A bactrian camel. This species has two distinct humps, compared to the dromedary, which has one.

A hump is a round mass of fat or muscle that occurs naturally in many animal species, especially in mammals. Humps often serve as fat reserves, allowing the animal to survive without food for extended periods of time. A hump can also help an animal to regulate body heat in hot climates. Some humps consist of muscle instead of fat, which can help the animal dig through hard soil, hold up a heavy head, or maneuver around in snow.

Morphology

An animal's hump is formed by neural spines on the thoracic vertebrae. Despite only being known from the fossil record, the woolly mammoth and species of the genus Titanotylopus are assumed to have had humps due to the presence of such spines in their skeletons.[1] In the gaur, the hump is formed solely because of the skeletal structure, as its third to eleventh vertebrae have such spines.[2] In both dromedaries and bactrian camels, humps are attached to the adipose tissue in the dorsal region, and fixed in place by the trapezius and rhomboid muscles.[3]

A female dromedary, or one-humped camel, with her newborn. Note that the newborn has not yet developed its hump.

Humps which mostly contain fat can shrink or disappear depending on conditions. When camels are born, the humps are small and may appear deflated, but will grow as the calf begins to eat solid food.[4] Adult camels that suffer extreme stress, such as heavy parasite loads, may lose their humps due to depletion of fat reserves.[5] Captive plains bison may arch their backs (or "hump up") as a stress response, especially if in close confinement, which can create the illusion that their actual hump is much lower at the shoulders.[6]

Humps can take different forms, even between closely related species. The dromedary camel has only one hump, while the bactrian camel has two. This may be due to differences in fat metabolism rates, as the two-humped bactrian evolved lipid metabolism more rapidly.[7] Yaks have humps comparable to the breastbone of a bird, while zebus have lump-like humps; when the two are crossbred, the yak's hump gene is dominant over the zebu's.[8]

In some cattle breeds, like the Drakensberger and Nguni, the hump is sexually dimorphic, with only bulls having one. In other breeds, like the Boran, both sexes have a hump, but it is larger in the male.[2]

Kinds of humps

Fat

Most of a camel's fat is stored in its hump, which can weigh up to 80 pounds[9] (36.3 kg). This fat store allows it to go long periods of time without eating. If a camel continuously uses its fat stores without replenishing, the humps will eventually become flaccid in appearance.[4] The hump also aids with heat regulation, as nearly all of its fat is stored in the hump, as opposed to even distribution throughout the body.[10] During the day, the camel's hump stores heat, which is then dissipated through the camel's body at night, allowing for better retention of water compared to other thermoregulation methods.[11]

Muscle

The grizzly bear has a distinct hump between its shoulders, made out of muscle.

The brown bear has a hump between its shoulders,[12] a distinction from other bear species.[13][14] This hump is formed by large muscles, allowing for a wide range of motion,[15] which the bear mainly uses to put pressure on the soil as it digs for food.[16] The bison also has a hump between its shoulders, made almost entirely of muscle and supported by long skeletal spines. The bison hump's purpose is to hold up the animal's large head,[2] and also enables the animal to use its head as a snow shovel in the winter, swinging it side to side with its hump muscles.[17][18] Such foraging behavior sets the bison apart from other ungulates, which typically use their feet to scrape away snow.[19] Moose, similarly, have a shoulder hump of muscle that is necessary to hold up their large head and, in males, antlers.[20]

Other hump types

A common misconception says that camels store water in their humps. This is not true, however; as stated above, the humps store fat. If a camel is under stress, it will extract water from its rumen.[4] The fat reserves themselves keep the camel from becoming thirsty, allowing for greater conservation of water.[21]

Non-mammalian humps

Dinosaurs

It has been theorized that the neural spines of Spinosaurus, Ouranosaurus, and other dinosaurs with similar spines had humps, rather than the sailfins they are commonly depicted as having. If true, such humps would aid with heat regulation, storing of lipids for egg production, and storing fat for long migrations.[22] Concavenator corcovatus is named for its hump (the name means "hunchback hunter from Cuenca"), but its use is debated, with theories including heat regulartion, attracting mates, intimidating rivals, or fat storage.[23]

Fish

The humpback chub is an example of a fish that has a hump.

Some fish species have humps, with their makeup varying. The nuchal hump of a humpback chub (from which the species gets its name) is made up almost entirely of skeletal muscle, and may exist to reduce the chub's vulnerability to predators.[24] The flowerhorn cichlid is an ornamental aquarium fish which is bred for its very large nuchal hump. Some breeders may artificially increase the hump's size by injecting it with hormones or feeding the flowerhorn a hormone-rich diet.[25]

Male salmon of the Oncorhynchus genus have dorsal humps, which were once thought to consist of cartilage, but is now known to be formed by increases in connective tissues and neural spine growth.[26] Of this genus, sockeye and pink salmon develop the biggest humps, which are mostly made of connective tissue[27] and which decrease in lipid content with age.[26] In contrast, the closely related masu and chum salmon have smaller humps that are mostly formed by bone tissue.[27]

Hinderance

A hump can cause stress on the spine. In brown bears, a hump may cause lesions on the cranial thoracic vertebrae, the vertebra most directly near it. Captive bears with such a condition are usually euthanized.[28] The gudaali is a zebu breed developed in Africa, which, compared to other breeds, has a smaller body and larger hump. This combination makes locomotion difficult for the animal.[29]

Zebu cows with especially large humps may have reduced fertility.[30]

In human culture

The plains bison has a hump of muscle, which holds up its large head and helps it shovel snow in the winter.

Humped animals appear in some cave paintings, which is of interest to paleontologists, who can use such depictions to better understand what extinct fauna looked like. Some cave paintings depict woolly mammoths as being humped, which is corroborated by the humps present on frozen specimens.[1] Similarly, the cave bear is depicted as having a shoulder hump in some French cave paintings.[31] Because of how prominently humps are drawn, it has been theorized that ancient painters used the hump as the starting point when drawing.[32]

Humps may not be accurately created in taxidermy. William Temple Hornaday lamented that when stuffing plains bison, there is a tendency to make the hump "a huge, thick, rounded mass like the hump of a dromedary," as opposed to the "high and sharp" muscle hump that bison actually have.[6]

The fat humps of camels are a source of meat in some cultures. Khlii, a camel meat dish from Algeria, is prepared in a mixture of fat from the camel's hump and kidneys.[33] Camel hump fat is high in saturated fatty acids, with as much as 64.4% of the hump's weight basis consisting of them, and another 33.1% of its weight basis is monounsaturated fats.[34] Bison humps, despite consisting of muscle instead of fat, are also considered a delicacy by some; William Temple Hornaday called sliced and fried bison hump "a dish fit for the gods".[6]

The zebu, a breed of cattle, is an example of a domesticated animal with a hump.

In markets where zebu are valued, humps can provide the breeder with higher income. In such markets, cattle may be selectively bred to have a large hump, so as to indicate a pure zebu bloodline.[30] Siddi breeders backcross herds that have mixed too much with humpless cattle, selcting for taller bulls with larger humps, as these will be worth more than humpless bulls.[29]

Certain landforms may be named due to their resemblance of animal humps. Camel's Hump in Vermont and Buffalo Hump in Idaho are two such examples. Humans may also take their names from animal humps, such as the Comanche war chief Buffalo Hump. Some HIV-1 patients develop a fat deposit nicknamed a "buffalo hump", though this forms on the patient's neck,[35][36] as opposed to between the shoulders in an actual bison.

See also

References

  1. 1 2 Kurtèn, Björn; Anderson, Elaine (1980). Pleistocene Mammals of North America. Columbia University Press.
  2. 1 2 3 Friend, John B. (1978). Cattle of the World. Blandford Press.
  3. ↑ Endo, Hideki (21 January 2000). "Hump Attachment Structure of the Two-Humped Camel (Camelus bactrianus)". Journal of Veterinary Medical Science. 62 (5).
  4. 1 2 3 Pycraft, W.P. (August 1929). "The Camel's Hump". Scientific American. 141 (2): 137 – via JSTOR.
  5. ↑ Faye, Bernard (30 October 2025). "Body Measurements and Body Condition Scoring in Bactrian Camels". Animals. 15 (21) – via PubMed.
  6. 1 2 3 Hornaday, William Temple (1889). The Extermination of the American Bison, With a Sketch of Its Discovery and Life History. Washington, D.C.: US Government Publishing Office. p. 41.
  7. ↑ Wu, Huiguang (21 October 2014). "Camelid genomes reveal evolution and adaptation to desert environments". Nature Communications. 5 (5188).
  8. ↑ Zawadowsky, M.M. (October 1931). "Zebu-Yak Hybrids". Journal of Heredity. 22 (10).
  9. ↑ Nuwer, Rachel (21 October 2014). "Why the Alpaca Has No Humps". Smithsonian Magazine.
  10. ↑ Price, Jo (6 January 2025). "How did the camel get its hump?". BBC Wildlife Magazine.
  11. ↑ McFarland, David, ed. (1982). The Oxford Companion to Animal Behavior. Oxford University Press. p. 563.
  12. ↑ Pasitschniak-Arts, Maria (23 April 1993). "Ursus arctos". Mammalian Species (439). American Society of Mammalogists: 2.
  13. ↑ Larivière, Serge (23 January 2001). "Ursus americanus". Mammalian Species. 647. American Society of Mammalogists: 2. Cinnamon or brown color phases of U. americanus can be differentiated from U. arctic by lack of a prominent shoulder hump.
  14. ↑ DeMaster, Douglas P.; Sterling, Ian (8 May 1981). "Ursus maritimus". Mammalian Species (145). American Society of Mammalogists: 2. Typically the body of a polar bear is stocky but lacks a shoulder hump.
  15. ↑ Huber, Duro; van Manen, Frank T. (2019). "Bear Morphology". In Vonk, Jennifer; Shackleford, Todd K. (eds.). Encyclopedia of Animal Cognition and Behavior. Switzerland: Springer Publishing. p. 5.
  16. ↑ "Brown Bear Frequently Asked Questions". Katmai National Park and Preserve. 29 October 2024.
  17. ↑ Meyers McClintick, Lisa (4 January 2026). "A bison's hump helps it plow through the snow". The Minnesota Star Tribune. Archived from the original on 13 January 2026. Retrieved 23 July 2026.
  18. ↑ Ecosystems Mission Area. "Bison in winter". US Geological Service.
  19. ↑ "Bison Ecology". Yellowstone National Park. National Park Service. 4 May 2026.
  20. ↑ Bullock, Corey (8 October 2021). "Moose with arrow in back hump spotted walking around near Fernie". Victoria News. Retrieved 23 July 2026.
  21. ↑ "What do camels store in their humps? And other camel superpowers". World Wildlife Fund. Retrieved 19 July 2026.
  22. ↑ Bailey, Jack Bowman (November 1997). "Neural spine elongation: tailbacks or buffalo-backs?". Journal of Paleontology. 71 (6). The Paleontological Society: 1124 – via Cambridge University Press.
  23. ↑ Owen, James (10 September 2010). "Hunchback Dinosaur Found: "Carnivorous Camel"". National Geographic. Retrieved 23 July 2026.
  24. ↑ Ward, David; Ward, Michael B. (5 February 2020). "What's in the hump of the humpback chub?". Western North American Naturalist. 80 (1).
  25. ↑ Lorenz, Tom (November 2009). "Flower Power: Are Flowerhorns Good for the Hobby?". Tropical Fish Magazine. Retrieved 23 July 2026.
  26. 1 2 Susuki, Kenta (10 December 2013). "Dorsal hump morphology in pink salmon (Oncorhynchus gorbuscha)". Journal of Morphology. 275 (5).
  27. 1 2 Susuki, Kenta (2 May 2017). "Comparative anatomy of the dorsal hump in mature Pacific salmon". Journal of Morphology. 278 (7).
  28. ↑ Rosenzweig Büeller, Ariela (2016). "Dorsal Laminectomy to Relieve Spinal Cord Compression in a Captive Syrian Bear (Ursus arctos syriacus)". Journal of Zoo and Wildlife Medicine. 47 (4). American Association of Zoo Veterinarians: 1106.
  29. 1 2 Boutrais, Jean (2007). "The Fulani and Cattle Breeds: Crossbreeding and Heritage Strategies". Africa: Journal of the International African Institute. 77 (1). Cambridge University Press.
  30. 1 2 Sanders, James O. (1 June 1980). "History and Development of Zebu Cattle in the United States". Journal of Animal Science. 50 (6).
  31. ↑ Stiner, Mary C. (April 1998). "Cave Bear Ecology and Interactions with Pleistocene Humans". Ursus. 11: 13.
  32. ↑ Sieveking, Anne (1962). The Caves of France and Northern Spain, A guide. London: Vista Books. p. 28.
  33. ↑ Benyagoub, E.; Kerkoub, M.; Bessadet, C. (1 July 2025). "An Investigation Into the Traditional Processing of Camel Meat as Khlii: A Dried, Cooked, and Fatty Meat from Southwestern Algeria". Asian Journal of Dairy and Food Research: 3.
  34. ↑ Sahraoui, Namia (June 2015). "Fatty Acids Profile of the Dromedary Hump in Algeria". Journal of Camel Practice and Research. 22 (1): 27.
  35. ↑ Lo, J.C.; Mulligan, K.; Tai, V.W.; Schambelan, M. (21 March 1998). ""Buffalo hump" in men with HIV-1 infection". The Lancet. 351 (9106) – via PubMed.
  36. ↑ Ceccarelli, Giancarlo (17 February 2011). "Development of Buffalo Hump in the course of antiretroviral therapy including raltegravir and unboosted atazanavir: a case report and review of the literature". Journal of Medical Case Reports. 5 (70) – via PubMed.