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"Mother and baby sperm whale" This beautiful photo was taken by Inf-Lite Teacher.

Types of Sperm Whales

There are three Extant (living) species of sperm whales. They are divided into two closely-related families, the Physeteridae family; sperm whales, and the lesser known Kogiidae family ; miniature sperm whales (think miniature horses).

The Great Sperm Whale
The Physeteridae family has one living species; Physeter macrocephalus, the Great Sperm Whale. This is the sperm whale one normally thinks of... think Moby Dick. It is the largest odontocete (toothed whale), and one of the most widely known species of whale.

Miniature Sperm Whales
The Kogiidae family has two living species, Kogiabreviceps (the Pygmy Sperm Whale), and Kogia sime (the Dwarf Sperm Whale).

The Pygmy and the Dwarf Sperm Whales look very similar, in fact, for a long time they were considered the same species. They are similar to their big brother, the Great Sperm Whale in that have the typical very narrow lower jaw, and prefer to dive deep to feed on squid. Besides that, they look more like a porpoise than a whale. Their skulls are short and stubby looking, not like a Great Sperm Whale. Also, as the names suggest, their body length is much shorter, around 2 - 3 meters (7 - 10 feet); they look more like large porpoises than whales. One defining characteristic between Dwarf and Pygmy Sperm whales is Dwarf Sperm Whales have a taller dorsal fin.

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Ancient Sperm Whales

Although today there are only 2 genera and 3 species of sperm whale, in the past, the diversity was much greater.
In the Miocene, there were around 14 genera of sperm whale! Some were in the sperm whale family, and others were in the miniature family. They all had slight differences, from different skull and snout shapes, to different numbers and shapes of teeth. The diversity dropped at the end of the Miocene and Pliocene, until we have the 2 genera today. Luckily, today fossil hunters can find remains of these genera that Earth forgot.

The taxonomy of fossil sperm whales is unclear, mainly because many type specimens are undiagnostic. Basically, more fossil specimens need found and studied. Some of the genera that most authors agree upon include:

Physeteridae family: Ferecetotherium, Helvicetus, Idiorophus, Idiophyseter, Orycterocetus, Physeter, Physeterula, and Placoziphius
Kogiidae family: Aprixokogia, Kogia, Pusilla, Praekogia, and Scaphokogia

Livyatan melvillei
A giant sperm whale, Livyatan melvillei, was found in Peru in 2008. This Mega-Sperm Whale from the Miocene had a huge skull and large teeth in both the upper and lower jaw. It readed an estimated sizes of around 55 feet! This prehistoric monster could have eaten a Megalodon shark!

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Sperm Whales: The Details

Teeth
Sperm whales have between 20-26 teeth in each narrow lower jaw that do not erupt from the gums until puberty (5). Sperm whales usualy have NO teeth in the upper jaws, as they normally don't erupt from the gum line at all (5). Sperm whales appear to swallow their prey whole, so the teeth are not necessary for feeding. In fact some healthy sperm whales that have been caught have no teeth at all (5). The teeth they do have though are long and conical shaped and have been found to be up to 11 inches long.

Body Shape
In addition, sperm whales have a unique cavity in their head called a Spermaceti organ, so large that a small car would fit inside. This organ consists of two oil sacs that can hold up to 4 tons of a waxy substance called spermaceti oil. These whales can regulate the temperature of the spermaceti oil. When the oil drops below 31 degrees Celsius, it begins to crystallize into a solid (2). During a dive, the whale cools the oil into a solid that makes the whale less buoyant (2). When the whale is about to ascend, blood flow increases around the organ, warming it up (2). This changes the spermaceti crystals into a liquid and it causes the whale to become more buoyant and ascend (2). This is all done with very little energy expenditure.

Spermaceti Organ
In addition, sperm whales have a unique cavity in their head called a Spermaceti organ, so large that a small car would fit inside. This organ consists of two oil sacs that can hold up to 4 tons of a waxy substance called spermaceti oil. These whales can regulate the temperature of the spermaceti oil. When the oil drops below 31 degrees Celsius, it begins to crystallize into a solid (2). During a dive, the whale cools the oil into a solid that makes the whale less buoyant (2). When the whale is about to ascend, blood flow increases around the organ, warming it up (2). This changes the spermaceti crystals into a liquid and it causes the whale to become more buoyant and ascend (2). This is all done with very little energy expenditure.

Diving Ability
This feature makes sperm whales great divers. Most whales dive at depths above 1 km, but sperm whales far surpass this depth. The deepest recorded dive of a sperm whale is 2.25 km (3). In one instance, however, stomach contents from one whale contained a species of dog fish which live below 3 km (3). Not only are they the deepest diving whales, they are also the longest diving whales. The longest recorded dive by a whale (Guinness Book of Records) was that of a Sperm Whale. On 25th August 1969 a bull Sperm Whale surfaced from a dive lasting 1 hour 52 minutes. Those of you who are divers may be wondering how these whales avoid getting the bends. Well, they do get the bends! They just have unique ways to cope with it. For those of you who are not divers, the bends is a harmful and painful condition that can occur when excess gas builds up in the blood stream during a long deep and is not allowed to escape. Sperm whales are equipped with special blood vessels near the brain called retia mirabilia (2), whose sole purpose is to filter out the bubbles from long dives. Additionally, they have a protein that stores large amounts of oxygen in their muscle tissue. However, even with these special vessels, sperm whale bones have been found with lesions and pits, and tissue remains have been found with bubbles, indicating the whales may have suffered mild, but chronic, decompression sickness over the course of their lives. Scientists suggest that sonar from ships may cause these great creatures to become scared and ascend too quickly (4). Despite this hazard, sperm whales have a life expectancy of over 70 years.

Diet and Ecology
The great sperm whales are the largest carnivores on earth. Their main food sources include deep-water organisms, including fish, shark, skate, octopus, and giant squid (1). In fact, sperm whales often have a myriad of scars from the suction cups of giant squid. Sperm whales consume about one ton of food each day (1).

Sperm whales are social creatures, often found in groups. The groups either compose of numerous females and calves with a few bulls, or groups of young males (5). They are distributed nearly globally, from the equator to the pack ice of both hemispheres. They are usually found in deep waters far from land.

Whale Hunting
In the past, sperm whales were the focus of commercial hunts in the 1700's and 1800's. Sperm whales were sought after for three main reasons - whale oil, spermaceti, and ambergris. Whale oil comes from the whale's thick coat of blubber. The oil was used for oil in lamps, lubrication, and soap. Spermaceti was the most valuable part of a sperm whale. This waxy substance was used for high quality candle making and for medical and cosmetic ointments (6). Ambergris is a rare substance that forms around lodged squid beaks in a sperm whale's intestines (gross!)(6). Ambergris was, and still is, used to make perfumes and aphrodisiacs.

Although Sperm whales have been extensively hunted in the past, today their populations appear stable, however, they have been listed as endangered since 1970, and are also protected by the Marine Mammal Protection act of 1972 (5).

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1. American Cetacean Society (March 2004) AMERICAN CETACEAN SOCIETY FACT SHEET - SPERM WHALE
acsonline - Sperm Whale Fact Pack

2. Carlson Lisa, Schuler Amy, Smith Vanessa How low can you go? The Physiiology of Deep Diving Adaptations of Whales
https://www.uwrf.edu/BIOL/Index.cfm

3. Halsey Lewis (2002) Ultimate Divers University of Birmingham, UK
http://www.biosciences.bham.ac.uk/

4. Kettlewell, Julianna (November 23, 2004) BBC NEWS Whales 'suffer from the bends'
http://news.bbc.co.uk/2/hi/science/nature/4122119.stm

5. National Marine Fisheries Service Sperm Whales (Physeter macrocephalus) - Office of Protected Resources - NOAA Fisheries
http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/spermwhale.htm

6. World Wild Life Fund (2007) Whales and Dolphins > Sperm Whale
http://www.worldwildlife.org/cetaceans/subspecies/subspecies_sw.cfm

Carrol, R. (1988). Vertebrate Paleontology and Evolution. NY: W.H. Freeman & Company.

Mchedlidze G.A.; Translated by Chakravarthy, R. (1984). General Features of the Paleobiological Evolution of Cetacea. New Delhi: Oxonian Press. Translated for Smithsonian Institution Libraries.

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Recommended Books

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The Cultural Lives of Whales and Dolphins
By: Whitehead and Rendell, 2015
This intermediate level book focuses on the fascinating social aspects of whales (cetacean culture). This is a must read for anyone interested in complex whale vocalizations, social learning, and other behaviors.

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Sperm Whale Fossil Teeth:

Fortunately, Sperm whales are the largest odontocetes (Toothed Whales). So, due to the size, an isolated tooth is easy to assign to the sperm whale superfamily Physeteroidea, which contains the Physeteroidea family and the Kogiidae family.

Unfortunately, after the superfamily designation, sperm whale tooth identification breaks down, and here's why...

First, there is tremendous variation among the teeth of individual sperm whales. For example, the living species P. macrocephallus has teeth that range in size anywhere from an inch to a foot. These teeth can be curved or straight. They can have large roots or small roots. They can be cone shaped or flattened. Almost every tooth in a single mouth is different from the other teeth.

Secondly, in the past, there were around 14 genera of sperm whales, compared to the 2 genera today. Many of these 14 genera contain teeth that vary as wildly as the living species.

The fossil whale paper states this best, "Since overlaps in sizes, shapes, and surface textures do not correlate with one another, these aspects of external appearance cannot be used to categorize sperm whale taxa." (Whitmore, p. 238).

In other words, throw all identification notions out the window. Unless you have a skull attached to the fossil tooth, the proper way to label a sperm whale tooth is to keep it at the superfamily level: Physeteroidea indet.

Whitmore, Frank, C., and Kaltenbach, James A. (2008). Neogene Cetacea of the Lee Creek Phosphate Mine, North Carolina. In: Geology and Paleontology of the Lee Creek Mine, North Carolina, IV. C. E. Ray, D. J. Bohaska, I. A. Koretsky, L. W. Ward, and L. G. Barnes eds. Virginia Museum of Natural History Special Publication, No 14. VMNH Publications, Martinsville, V.A. 2008. Smithsonian Institution Press, Washington D.C. pp. 181-269.

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Sample Sperm Whale Teeth Fossils
Physeteroidea indet.