Sperm Whales and Monodonts

Cetacean Family

  • Physeteridae
  • Kogiidae
  • Monodontidae

Families and Species within this grouping

  • Physeteridae:  Sperm Whale (Physeter macrocephalus)
  • Kogiidae: Pygmy Sperm Whale (Kogia breviceps), Dwarf Sperm Whale (Kogia sima)
  • Monodontidae:  Beluga (Delphinapterus leucas), Narwhal (Monodon monoceros)

Physeteridae Defining Characteristics

  • Square, asymmetrical head (takes up 1/3 of body length)
  • Males can reach 60ft (18.3m) and weigh 125,000lbs (56,699kg). 
  • Females average 36 ft (11 m), 33,000 lbs (14,967 kg)
  • 36 – 50 large cone-shaped teeth in lower jaw, mainly in males
  • Blubber is nearly 14” thick
  • Hunt and navigate by echolocation
  • Eat squid, smaller squid, fish, sharks, crabs, octopus
  • Color ranges from dark gray, black, white (albino)
  • Communicate with patterned clicks
Sperm Whale
Sperm Whale

Interesting Facts

  • Dive depths of more than a mile
  • Can stay underwater for more than an hour
  • Pregnancy lasts 14 – 16 months
  • Interval between births is 5 – 7 years
  • Dive deeper than any other whale
  • Females do not dive as deep as males
  • The strongest social ties are between mothers and calves
  • Teeth don’t emerge until approximately 10 years of age

Habitat Range

  • Found in oceans worldwide

Threats to Survival

  • Humans
  • Entanglement
  • Collisions with boats

Life Expectancy

  • Maximum estimated expectancy is 77 years

Kogiidae Defining Characteristics

  • Blunt, squarish head
  • Spermaceti organ on top of skull
  • Asymmetrical skulls
  • Single blowhole, slightly offset to the left side of the head
  • Short underslung jaw
  • Maximum length of 12 ft (3.8m)
  • Feed mainly on squid, also on crabs
  • Shark-like appearance
  • Brownish to dark bluish-gray with a whitish to pinkish belly
  • Gill-like marking behind each eye
  • Have a sac in their intestines that expels a reddish, inky fluid


Habitat Range

  • Not well known, seems to prefer deep, off-shore waters in temperate and tropical zones


Threats to Survival

  • Entanglement in fishing gear
  • Ship strike
  • Ingestion of marine debris
  • Noise pollution


Life Expectancy

  • Estimate of 20-25 years




illustration of Pygmy whale






Illustration by Uko Gorter

Pygmy (Kogia breviceps)

Interesting Facts

  • Eat a wider variety of squid than Dwarf sperm whales
  • 20-32 sharp, conical teeth in lower jaw




Dwarf whale

Illustration by Pieter Folkens

Dwarf (Kogia sima)

Interesting Facts

  • Smallest animal called ‘whale’
  • Dorsal fin is larger than that of Pygmy sperm whale
  • More likely to forage along the coastline than Pygmy sperm whales
  • 14-26 sharp, conical teeth in lower jaw


Monotontidae Defining Characteristics
(Belugas and Narwhals)

  • Medium sized animals 13 – 19 ft (4 – 6m) in length
  • Weigh up to 3500 lbs (1600 kg)
  • No dorsal fin
  • Found in high latitudes
  • Travel in groups
  • Feed near the bottom
  • Feed on fish, squid, crustaceans, octopi, worms
  • White to white – gray coloring
  • Very vocal with others of their species
  • Approximately 5 ft (1.3m) at birth
“Two Views, Narwhal and Shark”
William Scoresby. NBWM Kendall Collection

Habitat Range

  • Arctic Ocean
  • Freshwater rivers that empty into the Arctic

Threats to Survival

  • Orcas
  • Polar Bears
  • Pollution
  • Humans

Life Expectancy

  • Estimated 25 – 50 years

Beluga (Delphinapterus leucas)
Interesting Facts

  • Tiny eyes
  • Rounded melon
  • Thick blubber
  • Well-defined neck
  • No neck vertebrae are fused together
  • Wide, deeply notched flukes
  • Short, round, wide flippers
  • Have 34 teeth designed to grab and tear prey
  • Teeth are found in upper and lower jaws
  • Belugas do well in captivity/being observed by humans
  • Usually dive about 3-15 minutes while diving for food
  • Can dive a depth of about 1,300 – 2,100 feet (396 – 640 m)
  • Make clicks, squeals, chirps, grunts, screeches and whistles
  • Pregnancy lasts 14 – 16 months
  • Births take place every 2-3 years
Photo by latimesblogs.latimes.com


Narwhal (Monodon monoceros)
Interesting Facts

  • White with green and brown spotting
  • Become white in old age
  • All narwhals have 2 teeth in their upper jaw
  • After the first year of a male narwhal’s life, its left tooth grows outward, spirally, through the face
  • Tooth can be 7-10 feet (2-3 m) long
  • Tusk likely used by males to establish hierarchy
  • Tusk has exceptional sensory capabilities and can detect changes in the environment, which may help in finding food
  • 1 out of every 1,000 will have two tusks
  • 15% of females will grow a tusk
  • Some groups consist of just one sex and others contain both sexes
  • Many pods may travel together, forming very large groups
  • Rely on sound production and reception to navigate, communicate, locate breathing holes, and hunt in dark or murky waters
  • Make squeals, clucks, mews, chirps, trills, and bell-like tones
  • Can dive down to 1500 m deep
  • Duration of a narwhal dive is from 7-25 minutes
  • Pregnancy lasts 10 – 16 months
  • Births take place every 3 years







 Cited Sources

  • http://www.enchantedlearning.com/subjects/whales/species/Beluga.shtml
  • http://www.vanaqua.org/learn/aquafacts/cetaceans/belugas
  • http://jason-parent.suite101.com/the-alaskan-beluga-whale-an-endangered-species-a147568
  • http://library.thinkquest.org/3500/Narwhal.html
  • http://www.enchantedlearning.com/subjects/whales/species/Narwhal.shtml
  • http://www.enchantedlearning.com/ngifs/Narwhal_bw.GIF
  • http://www.Carnivoraforum.com
  • http://www.nmfs.noaa.gov/pr/species/
  • Michelle D. Staudinger, Ryan J. McAlarney, William A. McLellan, D. Ann Pabst. Foraging ecology and niche overlap in pygmy (Kogia breviceps) and dwarf (Kogia sima) sperm whales from waters of the U.S. mid-Atlantic coast. Marine Mammal Science, 2014; 30 (2) 626 DOI: 10.1111/mms.12064
  • Nweeia, M. T., Eichmiller, F. C., Hauschka, P. V., Donahue, G. A., Orr, J. R., Ferguson, S. H., Watt, C. A., Mead, J. G., Potter, C. W., Dietz, R., Giuseppetti, A. A., Black, S. R., Trachtenberg, A. J. and Kuo, W. P. (2014), Sensory ability in the narwhal tooth organ system. Anat. Rec., 297: 599–617.
  • doi:10.1002/ar.22886
  • Cox, Vic. Whales & Dolphins. S.l.: Book People, 1990. Print.
Researched and written by Sharmaine Flint, NBWM Apprentice, March 2012. Updated in August 2016.