SHARK VS SHARK

Bluntnose sixgillvsSqualicorax

Length, weight and bite evidence—plus context from a human, city bus and blue whale. Every number below carries its uncertainty with it.

LivingHexanchus griseus×ExtinctSqualicorax pristodontus
QUICK VERDICT

Squalicorax is about 1.04× longer by these reference values.

These animals are effectively close in maximum-length terms, so measurement uncertainty can matter more than the apparent difference. A clean mass ratio is not shown because at least one weight is not reliably reconstructed.

01

ON THE SAME SCALE

Human. Bus. Whale.
Pick your reference.

RELATIVE LENGTH · 0–24 METERS
ABluntnose sixgillreported to 4.8 m / 15.8 ft
BSqualicoraxestimated to about 5 m / 16 ft
REFAdult human1.8 m · about 80 kg

Length bars use upper comparison values and do not show body depth, tail proportion or typical adult size. A long thresher tail, for example, does not equal whale-shark body mass.

02

THE NUMBERS

Side by side.

MeasureBluntnose sixgillSqualicorax
Length referencereported to 4.8 m / 15.8 ftestimated to about 5 m / 16 ft
Weight referencepublished to 590 kg / 1,300 lbNot reliably reconstructed
Bite forceNo dependable maximum foundUnknownNo defensible estimate usedUnknown
TimeDeep temperate and tropical watersabout 85–66 million years ago
DietFishes, rays, seals and carrionFishes, marine reptiles and carrion
03

WHAT THE DATA CAN SAY

Size is not the whole animal.

Length and weight

Bluntnose sixgill is represented by reported to 4.8 m / 15.8 ft; Squalicorax by estimated to about 5 m / 16 ft. Deepwater sampling is difficult, so upper records are sparse. Body length and ecology are reconstructed from incomplete fossil evidence.

Bite evidence

Bluntnose sixgill: No standardized maximum is available. Squalicorax: Bite traces show feeding, not maximum force.

Living versus extinct

At least one animal is known from fossils. Fossil length, weight and bite estimates depend on which living analogues and scaling equations researchers choose.

Ecology changes the matchup

Its six gill slits mark an ancient branch of shark diversity. Serrated teeth and bite traces show a broad, opportunistic diet.

04

TRACE THE CLAIMS

Sources and limits.

Bluntnose sixgillFlorida MuseumSqualicoraxPaleobiology DatabaseHow we standardize comparisonsRead the methodology →