The Goblin Shark's Unique Defense Mechanism: Its Oil-Rich Liver

Much about the goblin shark (Mitsukurina owstoni) remains a mystery to scientists, as these elusive creatures inhabit depths that are largely inaccessible to humans.

Inhabiting the benthopelagic zone, goblin sharks are typically found at depths of 800 to 3,000 feet (244 to 914 meters). Since their initial discovery in 1898, only about 50 specimens have been documented, primarily near Japan, Portugal, the Gulf of Mexico, and the California coastline.

What Do Goblin Sharks Look Like?

With its protruding jaws, small eyes, and unusually flat snout, the goblin shark has a face that could be likened to a surreal Picasso artwork. Its extended nose, combined with its extendable jaw, forms a unique facial structure rarely seen, even in the depths of the ocean.

The goblin shark's mouth contains three rows of approximately 25 jagged, needle-like teeth on both the upper and lower gums. Its jaw placement is unusual due to a dual set of ligaments, allowing it to extend and retract its jaws when feeding.

The goblin shark's soft, flabby body is covered in translucent, pinkish skin, colored by the visible blood vessels beneath. Typically measuring around 12 feet (3.6 meters) in length, these sharks are substantial in size, weighing approximately 400 pounds (181 kilograms).

The goblin shark's eerie appearance has earned it names like 'goblin shark' or 'elfin shark,' but its peculiar features are actually evolutionary traits. (This also applies to its wide-mouthed relatives, the mackerel sharks.) For example, its flattened snout contains ampullae of Lorenzini, which act as electrical sensors to locate prey.

Sharks possess a unique ability known as electroreception. The ampullae detect faint electrical signals emitted by living fish and animals during muscle movements. This natural tracking system enables goblin sharks to locate prey. Once a target is found, their retractable jaws swiftly capture the meal.

Despite its considerable size, the goblin shark can stealthily approach prey, thanks to an unexpected feature: its liver.

The goblin shark's oily liver is proportionally large, making its body nearly as dense as water. This buoyancy allows it to move effortlessly and approach prey with minimal effort, making it an efficient hunter.

Why Are Goblin Sharks Considered Living Fossils?

Goblin sharks are often referred to as living fossils, as they were once believed to be extinct. Although they have only been documented in modern science for about a century, the species is thought to have existed for approximately 125 million years.

The discovery of the goblin shark near Japan in 1898 sparked a sense of scientific déjà vu. Researchers recognized the species not from living specimens but from ancient fossil records.

Fossils of the Scapanorhynchus species, over 100 million years old, closely resemble the goblin shark. The likelihood of this similarity being coincidental is minimal, given the shark's unique and unmistakable physical characteristics.

Goblin sharks are estimated to live up to 60 years, though precise data is scarce due to their elusive nature. Comparisons between modern specimens and ancient fossils indicate that these bony fish have remained largely unchanged over millions of years.

What Do Goblin Sharks Eat?

Studies on the few goblin sharks captured suggest their primary food sources consist of fish, shrimp, and squid.

Gathering detailed dietary information is difficult, as most captured specimens have empty stomachs. For instance, a large-scale study in 2006 found that 29 percent of the 148 goblin sharks examined had no stomach contents.

The most recent goblin shark sighting occurred near Taiwan in 2023, involving a pregnant female with six pups. Earlier, in 2007, one caught in Tokyo Bay, Japan, survived only a day in captivity.

Given the rarity of encounters, it could take many years before we fully unravel the secrets of the goblin shark.

4 Other Living Fossil Fish

These aquatic creatures are regarded as living fossils, either because they have remained largely unchanged for millions of years or because they were once thought to be extinct before being rediscovered.

1. Sturgeon

The sturgeon is the largest freshwater fish, capable of living over 100 years. Like the goblin shark, it possesses a retractable jaw. This species is believed to date back to the Middle Jurassic period, approximately 174 to 16 million years ago.

2. Lamprey

Often called a "vampire fish" or the "ancient vampire of the ocean," this jawless, parasitic creature feeds by draining the bodily fluids of its prey. Studies indicate that it has remained virtually unchanged for over 340 million years.

3. Frilled sharks

Known as "lizard sharks," these creatures have an eel-like body with snake-like heads and are thought to have existed for around 80 million years.

4. Alligator Gar

Among the largest freshwater fish in North America, these creatures are toxic to humans due to their poisonous eggs. Fossil evidence suggests they have existed for approximately 100 million years.