Swimming with the elusive oarfish

When early sailors told fantastical stories of sea serpents, what animals were they truly seeing? In this episode of River Monsters, host Jeremy Wade looks for the origin of these legends, first off the British coast, then in Thailand. But when he investigates the Nāga, a mythical serpent from eastern lore, he realizes that the elusive oarfish may be the real-life giant ‘sea serpent’ from these seafaring tales.

In this Discovery UK clip, Wade searches for one off the coast of France. Though the first dive is mentally and physically challenging, his second dive yields an exciting encounter.

Related reading: Why Touching Marine Life is Never Okay.

The mysterious oarfish is not a dangerous sea monster. Though they are large—some reports have measured them as long as 11 meters to 17 meters (36 feet to 56 feet)—in the few encounters humans have had with this fish, they are quite docile. A description from The Los Angeles Times:

Despite its great size, the fish orients itself vertically, with its head toward the ocean surface, and its blunt tail hanging down. This allows the fish to scan the water above for the krill and other small crustaceans that it eats, and may help it appear smaller to predators who are lurking below, said [marine biologist Mark] Benfield.

“The striking thing is they swim by undulating their dorsal fin like a propeller, and they can change direction instantly,” Benfield said. “Most of the time they move slowly and stealthily, but when they want to, they can move fast.”

Explore other videos of lesser-seen creatures, including:
• The pointy-nosed blue ratfish Hydrolagus trolli
• The elusive Black Seadevil Anglerfish
• Red Batfish or Starry Handfish
• Leptocephalus, a transparent eel larva in the wild