The Frilled Shark Undergoes a 3-Year Gestation Period Before Birth

The frilled shark (Chlamydoselachus anguineus), often referred to as the scaffold shark, is widely recognized as a "living fossil." This primordial shark has barely evolved over millions of years, providing a fascinating insight into prehistoric marine life. It remains the only extant member of its shark family.

Encountering this elusive shark species is a rarity, as they inhabit the ocean's depths, far from the surface. Although frilled sharks may live for around 25 years, their presence significantly influences their ecosystems throughout their lifespan.

Physical Characteristics

The frilled shark boasts an elongated, eel-like physique, reaching lengths of up to 6.5 feet (2 meters). Its dark brown or gray body is cylindrical, tapering into a flattened tail. The shark derives its name from the six pairs of frilly gill slits adorning its throat, which contribute to its unique, ancient appearance.

In contrast to most sharks, the frilled shark lacks a distinct dorsal fin near its tail. Its pectoral fins are modest in size and positioned closer to the head. However, it features a sizable anal fin and smaller pelvic fins on its underside, aiding in propulsion.

Its broad mouth is equipped with rows of sharp, needle-like teeth, ideal for capturing elusive prey.

2 Frilled Shark Species

Two recognized species of frilled sharks exist: the common frilled shark (Chlamydoselachus anguineus) and the Southern African frilled shark (Chlamydoselachus africana).

The common frilled shark inhabits various deep-sea regions across the globe, such as the Western Indian Ocean. In contrast, the Southern African frilled shark predominantly resides in the Atlantic Ocean.

While these species share a similar appearance, they exhibit slight variations in their habitats and physical traits. For example, the common frilled shark possesses shorter gill slits, whereas the Southern African variant features longer gills and a more compact head.

Both species are equally rare and difficult to observe, posing significant challenges for researchers.

Social Habits

Frilled sharks are solitary creatures, predominantly dwelling near the ocean floor. As ambush predators, they patiently wait for prey to approach. Due to the remote and isolated nature of their habitat, interactions with other sharks or marine species are seldom observed.

Unlike their surface-dwelling counterparts, frilled sharks do not gather in schools or exhibit social behaviors. Their existence in the deep ocean is marked by solitude and a focus on survival. Their exceptional hunting skills make solitary living a non-issue.

Diet

This eel-like shark is a carnivorous predator, primarily consuming squid, fish, and various deep-sea creatures.

Equipped with rows of razor-sharp, backward-facing teeth, they efficiently seize and secure slippery prey. Their flexible jaws allow them to swallow their catch whole. Their speed and ferocity eliminate the need for luring prey.

Their diet is a reflection of their deep-sea environment, where food is often scarce. Frilled sharks have evolved to capitalize on every hunting chance, occasionally pursuing prey larger than themselves. Life as a frilled shark is tough, but escaping one is even tougher!

Environment

Frilled sharks inhabit depths ranging from 1,500 to 5,000 feet (500 to 1,500 meters). To put this into perspective, the average ocean floor lies at approximately 12,000 feet (3,700 meters).

They thrive in cold, dark waters close to continental shelves and upper slopes, where they can stealthily hunt. This species has been discovered in oceans across the globe, including regions near Japan, Australia, and Namibia.

Residing at such extreme depths, frilled sharks seldom cross paths with humans, enhancing their enigmatic nature. Their deep-sea habitats shield them from most predators but also pose significant challenges for researchers attempting to study them.

Life Cycle

Frilled sharks boast an exceptionally lengthy gestation period, potentially lasting up to three and a half years — the longest among all vertebrates. This slow reproductive rate contributes to their rarity. Additionally, they have a specific breeding season rather than reproducing year-round.

Female frilled sharks deliver live offspring, usually between 6 and 12 pups per litter. The newborns are fully developed replicas of adults and must survive independently from the moment they are born.

Conservation Status

Frilled sharks are not presently listed as endangered, but their deep-sea environments make population estimates challenging.

They are sometimes unintentionally caught in deep-sea fishing operations, potentially threatening their population. Additionally, climate change and deep-sea mining could adversely affect their habitats in the future.