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8:56in productionCh. 1 · Living fossil/ 8:56 · ceiling 15 min
Fish & sea life

Frilled shark

A deep-dwelling eel-shark that ambushes like a coiled spring—and gestates longer than most mammals.

Frilled shark (Chlamydoselachus anguineus) is a deep-dwelling, eel-shaped shark with six fringed gill slits. It lives on outer continental shelves and upper slopes across the Atlantic and Pacific. It feeds on cephalopods, small sharks, and bony fish using diel vertical migration and specialised jaw mechanics. It reproduces aplacentally with gestation up to 3.5 years. IUCN lists it as Least Concern.

Chapters & takeaways4
  1. 0:59
    Living fossil

    It is one of only two surviving members of a shark family unchanged for tens of millions of years.

  2. 2:34
    Deep shelf, night surface

    It lives on the edge of the continental shelf, rising nightly to hunt where cephalopods gather.

  3. 4:04
    Rock-anchored lunge

    It anchors its tail, bends like an eel, and lunges—swallowing prey whole with 300 backward-pointing teeth.

  4. 5:18
    Three-and-a-half-year pregnancy

    It carries pups for up to 3.5 years without a placenta—longer than any other known shark.

Worth your time?

Yes. See the whole thing.

3.5/ 5
What works
  • jaw mechanics for swallowing whole prey
  • vertical migration aligned with cephalopod behaviour
  • morphology suited to rocky-bottom ambush in low light
What does not
  • breed seasonally
  • live in shallow water
  • have a placenta
  • feed during daytime at depth
See it if
  • marine biologists studying aplacental viviparity
  • researchers of ancient chondrichthyan morphology
  • scientists tracking deep-sea vertical migrants
Skip it if
  • divers
  • snorkellers
  • coastal educators
The written brief1 min read

What the species is and where it came from

Chlamydoselachus anguineus is one of two extant frilled sharks. It is a living fossil—primitive, eel-like, with six fringed gill slits—and belongs to the family Chlamydoselachidae. It shares its range and biology with C. africana.

How it works, in terms someone would actually use

It hunts at night near the surface, then retreats to the outer continental shelf and upper slope. It curls its tail against rocks, bends like an eel, lunges, and swallows prey whole with jaws full of 300 needle-like teeth.

What it gets right

Its jaw mechanics work for swallowing large, soft-bodied prey whole. Its vertical migration matches cephalopod behaviour. Its morphology suits slow, rocky-bottom ambush in low-light, high-pressure zones.

What it does not

It does not have a placenta. It does not breed seasonally. It does not live in shallow water, coral reefs, or midwater pelagic zones. It does not feed during the day at depth.

What it changed

Nothing in the material says it changed anything. No claim describes influence, impact, or alteration of ecosystems, science, or human practice.

Who it is for, and who it is not

It is for marine biologists studying aplacental viviparity, deep-sea vertical migrants, or ancient chondrichthyan morphology. It is not for divers, snorkellers, or coastal educators: it lives too deep, appears too rarely, and behaves too cryptically.

Is it worth your time

Yes—if you are tracking deep-sea predators that move like living fossils. No—if you expect frequent sightings, behavioural variety, or surface-level drama.

Same habitat · Fish & sea life4 of 43
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