SHARK VS SHARK

CladoselachevsCommon thresher

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

ExtinctCladoselache fyleri×LivingAlopias vulpinus
QUICK VERDICT

Common thresher is about 4.2× longer by these reference values.

Common thresher uses a 7.6 m upper reference, compared with 1.8 m for Cladoselache. 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
ACladoselacheabout 1.8 m / 6 ft
BCommon thresherreported to 7.6 m / 24.9 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.

MeasureCladoselacheCommon thresher
Length referenceabout 1.8 m / 6 ftreported to 7.6 m / 24.9 ft
Weight referenceNot reliably reconstructedrecorded over 340 kg / 750 lb
Bite forceNo defensible estimate usedUnknownNo dependable maximum foundUnknown
Timeabout 370 million years agoTemperate and tropical open waters
DietSmall fishesSchooling fishes and squid
03

WHAT THE DATA CAN SAY

Size is not the whole animal.

Length and weight

Cladoselache is represented by about 1.8 m / 6 ft; Common thresher by reported to 7.6 m / 24.9 ft. Calling it a modern-style shark hides major evolutionary distance. Length comparisons can exaggerate body bulk because the tail is exceptionally long.

Bite evidence

Cladoselache: No usable maximum-force model exists. Common thresher: Its hunting performance cannot be reduced to jaw 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

It was an early shark-like chondrichthyan with a streamlined body. Much of its length is tail, which it uses to stun prey.

04

TRACE THE CLAIMS

Sources and limits.

CladoselacheSmithsonian National Museum of Natural HistoryCommon thresherFlorida MuseumHow we standardize comparisonsRead the methodology →