Why Are They Called Sperm Whales?

Quick Facts

Attribute	Details
Type	Marine mammal
Family	Cetacea
Habitat	Oceans worldwide
Conservation	Protected in most countries
Research Status	Ongoing scientific study

The Short Answer

Sperm whales (Physeter macrocephalus) get their name from spermaceti, a waxy, oil-like substance found in their enormous heads. When 18th-century whalers first discovered this milky-white substance, they mistakenly believed it was the whale’s reproductive fluid, naming it “spermaceti” from the Latin sperma ceti meaning “whale sperm.” The substance is actually completely unrelated to reproduction—it helps with echolocation and buoyancy control.

The Etymology of “Sperm Whale”

Historical Development of the Name

Period	Term	Origin	Usage
Ancient	Physeter	Greek (φυσητήρ)	“Blower” - referring to spout
1600s	Spermaceti whale	English whalers	Named after head substance
1700s	Sperm whale	Shortened English	Common name emerges
1758	Physeter macrocephalus	Linnaeus	Scientific classification
Present	Sperm whale / Cachalot	International	Both names used

The scientific name Physeter macrocephalus means “big-headed blower”—a more anatomically accurate description than the common name.

Names in Other Languages

Language	Name	Literal Meaning
French	Cachalot	From Portuguese “cachola” (head)
Spanish	Cachalote	Same Portuguese origin
German	Pottwal	Pot whale (head shape)
Japanese	Makkou kujira (マッコウクジラ)	Incense whale (ambergris)
Russian	Kashalot (Кашалот)	From French cachalot
Chinese	Mǒxiāngjīng (sperm whale)	Ambergris whale
Portuguese	Cachalote	Big head

Many languages use names referring to the whale’s distinctive head shape or valuable products (ambergris) rather than the spermaceti organ.

What Is Spermaceti?

Physical Properties

Property	Description	Details
Appearance	Milky white, waxy	Crystallizes when cooled
Consistency	Liquid when warm	Solidifies at room temperature
Location	Spermaceti organ (head)	1,900 liters in adult male
Composition	Wax esters, triglycerides	Unique chemical structure
Melting point	35-40°C (95-104°F)	Close to body temperature

Why Whalers Valued Spermaceti

Use	Application	Value
Candles	Premium, smokeless light	Most expensive candle wax
Lubricants	Fine machinery, watches	Superior to other oils
Cosmetics	Creams, ointments	Remained stable, non-rancid
Pharmaceuticals	Medicinal preparations	Believed to have healing properties
Textiles	Leather treatment	Waterproofing

A single large sperm whale could yield up to 500 gallons (1,900 liters) of spermaceti, making them the most valuable whaling targets. This drove intensive hunting that reduced populations by an estimated 67% before protections were enacted.

Spermaceti Yield by Whale Size

Whale Size	Spermaceti Volume	Approximate Value (1850s)
Small male (35 ft)	100 gallons	$200
Medium male (50 ft)	300 gallons	$600
Large male (60 ft)	500+ gallons	$1,000+
Female (35 ft)	50-100 gallons	$100-200

The Real Function of Spermaceti

Modern science has revealed that spermaceti has nothing to do with reproduction. Its actual functions include:

Buoyancy Control Theory

Mechanism	Description	Evidence
Temperature regulation	Whale controls blood flow to organ	Observed changes during diving
Density changes	Cooling crystallizes wax, increasing density	Laboratory experiments
Neutral buoyancy	Helps whale maintain depth without effort	Dive profile analysis
Ascent control	Warming melts wax, decreasing density	Thermal imaging studies

Echolocation Enhancement Theory

Function	Mechanism	Support
Sound focusing	Spermaceti acts as acoustic lens	Anatomical studies
Click production	Focused through “junk” and “melon”	Bioacoustic research
Directional hearing	Shapes sound beam for prey detection	Behavioral observation
Long-range communication	Amplifies clicks for 10+ mile range	Acoustic recordings

Research published in the Journal of Experimental Biology suggests the spermaceti organ works as a sophisticated biological sonar system, enabling sperm whales to locate squid in the pitch-black depths where they hunt.

The Sperm Whale’s Remarkable Anatomy

Head Composition

Structure	Percentage of Head	Function
Spermaceti organ	25-30%	Contains liquid spermaceti
Junk	20-25%	Acoustic lens (connective tissue)
Melon	10-15%	Sound focusing
Right nasal passage	15%	Sound production
Left nasal passage	5%	Breathing only
Skull and brain	20%	Standard structures

The sperm whale’s head comprises up to one-third of its total body length—the largest head relative to body size of any animal.

Size Comparison

Measurement	Sperm Whale	For Comparison
Head length	16-20 ft (5-6m)	Length of a car
Head weight	16,000 lbs (7,300 kg)	Weight of 2 cars
Brain size	17 lbs (7.8 kg)	Largest brain on Earth
Spermaceti volume	500 gallons (1,900 L)	Hot tub capacity

Frequently Asked Questions

Is spermaceti actually related to sperm?

No, spermaceti has absolutely nothing to do with reproduction. The waxy substance is produced in the spermaceti organ in the whale’s head and functions in echolocation and possibly buoyancy control. 18th-century whalers simply assumed the white, milky appearance meant it was reproductive fluid—an understandable but incorrect assumption given the scientific knowledge of the time.

Why didn’t scientists change the name?

By the time scientists understood spermaceti’s true function, “sperm whale” was deeply established in English and scientific literature. Changing common names of well-known species is difficult and often creates more confusion than it solves. The scientific name Physeter macrocephalus (“big-headed blower”) is more anatomically appropriate, and alternative names like “cachalot” exist in other languages.

What was spermaceti used for?

Spermaceti was primarily used to make high-quality candles that burned brighter and cleaner than any other wax available. It was also used as a premium lubricant for fine machinery, in cosmetics and pharmaceuticals, and for treating leather. The candles were so valued that “spermaceti candle” became a unit of light measurement (candela) before electric lighting.

How is spermaceti different from whale oil?

Spermaceti is a waxy substance from the whale’s head, while whale oil (or “train oil”) comes from the whale’s blubber. Spermaceti was more valuable because it burned cleaner, remained solid at room temperature, and didn’t develop the rancid smell of blubber oil. A sperm whale yielded both products—spermaceti from the head and blubber oil from the body.

Do any products still contain spermaceti?

No, genuine spermaceti has been banned from commercial use since the 1970s when sperm whales received international protection. Synthetic alternatives called “jojoba oil” and “synthetic spermaceti” now replace it in cosmetics and industrial applications. These alternatives actually perform better than real spermaceti in most applications.

Other Valuable Sperm Whale Products

Ambergris: “Floating Gold”

Property	Details
Origin	Digestite waste product, possibly from squid beaks
Appearance	Gray, waxy, foul-smelling when fresh
Value	$10,000-$50,000+ per kilogram
Use	Perfume fixative
Legality	300,000-450,000 worldwide by country

Ambergris, another sperm whale product, remains legally tradeable in some countries because it’s found floating or beached rather than harvested from whales.

Conservation Status

Understanding why sperm whales were hunted helps explain their current conservation status:

Factor	Historical	Current
Population	1.1 million (pre-whaling)	~300,000
Decline	67% reduction	Slowly recovering
Primary threat	Spermaceti hunting	Ship strikes, fishing gear
Protection	None until 1982	International moratorium
IUCN Status	—	Vulnerable

For more on sperm whales, see how big sperm whales are, why they’re called sperm whales, and sperm whale diving abilities.

Related Questions

• Why is It Called Sperm Whale?
• How Big is a Sperm Whale?
• What Do Sperm Whales Eat?
• How Deep Can Sperm Whales Dive?