick Facts

Common NameBasking shark
Scientific NameCetorhinus maximus
Other NamesBone shark, elephant shark, hoe-mother or homer (meaning “mother of pickled dogfish” in Orkney dialect)
Size7-8.5 meters (23-28 feet)
DiscoveryJohan Ernst Gunnerus, 1765
Eats what?Zooplankton, very small fish
Eats how?This “ram feeder” swims through dense patches of zooplankton with its mouth open, passively filtering food through its gill rakers.
Is eaten by?Orcas, humans
BioluminescenceYes, on the sides