Why Is It Called Sperm whale?

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

The sperm whale (Physeter macrocephalus) is named after spermaceti, a milky-white, waxy substance found in its massive head. When 18th-century whalers discovered this unusual organ, they assumed the white substance was the whale’s sperm, naming it “spermaceti” (from Latin sperma ceti, meaning “whale seed”). In reality, spermaceti has nothing to do with reproduction—it functions in echolocation and buoyancy control.

The Origin of the Name

How the Misunderstanding Happened

Factor	Observation	Conclusion (Wrong)
Color	Milky white	Looked like semen
Consistency	Liquid when warm	Seemed biological
Location	Inside head	Unknown organ function
Quantity	Up to 500 gallons	Must be important
Temperature	Body temperature	Seemed “alive”

18th-century whalers lacked knowledge of marine mammal anatomy. When they opened a sperm whale’s head and found gallons of mysterious white fluid, their assumption—while incorrect—was logical given the available evidence.

Timeline of Naming

Year	Event	Significance
~1600s	First spermaceti harvests	Whalers name the substance
1712	Nantucket sperm whaling begins	Commercial hunting expands
1758	Linnaeus classifies species	Scientific name: Physeter macrocephalus
1800s	Peak of sperm whaling	Name firmly established
1970s	True function understood	Too late to change common name

Alternative Names Used Globally

Region	Name	Meaning	Why Used
France/Spain	Cachalot	”Big head”	Describes anatomy
Germany	Pottwal	”Pot whale”	Head shape
Japan	Makkou kujira	”Incense whale”	Ambergris connection
China	sperm whale (Mǒxiāngjīng)	“Ambergris whale”	Valuable product
Norway	Spermhval	Direct translation	English influence
Scientific	Physeter macrocephalus	”Big-headed blower”	Accurate description

What Spermaceti Actually Is

Chemical Composition

Component	Percentage	Property
Wax esters	76-88%	Main component
Triglycerides	10-20%	Fat molecules
Free fatty acids	1-5%	Minor component
Sterols	<1%	Trace amounts

Physical Properties Comparison

Property	Spermaceti	Actual Whale Sperm	Obvious Difference
Volume per whale	500 gallons	Milliliters	Massive difference
Location	Head organ	Reproductive tract	Different anatomy
Function	Echolocation, buoyancy	Reproduction	Unrelated
Consistency	Waxy solid	Biological fluid	Distinct texture
Melting point	35-40°C	N/A	Unique property

Real Functions of Spermaceti

Modern research has identified the actual purposes of spermaceti:

Primary Function: Echolocation

Aspect	Description	Evidence
Sound focusing	Acts as acoustic lens	CT scan studies
Click production	Generates echolocation clicks	Bioacoustic research
Range	Enables detection 1+ miles away	Field observations
Prey location	Finds squid in total darkness	Foraging success data

Secondary Function: Buoyancy Control

Depth	Spermaceti State	Effect
Surface	Liquid (warm)	Lower density, easier floating
Diving	Cooling/crystallizing	Higher density, easier descent
Deep hunting	Solid (cold)	Neutral buoyancy maintained
Ascending	Rewarming/melting	Lower density, assists rise

Research in Marine Mammal Science shows that sperm whales can regulate blood flow to their spermaceti organ, controlling its temperature and thus its density during dives to 3,000+ meters.

Why the Inaccurate Name Persists

Reasons Common Names Rarely Change

Factor	Explanation
Historical usage	Centuries of established literature
Recognition	Public knows “sperm whale”
Scientific precedent	Formal classifications reference it
Translation chains	Name embedded in multiple languages
Practical confusion	New names create more problems

Despite understanding that the name is anatomically incorrect, changing “sperm whale” would require updating countless books, databases, and legal documents—a practically impossible task.

Frequently Asked Questions

Is it inappropriate to call it a sperm whale?

No, “sperm whale” is the official common name recognized by NOAA, the International Whaling Commission, and major scientific organizations. While the etymology involves a historical misunderstanding, the name itself is simply a proper noun—like “Greenland” (which isn’t green) or “Guinea pig” (which isn’t from Guinea). Context makes the meaning clear.

What would be a more accurate name?

The scientific name Physeter macrocephalus means “big-headed blower,” which accurately describes the whale’s distinctive anatomy. Alternative names like “cachalot” (from Portuguese, meaning “big head”) focus on the whale’s appearance rather than the misidentified substance. However, “sperm whale” remains the standard English common name.

Why did whalers care so much about spermaceti?

Spermaceti was extremely valuable because it produced the finest candles available before electric lighting. Spermaceti candles burned brighter, longer, and cleaner than any other wax, with no unpleasant smell. The substance was also an excellent lubricant for fine machinery and watches. A single large whale’s spermaceti could be worth thousands of dollars in today’s currency.

How much spermaceti does a sperm whale have?

Adult male sperm whales can have up to 500 gallons (1,900 liters) of spermaceti in their heads—enough to fill a small hot tub. Females have proportionally less. This enormous quantity made sperm whales the most commercially valuable whaling targets, contributing to severe population declines.

Is spermaceti still used in products?

No, genuine spermaceti has been banned since sperm whales received international protection in 1986. Modern products that once contained spermaceti now use synthetic alternatives like jojoba oil or laboratory-created wax esters. These substitutes actually perform better than natural spermaceti in most applications.

The Spermaceti Organ

Anatomical Details

Feature	Measurement	Comparison
Length	12-18 ft (4-5.5m)	Length of a van
Weight	4-6 tons	Weight of an elephant
Capacity	500 gallons (1,900 L)	Large hot tub
Position	Front of head	Largest single organ

Head Structure Breakdown

Component	Function	Size
Spermaceti organ	Echolocation/buoyancy	25-30% of head
Junk (connective tissue)	Sound focusing	20-25% of head
Melon	Acoustic lens	10-15% of head
Right nasal passage	Click production	15% of head
Skull and brain	Standard functions	20% of head

Impact on Whale Populations

The value of spermaceti drove intensive hunting that severely impacted sperm whale populations:

Era	Estimated Population	Annual Kill Rate
Pre-1712	1.1 million	0 (commercial)
1800-1850	900,000	5,000/year
1850-1900	600,000	8,000/year
1900-1950	400,000	10,000/year
1950-1986	300,000	20,000/year peak
Current	~300,000	0 (protected)

The sperm whale’s unfortunate name reflects the very industry that nearly hunted them to extinction for the substance their heads contained.

For more on sperm whale biology, explore why they’re called sperm whales, sperm whale size, and whether whales are mammals.

Related Questions

• Why are They Called Sperm Whales?
• How Big is a Sperm Whale?
• What Do Sperm Whales Eat?
• Is a Whale Mammal?