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{{Short description|Subspecies of bird}} |
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{{Subspeciesbox |
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{{subspeciesbox |
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| name = Masai ostrich |
| name = Masai ostrich |
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| image = Ostrich Ngorongoro 05.jpg |
| image = Ostrich Ngorongoro 05.jpg |
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| status = LC |
| status = LC |
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| status_system = IUCN3.1 |
| status_system = IUCN3.1 |
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| status_ref = <ref name=IUCN>{{cite iucn | |
| status_ref = <ref name=IUCN>{{cite iucn | author = [[BirdLife International]] | title = ''Struthio camelus massaicus'' | volume= 2018 | year = 2018 | doi = 10.2305/IUCN.UK.2018-2.RLTS.T45020636A132189458.en}}</ref> |
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| genus = Struthio |
| genus = Struthio |
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| species = camelus |
| species = camelus |
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The Masai ostrich (''Struthio camelus massaicus''), also known as the '''East African ostrich''' is a red-necked subspecies variety of the [[common ostrich]] and is endemic to [[East Africa]].<ref>{{Cite web|url=https://avibase.bsc-eoc.org/species.jsp?avibaseid=BF8ED7FA|title=Struthio camelus massaicus (African Ostrich (North African)) - Avibase|website=avibase.bsc-eoc.org|access-date=2019-12-05}}</ref><ref name=":0">{{ |
The '''Masai ostrich''' ('''''Struthio camelus massaicus'''''), also known as the '''East African ostrich''' is a red-necked subspecies variety of the [[common ostrich]] and is endemic to [[East Africa]].<ref>{{Cite web|url=https://avibase.bsc-eoc.org/species.jsp?avibaseid=BF8ED7FA|title=Struthio camelus massaicus (African Ostrich (North African)) - Avibase|website=avibase.bsc-eoc.org|access-date=2019-12-05}}</ref><ref name=":0">{{cite journal |last1=Seddon |first1=Philip J. |last2=Soorae |first2=Pritpal S. |title=Guidelines for Subspecific Substitutions in Wildlife Restoration Projects |journal=Conservation Biology |date=February 1999 |volume=13 |issue=1 |pages=177–184 |doi=10.1046/j.1523-1739.1999.97414.x |s2cid=84578693 }}</ref> It is one of the largest birds in the world, second only to its sister subspecies ''Struthio camelus camelus''.<ref name=":1">{{Cite book|title=The Ostrich Communal Nesting System.|last=Bertram, Brian C. R.|date=2014|publisher=Princeton University Press|isbn=978-1-4008-6314-3|location=Princeton|oclc=884012871}}{{pn|date=October 2021}}</ref> Today it is farmed for [[Ostrich egg|eggs]], meat, and feathers.<ref name=":2">{{cite thesis |last1=Magige |first1=Flora John |title=The ecology and behaviour of the Masai Ostrich (Struthio camelus massaicus) in the Serengeti Ecosystem, Tanzania |date=2008 |hdl=11250/244464 }}</ref><ref name="ReferenceA">{{cite journal |last1=McKeegan |first1=D.E.F. |last2=Deeming |first2=D.C. |title=Effects of gender and group size on the time-activity budgets of adult breeding ostriches (Struthio camelus) in a farming environment |journal=Applied Animal Behaviour Science |date=January 1997 |volume=51 |issue=1–2 |pages=159–177 |doi=10.1016/S0168-1591(96)01096-9 }}</ref> |
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== Taxonomy == |
== Taxonomy == |
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=== Subspecies === |
=== Subspecies === |
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The Masai ostrich is one of the |
The Masai ostrich is one of the three extant subspecies of ostrich currently inhabiting Africa, including the nominative ostrich (''[[North African ostrich|S. c. camelus]]'') found across northern Africa and the South African ostrich (''[[South African ostrich|S. c. australis]]''). It is considered one of the two red-necked forms of ostrich, along with ''S. c. camelus'', as opposed to the two blue-necked forms (''S. c. australis'' and ''S. c. molybdyphanes'').<ref name=":0" /> |
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Comparative restriction-enzyme analysis of [[mitochondrial DNA]] (mtDNA) found the Masai ostrich, though genetically distinct, is most closely related to ''S. c. australis'', despite their geographical separation, and least genetically related to ''S. c. molybdophanes'', despite habitat overlap.<ref name=":3">{{Cite journal| |
Comparative restriction-enzyme analysis of [[mitochondrial DNA]] (mtDNA) found the Masai ostrich, though genetically distinct, is most closely related to ''S. c. australis'', despite their geographical separation, and least genetically related to ''S. c. molybdophanes'', despite habitat overlap.<ref name=":3">{{Cite journal|last1=Freitag|first1=Stefanie|last2=Robinson|first2=Terence J.|date=1993|title=Phylogeographic Patterns in Mitochondrial DNA of the Ostrich (Struthio camelus)|journal=The Auk|volume=110|issue=3|pages=614–622|doi=10.2307/4088425|jstor=4088425|doi-access=free}}</ref><ref name=":4">{{cite journal |last1=Miller |first1=Joshua M. |last2=Hallager |first2=Sara |last3=Monfort |first3=Steven L. |last4=Newby |first4=John |last5=Bishop |first5=Kelley |last6=Tidmus |first6=Scott A. |last7=Black |first7=Peter |last8=Houston |first8=Bill |last9=Matthee |first9=Conrad A. |last10=Fleischer |first10=Robert C. |title=Phylogeographic analysis of nuclear and mtDNA supports subspecies designations in the ostrich (Struthio camelus) |journal=Conservation Genetics |date=April 2011 |volume=12 |issue=2 |pages=423–431 |doi=10.1007/s10592-010-0149-x |s2cid=28575743 }}</ref> Explanations for these counterintuitive findings are that while the [[Miombo|Brachystegia]] or “miombo” woodlands currently serves as a zoogeographic barrier separating northern and southern ostrich populations, it is theorized that this barrier was not as dense and effective throughout evolutionary time and once allowed for brief periods of intraspecific breeding between ''S. c. massaicus'' and ''S. c. australis'' populations.<ref name=":3" /> Conversely, the genetic divergence observed between ''S. c. massaicus'' and ''S. c. molybdophanes,'' albeit a lack of any zoogeographic barrier, is thought to be due to the ecological differences in behavioral and reproductive cues between these populations. These differences were substantial enough to prevent intraspecific breeding throughout time.<ref name=":3" /><ref name=":4" /> These same studies found ''S. c. massaicus'' to significantly differ genetically from ''S. c. camelus'' subspecies''.''<ref name=":3" /><ref name=":4" /> |
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Although the now extinct subspecies ''[[Arabian ostrich|S. c. syriacus]]'' was determined to also be a red-necked form of ostrich based on historical evidence, similar analysis of mtDNA found the Masai ostrich to not be as close of a relative to ''S. c. syriacus'' compared to ''S. c. camelus''.<ref>{{ |
Although the now extinct subspecies ''[[Arabian ostrich|S. c. syriacus]]'' was determined to also be a red-necked form of ostrich based on historical evidence, similar analysis of mtDNA found the Masai ostrich to not be as close of a relative to ''S. c. syriacus'' compared to ''S. c. camelus''.<ref>{{cite journal |last1=Robinson |first1=Terence J. |last2=Matthee |first2=Conrad A. |title=Molecular genetic relationships of the extinct ostrich, Struthio camelus syriacus: consequences for ostrich introductions into Saudi Arabia |journal=Animal Conservation |date=August 1999 |volume=2 |issue=3 |pages=165–171 |doi=10.1111/j.1469-1795.1999.tb00062.x |s2cid=85959044 }}</ref> |
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== Description == |
== Description == |
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=== Anatomy === |
=== Anatomy === |
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Adult males are 2. |
Adult males are 2.1–2.7 m in height and can weigh up to 145 kg; females are typically slightly smaller in size.<ref name=":2" /> They have large eyes (50 mm across), long eyelashes, and exceptional vision.<ref name=":5">{{cite journal |last1=Hurxthal |first1=Lewis M. |year=1986 |title=Our gang, ostrich style |journal=Natural History |volume=95 |pages=34–41, 94 |url=https://www.naturalhistorymag.com/htmlsite/master.html?https://www.naturalhistorymag.com/htmlsite/editors_pick/1986_12_pick.html }}</ref> Their heads are relatively small compared to their body and are covered in degenerated feathers that give the upper two-thirds of their elongated neck an almost naked appearance.<ref name=":6">{{Cite book|title=Grzimek's Animal life encyclopedia |last1=Grzimek |first1=Bernhard |date=1972–75|publisher=Van Nostrand Reinhold Co|isbn=0-442-78478-3|location=New York|oclc=425737}}{{pn|date=October 2021}}</ref> The skin of the neck and thighs of male Masai ostriches is bare and pink in color, which intensifies to an almost reddish hue during mating season.<ref name=":1" /> |
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| ⚫ | Their large size prevents the capability of flight, but this is compensated by their exceptionally long and muscular legs, which allow for maximum running speeds of up to 60–70 km/h.<ref>{{Cite book|title=The birds of Africa |last1=Brown |first1=Leslie |date=1982|publisher=Academic Press |last2=Urban |first2=Emil K. |last3=Newman |first3=Kenneth |isbn=0-12-137301-0|location=London|oclc=8982298}}{{pn|date=October 2021}}</ref>[[File:Masai Ostrich (7515523078).jpg|thumb|Male and female Masai ostrich (''S. c. massaicus)'' side-by-side comparison''.''|alt=|left]] |
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| ⚫ | Their large size prevents the capability of flight, but this is compensated by their exceptionally long and muscular legs, which allow for maximum running speeds of up to |
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==== Plumage ==== |
==== Plumage ==== |
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The feathers of the Masai ostrich lack [[Feather|barbs]], which gives them a soft, downy appearance.<ref name=":1" /> Similar to other ostrich subspecies, they possess approximately |
The feathers of the Masai ostrich lack [[Feather|barbs]], which gives them a soft, downy appearance.<ref name=":1" /> Similar to other ostrich subspecies, they possess approximately 50–60 tail feathers, 16 primaries, 4 alular, and 20–23 secondary feathers. The wing and tail feathers have evolved to serve as decorative plumes for courtship display rather than flight.<ref name=":6" /> |
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For males, the majority of the body is covered in black feathers. White feathers appear along the tips of the wings, tail, and form a small ring partway up the neck that separates the black body feathers from bare neck skin. The white tail feathers are often discolored from dirt and appear reddish-brown.<ref name=":1" /> |
For males, the majority of the body is covered in black feathers. White feathers appear along the tips of the wings, tail, and form a small ring partway up the neck that separates the black body feathers from bare neck skin. The white tail feathers are often discolored from dirt and appear reddish-brown.<ref name=":1" /> |
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==== Reproductive/Excretory organs ==== |
==== Reproductive/Excretory organs ==== |
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[[File:Male Masai ostrich.png|thumb|Example of male Masai ostrich everting penis to excrete liquid|alt=|left]] |
[[File:Male Masai ostrich.png|thumb|Example of male Masai ostrich everting penis to excrete liquid|alt=|left]] |
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Unlike most avian species, male ostriches have a retractable penis that averages 20 |
Unlike most avian species, male ostriches have a retractable penis that averages 20 cm in length and everts during defecation, urination, and copulation.<ref name=":1" /><ref name=":6" /> The ostrich is the only bird to void urine separate from defecation due to the muscular sphincter-like folds located within the [[cloaca]].<ref name=":6" /><ref>{{cite journal |last1=Warui |first1=C. N. |last2=Macharia |first2=R. G. |last3=Mwangi |first3=D. K. |last4=Macheru |first4=P. W. |last5=Moilo |first5=J. |title=Observations on the morphology of the cloacal region of the African ostrich (Struthio camelus massaicus) |journal=The Kenya Veterinarian |date=1998 |volume=23 |pages=53–55 |hdl=11295/65982 |hdl-access=free }}</ref> |
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==== Environmental adaptations ==== |
==== Environmental adaptations ==== |
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Several physiological adaptations have evolved to allow the Masai ostrich to live in the extreme arid conditions of [[Sub-Saharan Africa]]. Their feathers have specialized to work as efficient insulators for proper [[thermoregulation]] during both hot and cold climates.<ref>Louw |
Several physiological adaptations have evolved to allow the Masai ostrich to live in the extreme arid conditions of [[Sub-Saharan Africa]]. Their feathers have specialized to work as efficient insulators for proper [[thermoregulation]] during both hot and cold climates.<ref>{{cite journal |last1=Louw |first1=Gideon N., Belonje, Peter C. & Coetzee Hendrik J. |title=Renal function, respiration, heart rate and thermoregulation in the ostrich (Struthio camelus) |journal=Scientific Papers of the Namib Desert Research Station |date=1 January 1972 |volume=1972 |issue=42 |pages=43–54 |hdl=10520/AJA0000008_220 |url=https://journals.co.za/doi/abs/10.10520/AJA0000008_220 }}</ref> Increased [[aldosterone]] release and use of mucus in place of water for excretion of [[uric acid]] promotes water retention in arid environments. Masai ostriches also possess salt-excreting nasal glands which allow for consumption of salt water from [[Salt lake|saline]] and [[soda lake]]s when necessary.<ref name=":7">{{cite journal |last1=Cloudsley-Thompson |first1=J. L. |last2=Mohamed |first2=El Rasid Musa |title=Water Economy of the Ostrich |journal=Nature |date=December 1967 |volume=216 |issue=5119 |pages=1040 |doi=10.1038/2161040a0 |bibcode=1967Natur.216.1040C |s2cid=4278385 |doi-access=free }}</ref> |
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== Distribution and habitat == |
== Distribution and habitat == |
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Wild Masai ostriches are located across [[Uganda]], [[Kenya]] and [[Tanzania]].<ref name=":0" /> Denser populations are often found in the semi-arid, open grassy plains of the African [[savanna]].<ref name=":1" /> Despite this preference, they have been known to also inhabit desert, dense brush, and steep rocky mountain environments.<ref name=":6" /> |
Wild Masai ostriches are located across [[Uganda]], [[Kenya]] and [[Tanzania]].<ref name=":0" /> Denser populations are often found in the semi-arid, open grassy plains of the African [[savanna]].<ref name=":1" /> Despite this preference, they have been known to also inhabit desert, dense brush, and steep rocky mountain environments.<ref name=":6" /> |
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== Behavior and ecology == |
== Behavior and ecology == |
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=== Breeding === |
=== Breeding === |
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Masai ostrich breeding season begins around May or June. During this time, the pink hue on male Masai ostriches neck and leg skin intensifies as a form of mating display. Mature males begin to establish territories that are about 2 |
[[File:Male ostrich pink.jpg|thumb|A male Masai ostrich in Naboisho Conservancy, Kenya, showing the characteristic pink hue of a breeding male.]] |
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Masai ostrich breeding season begins around May or June. During this time, the pink hue on male Masai ostriches neck and leg skin intensifies as a form of mating display. Mature males begin to establish territories that are about 2–3 km<sup>2</sup> in area and aggressively defend their domain against other breeding males. They will also construct scrape nests in prior to the arrival of breeding females.<ref name=":5" /> |
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In July, adult female ostriches begin establishing breeding zones that span around 13 |
In July, adult female ostriches begin establishing breeding zones that span around 13 km<sup>2</sup>. These breeding zones overlap with 5–7 male territories, in which males attempt to mate with any adult females that pass through his territory.<ref name=":5" /> |
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==== Communal nesting ==== |
==== Communal nesting ==== |
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[[File:Struthio camelus -Serengeti, Tanzania -female on nest-8.jpg|thumb|Major Female Masai ostrich incubating eggs|alt=]] |
[[File:Struthio camelus -Serengeti, Tanzania -female on nest-8.jpg|thumb|Major Female Masai ostrich incubating eggs|alt=]] |
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Similar to other ostrich subspecies, the Masai ostrich nests in groups and engages in [[Crèche (zoology)|crѐching]] behavior where a single (major) female incubates the eggs of several other (minor) females within a single nest.<ref name=":5" /><ref>{{ |
Similar to other ostrich subspecies, the Masai ostrich nests in groups and engages in [[Crèche (zoology)|crѐching]] behavior where a single (major) female incubates the eggs of several other (minor) females within a single nest.<ref name=":5" /><ref>{{cite journal |last1=Kimwele |first1=C. N. |last2=Graves |first2=J. A. |title=A molecular genetic analysis of the communal nesting of the ostrich (Struthio camelus) |journal=Molecular Ecology |date=19 December 2002 |volume=12 |issue=1 |pages=229–236 |doi=10.1046/j.1365-294x.2003.01727.x |pmid=12492891 |s2cid=32020136 }}</ref> Only 1 out of 3 hens will become a major female, the remaining hens are considered minor females and will not incubate their own eggs.<ref name=":5" /> A nest is initiated when a single major female mates with a territorial male who has already prepared a nesting site and performed a complex mating display.<ref name=":1" /><ref name=":5" /><ref name=":6" /> After she lays the initial clutch, both her and the territorial male assume primary care of the eggs.<ref name=":5" /> The major female lays on average 2 eggs per day and will spend a subsequent 15–90 minutes incubating, then will periodically leave the nest unattended to allow minor females to copulate with the territorial male and lay eggs in the nest. The male will often spend more time incubating the nest than the major female.<ref name=":5" /><ref name=":1" /> An upwards of 18 different minor females will lay eggs in a single major females nest, resulting in an excess of eggs. Since both male and female Masai ostriches are only able to incubate 20–21 eggs at a time, so the major female will eject excess eggs. A reproductive advantage observed in major females is that they are able to recognize their own eggs and will eject minor female eggs in favor of theirs as a necessary way to reduce nest overcrowding.<ref>{{cite journal |last1=Bertram |first1=Brian C. R. |title=Ostriches recognise their own eggs and discard others |journal=Nature |date=May 1979 |volume=279 |issue=5710 |pages=233–234 |doi=10.1038/279233a0 |pmid=440431 |bibcode=1979Natur.279..233B |s2cid=4236729 }}</ref> |
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==== Eggs ==== |
==== Eggs ==== |
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Masai ostrich eggs are large (grapefruit-sized) and white in color.<ref name=":5" /><ref name=":8">{{ |
Masai ostrich eggs are large (grapefruit-sized) and white in color.<ref name=":5" /><ref name=":8">{{cite journal |last1=Magige |first1=Flora John |last2=Moe |first2=Børge |last3=Røskaft |first3=Eivin |title=The white colour of the Ostrich (Struthio camelus) egg is a trade-off between predation and overheating |journal=Journal of Ornithology |date=July 2008 |volume=149 |issue=3 |pages=323–328 |doi=10.1007/s10336-008-0273-2 |s2cid=25321892 }}</ref> They measure 14–16 cm and weigh between 1.0 and 1.6 kg.<ref>{{cite journal |last1=Muwazi |first1=R. T. |last2=Baranga |first2=Jonathan |last3=Kayanja |first3=Frederik I. B. |last4=Schliemann |first4=Harald |title=The oviduct of the ostrichStruthio camelus massaicus |journal=Journal für Ornithologie |date=October 1982 |volume=123 |issue=4 |pages=425–433 |doi=10.1007/BF01643275 |s2cid=42620338 }}</ref> Egg hatching occurs during October and November, when eastern Africa experiences brief periods of rainfall that generates edible plants that are the Masai ostriches primary food source.<ref name=":5" /> Hatchlings are about the size of a domestic chicken hen and are physically precocious, but still require parental care.<ref name=":5" /><ref name=":6" /> |
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The conspicuous size and color of the Masai ostrich eggs makes them an easy target for predation, particularly when major females abandon nests for upwards of two to three weeks prior to incubation.<ref name=":8" /><ref>{{ |
The conspicuous size and color of the Masai ostrich eggs makes them an easy target for predation, particularly when major females abandon nests for upwards of two to three weeks prior to incubation.<ref name=":8" /><ref>{{cite journal |last1=Wilson |first1=H.R. |last2=Eldred |first2=A.R. |last3=Wilcox |first3=C.J. |title=Storage Time and Ostrich Egg Hatchability |journal=Journal of Applied Poultry Research |date=July 1997 |volume=6 |issue=2 |pages=216–220 |doi=10.1093/japr/6.2.216 |doi-access=free }}</ref> A 2008 study found the salient white egg coloration to be an evolutionary trade-off favoring a reduced risk of eggs overheating and occurrence of embryo mortality over increased predation during these periods of exposure.<ref name=":8" />[[File:Ostrich eggs in a nest at an ostrich farm, South Pasadena, ca.1900 (CHS-823).jpg|thumb|Example of an ostrich nest|alt=]] |
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=== Food and feeding === |
=== Food and feeding === |
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Like other ''Struthio camelus'' subspecies, Masai ostriches are almost entirely herbivorous.<ref name=":1" /><ref>{{ |
Like other ''Struthio camelus'' subspecies, Masai ostriches are almost entirely herbivorous.<ref name=":1" /><ref>{{cite journal |last1=Fritz |first1=Julia |last2=Hammer |first2=Sven |last3=Hebel |first3=Christiana |last4=Arif |first4=Abdi |last5=Michalke |first5=Bernhard |last6=Dittmann |first6=Marie T. |last7=Müller |first7=Dennis W.H. |last8=Clauss |first8=Marcus |title=Retention of solutes and different-sized particles in the digestive tract of the ostrich (Struthio camelus massaicus), and a comparison with mammals and reptiles |journal=Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology |date=September 2012 |volume=163 |issue=1 |pages=56–65 |doi=10.1016/j.cbpa.2012.05.184 |pmid=22609929 }}</ref> Their diet consists mainly of grasses, bushes, herbs, succulents, and leaves. Occasionally they will consume flowers, fruits, seeds, and animal protein (e.g. lizards, insects, etc.), but to a lesser extent.<ref name=":1" /><ref name=":6" /> |
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=== Predators === |
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Masai ostriches are not the main prey items for key carnivores.<ref>Okello, Moses Makonjio, et al. "Population Status and trend of the Maasai ostrich in the mid-Kenya—Tanzania borderland." Natural Resources 7.10 (2016): 558.</ref> Only lions are the central predator of adults in most areas, but many species prey on ostrich eggs including [[jackal]]s, [[hyaena]]s, [[lion]]s, and other [[Egyptian vulture|avian species]].<ref name=":1" /><ref name=":2" /> Egg predation poses the greatest threat to the reproductive success of wild ostrich populations. Documented instances have attributed 90% of a single flock's chick mortality to be caused purely by predation.<ref name=":5" /> |
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== Relationship to humans == |
== Relationship to humans == |
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Alongside predation, human activity has been shown to have a negative impact on the success of wild Masai ostrich communities.<ref name=":1" /><ref name=":9">{{ |
Alongside predation, human activity has been shown to have a negative impact on the success of wild Masai ostrich communities.<ref name=":1" /><ref name=":9">{{cite journal |last1=Thiollay |first1=Jean-Marc |title=Severe decline of large birds in the Northern Sahel of West Africa: a long-term assessment |journal=Bird Conservation International |date=December 2006 |volume=16 |issue=4 |pages=353–365 |doi=10.1017/S0959270906000487 |doi-access=free }}</ref> Anthropogenic-induced ostrich population decline is believed to be attributed to rapid human expansion within Sub-Saharan Africa, resulting in reduced resources and territory availability.<ref name=":9" /> Collection of ostrich eggs by both locals and tourists within protected areas has also poses a substantial negative impact on their population success.<ref name=":1" /><ref name=":10">{{cite journal |last1=Magige |first1=Flora John |last2=Holmern |first2=Tomas |last3=Stokke |first3=Sigbjørn |last4=Mlingwa |first4=Charles |last5=Røskaft |first5=Eivin |title=Does illegal hunting affect density and behaviour of African grassland birds? A case study on ostrich (Struthio camelus) |journal=Biodiversity and Conservation |date=May 2009 |volume=18 |issue=5 |pages=1361–1373 |doi=10.1007/s10531-008-9481-6 |s2cid=3149903 }}</ref> Interestingly, a 2009 study found that illegal hunting of ostrich meat did not significantly affect Masai ostrich population density within the Serengeti National Park.<ref name=":10" /> |
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During the 1990s, worldwide domestication and breeding of the Masai ostrich rose in popularity.<ref>Horbañczuk |
During the 1990s, worldwide domestication and breeding of the Masai ostrich rose in popularity.<ref>{{cite journal |last1=Horbañczuk |first1=J. |last2=Sales |first2=J. |year=2001 |title=Egg production of Red and Blue Neck ostriches under European farming conditions |journal=Archiv für Geflügelkunde |volume=65 |issue=6 |pages=281–283 |url=https://www.european-poultry-science.com/artikel.dll/2001-65-281-283_NDk2MDQwMQ.PDF }}</ref> The primary products of ostrich farming are meat and leather.<ref name="ReferenceA"/> ''S. c. massaicus'' serves as an ideal alternative meat source due to its large size and notably tender meat.<ref name=":11">{{cite journal |last1=Velotto |first1=S. |last2=Varricchio |first2=E. |last3=Vitale |first3=C. |last4=Crasto |first4=A. |title=Post-mortem analysis in three muscles of red neck ostrich (Struthio camelus massaicus). |journal=Israel Journal of Veterinary Medicine |date=2010 |volume=65 |issue=4 |pages=142–94 |url=http://www.ijvm.org.il/sites/default/files/post_mortem_of_red_neck_ostrich.pdf |s2cid=35805650 }}</ref> The greater occurrence of [[Skeletal muscle|type I compared to type II fibres]] as well as high concentrations of [[calpain]]/[[calpastatin]] systems in numerous muscle groups in this subspecies are believed to attribute to this tenderness.<ref name=":11" /> |
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Ostrich eggs and feathers have been harvested for ornamental purposes throughout history, but are frequently utilized today by the [[Maasai people|Maasai]] as source of food and as a vessel for liquids.<ref name=":6" /><ref name=":10" /><ref |
Ostrich eggs and feathers have been harvested for ornamental purposes throughout history, but are frequently utilized today by the [[Maasai people|Maasai]] as source of food and as a vessel for liquids.<ref name=":6" /><ref name=":10" /><ref name=IUCN/> |
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== Status == |
== Status == |
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Though ''Struthio camelus'' is listed as a species of “least concern” under the [[IUCN Red List|IUCN red list]], wild ostrich populations are acknowledged to be in decline.<ref name=":1" /><ref name=":9" /> |
Though ''Struthio camelus'' is listed as a species of “least concern” under the [[IUCN Red List|IUCN red list]], wild ostrich populations are acknowledged to be in decline.<ref name=":1" /><ref name=":9" /> |
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==References== |
==References== |
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{{Commons category|Struthio camelus massaicus}} |
{{Commons category|Struthio camelus massaicus}} |
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[[Category:Birds described in 1898]] |
[[Category:Birds described in 1898]] |
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[[Category:Taxa named by Oscar Neumann]] |
[[Category:Taxa named by Oscar Neumann]] |
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[[Category:Ostriches]] |
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Latest revision as of 13:16, 21 September 2024
| Masai ostrich | |||
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| Male | |||
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| Female | |||
Scientific classification 
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| Domain: | Eukaryota | ||
| Kingdom: | Animalia | ||
| Phylum: | Chordata | ||
| Class: | Aves | ||
| Infraclass: | Palaeognathae | ||
| Order: | Struthioniformes | ||
| Family: | Struthionidae | ||
| Genus: | Struthio | ||
| Species: | |||
| Subspecies: | S. c. massaicus
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| Trinomial name | |||
| Struthio camelus massaicus | |||
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Struthio camelus distribution map
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The Masai ostrich (Struthio camelus massaicus), also known as the East African ostrich is a red-necked subspecies variety of the common ostrich and is endemic to East Africa.[2][3] It is one of the largest birds in the world, second only to its sister subspecies Struthio camelus camelus.[4] Today it is farmed for eggs, meat, and feathers.[5][6]
Taxonomy
[edit]Subspecies
[edit]The Masai ostrich is one of the three extant subspecies of ostrich currently inhabiting Africa, including the nominative ostrich (S. c. camelus) found across northern Africa and the South African ostrich (S. c. australis). It is considered one of the two red-necked forms of ostrich, along with S. c. camelus, as opposed to the two blue-necked forms (S. c. australis and S. c. molybdyphanes).[3]
Comparative restriction-enzyme analysis of mitochondrial DNA (mtDNA) found the Masai ostrich, though genetically distinct, is most closely related to S. c. australis, despite their geographical separation, and least genetically related to S. c. molybdophanes, despite habitat overlap.[7][8] Explanations for these counterintuitive findings are that while the Brachystegia or “miombo” woodlands currently serves as a zoogeographic barrier separating northern and southern ostrich populations, it is theorized that this barrier was not as dense and effective throughout evolutionary time and once allowed for brief periods of intraspecific breeding between S. c. massaicus and S. c. australis populations.[7] Conversely, the genetic divergence observed between S. c. massaicus and S. c. molybdophanes, albeit a lack of any zoogeographic barrier, is thought to be due to the ecological differences in behavioral and reproductive cues between these populations. These differences were substantial enough to prevent intraspecific breeding throughout time.[7][8] These same studies found S. c. massaicus to significantly differ genetically from S. c. camelus subspecies.[7][8]
Although the now extinct subspecies S. c. syriacus was determined to also be a red-necked form of ostrich based on historical evidence, similar analysis of mtDNA found the Masai ostrich to not be as close of a relative to S. c. syriacus compared to S. c. camelus.[9]
Description
[edit]Anatomy
[edit]Adult males are 2.1–2.7 m in height and can weigh up to 145 kg; females are typically slightly smaller in size.[5] They have large eyes (50 mm across), long eyelashes, and exceptional vision.[10] Their heads are relatively small compared to their body and are covered in degenerated feathers that give the upper two-thirds of their elongated neck an almost naked appearance.[11] The skin of the neck and thighs of male Masai ostriches is bare and pink in color, which intensifies to an almost reddish hue during mating season.[4]
Their large size prevents the capability of flight, but this is compensated by their exceptionally long and muscular legs, which allow for maximum running speeds of up to 60–70 km/h.[12]
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Plumage
[edit]The feathers of the Masai ostrich lack barbs, which gives them a soft, downy appearance.[4] Similar to other ostrich subspecies, they possess approximately 50–60 tail feathers, 16 primaries, 4 alular, and 20–23 secondary feathers. The wing and tail feathers have evolved to serve as decorative plumes for courtship display rather than flight.[11]
For males, the majority of the body is covered in black feathers. White feathers appear along the tips of the wings, tail, and form a small ring partway up the neck that separates the black body feathers from bare neck skin. The white tail feathers are often discolored from dirt and appear reddish-brown.[4]
Females tend to be smaller than males and also possess bare skin on both the neck and legs, though their skin color appears more beige than pink. Adult females body feathers are a uniformly-distributed, monochromatic color scheme of brown.[4]
Reproductive/Excretory organs
[edit]
Unlike most avian species, male ostriches have a retractable penis that averages 20 cm in length and everts during defecation, urination, and copulation.[4][11] The ostrich is the only bird to void urine separate from defecation due to the muscular sphincter-like folds located within the cloaca.[11][13]
Environmental adaptations
[edit]Several physiological adaptations have evolved to allow the Masai ostrich to live in the extreme arid conditions of Sub-Saharan Africa. Their feathers have specialized to work as efficient insulators for proper thermoregulation during both hot and cold climates.[14] Increased aldosterone release and use of mucus in place of water for excretion of uric acid promotes water retention in arid environments. Masai ostriches also possess salt-excreting nasal glands which allow for consumption of salt water from saline and soda lakes when necessary.[15]
Distribution and habitat
[edit]Wild Masai ostriches are located across Uganda, Kenya and Tanzania.[3] Denser populations are often found in the semi-arid, open grassy plains of the African savanna.[4] Despite this preference, they have been known to also inhabit desert, dense brush, and steep rocky mountain environments.[11]
Behavior and ecology
[edit]Breeding
[edit]
Masai ostrich breeding season begins around May or June. During this time, the pink hue on male Masai ostriches neck and leg skin intensifies as a form of mating display. Mature males begin to establish territories that are about 2–3 km2 in area and aggressively defend their domain against other breeding males. They will also construct scrape nests in prior to the arrival of breeding females.[10]
In July, adult female ostriches begin establishing breeding zones that span around 13 km2. These breeding zones overlap with 5–7 male territories, in which males attempt to mate with any adult females that pass through his territory.[10]
Communal nesting
[edit]
Similar to other ostrich subspecies, the Masai ostrich nests in groups and engages in crѐching behavior where a single (major) female incubates the eggs of several other (minor) females within a single nest.[10][16] Only 1 out of 3 hens will become a major female, the remaining hens are considered minor females and will not incubate their own eggs.[10] A nest is initiated when a single major female mates with a territorial male who has already prepared a nesting site and performed a complex mating display.[4][10][11] After she lays the initial clutch, both her and the territorial male assume primary care of the eggs.[10] The major female lays on average 2 eggs per day and will spend a subsequent 15–90 minutes incubating, then will periodically leave the nest unattended to allow minor females to copulate with the territorial male and lay eggs in the nest. The male will often spend more time incubating the nest than the major female.[10][4] An upwards of 18 different minor females will lay eggs in a single major females nest, resulting in an excess of eggs. Since both male and female Masai ostriches are only able to incubate 20–21 eggs at a time, so the major female will eject excess eggs. A reproductive advantage observed in major females is that they are able to recognize their own eggs and will eject minor female eggs in favor of theirs as a necessary way to reduce nest overcrowding.[17]
Eggs
[edit]Masai ostrich eggs are large (grapefruit-sized) and white in color.[10][18] They measure 14–16 cm and weigh between 1.0 and 1.6 kg.[19] Egg hatching occurs during October and November, when eastern Africa experiences brief periods of rainfall that generates edible plants that are the Masai ostriches primary food source.[10] Hatchlings are about the size of a domestic chicken hen and are physically precocious, but still require parental care.[10][11]
The conspicuous size and color of the Masai ostrich eggs makes them an easy target for predation, particularly when major females abandon nests for upwards of two to three weeks prior to incubation.[18][20] A 2008 study found the salient white egg coloration to be an evolutionary trade-off favoring a reduced risk of eggs overheating and occurrence of embryo mortality over increased predation during these periods of exposure.[18]
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Food and feeding
[edit]Like other Struthio camelus subspecies, Masai ostriches are almost entirely herbivorous.[4][21] Their diet consists mainly of grasses, bushes, herbs, succulents, and leaves. Occasionally they will consume flowers, fruits, seeds, and animal protein (e.g. lizards, insects, etc.), but to a lesser extent.[4][11]
Predators
[edit]Masai ostriches are not the main prey items for key carnivores.[22] Only lions are the central predator of adults in most areas, but many species prey on ostrich eggs including jackals, hyaenas, lions, and other avian species.[4][5] Egg predation poses the greatest threat to the reproductive success of wild ostrich populations. Documented instances have attributed 90% of a single flock's chick mortality to be caused purely by predation.[10]
Relationship to humans
[edit]Alongside predation, human activity has been shown to have a negative impact on the success of wild Masai ostrich communities.[4][23] Anthropogenic-induced ostrich population decline is believed to be attributed to rapid human expansion within Sub-Saharan Africa, resulting in reduced resources and territory availability.[23] Collection of ostrich eggs by both locals and tourists within protected areas has also poses a substantial negative impact on their population success.[4][24] Interestingly, a 2009 study found that illegal hunting of ostrich meat did not significantly affect Masai ostrich population density within the Serengeti National Park.[24]
During the 1990s, worldwide domestication and breeding of the Masai ostrich rose in popularity.[25] The primary products of ostrich farming are meat and leather.[6] S. c. massaicus serves as an ideal alternative meat source due to its large size and notably tender meat.[26] The greater occurrence of type I compared to type II fibres as well as high concentrations of calpain/calpastatin systems in numerous muscle groups in this subspecies are believed to attribute to this tenderness.[26]
Ostrich eggs and feathers have been harvested for ornamental purposes throughout history, but are frequently utilized today by the Maasai as source of food and as a vessel for liquids.[11][24][1]
Status
[edit]Though Struthio camelus is listed as a species of “least concern” under the IUCN red list, wild ostrich populations are acknowledged to be in decline.[4][23]
References
[edit]
Wikimedia Commons has media related to Struthio camelus massaicus.
Wikispecies has information related to Struthio camelus massaicus.
- ^ a b BirdLife International (2018). "Struthio camelus massaicus". IUCN Red List of Threatened Species. 2018. doi:10.2305/IUCN.UK.2018-2.RLTS.T45020636A132189458.en.
- ^ "Struthio camelus massaicus (African Ostrich (North African)) - Avibase". avibase.bsc-eoc.org. Retrieved 2019-12-05.
- ^ a b c Seddon, Philip J.; Soorae, Pritpal S. (February 1999). "Guidelines for Subspecific Substitutions in Wildlife Restoration Projects". Conservation Biology. 13 (1): 177–184. doi:10.1046/j.1523-1739.1999.97414.x. S2CID 84578693.
- ^ a b c d e f g h i j k l m n o Bertram, Brian C. R. (2014). The Ostrich Communal Nesting System. Princeton: Princeton University Press. ISBN 978-1-4008-6314-3. OCLC 884012871.[page needed]
- ^ a b c Magige, Flora John (2008). The ecology and behaviour of the Masai Ostrich (Struthio camelus massaicus) in the Serengeti Ecosystem, Tanzania (Thesis). hdl:11250/244464.
- ^ a b McKeegan, D.E.F.; Deeming, D.C. (January 1997). "Effects of gender and group size on the time-activity budgets of adult breeding ostriches (Struthio camelus) in a farming environment". Applied Animal Behaviour Science. 51 (1–2): 159–177. doi:10.1016/S0168-1591(96)01096-9.
- ^ a b c d Freitag, Stefanie; Robinson, Terence J. (1993). "Phylogeographic Patterns in Mitochondrial DNA of the Ostrich (Struthio camelus)". The Auk. 110 (3): 614–622. doi:10.2307/4088425. JSTOR 4088425.
- ^ a b c Miller, Joshua M.; Hallager, Sara; Monfort, Steven L.; Newby, John; Bishop, Kelley; Tidmus, Scott A.; Black, Peter; Houston, Bill; Matthee, Conrad A.; Fleischer, Robert C. (April 2011). "Phylogeographic analysis of nuclear and mtDNA supports subspecies designations in the ostrich (Struthio camelus)". Conservation Genetics. 12 (2): 423–431. doi:10.1007/s10592-010-0149-x. S2CID 28575743.
- ^ Robinson, Terence J.; Matthee, Conrad A. (August 1999). "Molecular genetic relationships of the extinct ostrich, Struthio camelus syriacus: consequences for ostrich introductions into Saudi Arabia". Animal Conservation. 2 (3): 165–171. doi:10.1111/j.1469-1795.1999.tb00062.x. S2CID 85959044.
- ^ a b c d e f g h i j k l Hurxthal, Lewis M. (1986). "Our gang, ostrich style". Natural History. 95: 34–41, 94.
- ^ a b c d e f g h i Grzimek, Bernhard (1972–75). Grzimek's Animal life encyclopedia. New York: Van Nostrand Reinhold Co. ISBN 0-442-78478-3. OCLC 425737.[page needed]
- ^ Brown, Leslie; Urban, Emil K.; Newman, Kenneth (1982). The birds of Africa. London: Academic Press. ISBN 0-12-137301-0. OCLC 8982298.[page needed]
- ^ Warui, C. N.; Macharia, R. G.; Mwangi, D. K.; Macheru, P. W.; Moilo, J. (1998). "Observations on the morphology of the cloacal region of the African ostrich (Struthio camelus massaicus)". The Kenya Veterinarian. 23: 53–55. hdl:11295/65982.
- ^ Louw, Gideon N., Belonje, Peter C. & Coetzee Hendrik J. (1 January 1972). "Renal function, respiration, heart rate and thermoregulation in the ostrich (Struthio camelus)". Scientific Papers of the Namib Desert Research Station. 1972 (42): 43–54. hdl:10520/AJA0000008_220.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Cloudsley-Thompson, J. L.; Mohamed, El Rasid Musa (December 1967). "Water Economy of the Ostrich". Nature. 216 (5119): 1040. Bibcode:1967Natur.216.1040C. doi:10.1038/2161040a0. S2CID 4278385.
- ^ Kimwele, C. N.; Graves, J. A. (19 December 2002). "A molecular genetic analysis of the communal nesting of the ostrich (Struthio camelus)". Molecular Ecology. 12 (1): 229–236. doi:10.1046/j.1365-294x.2003.01727.x. PMID 12492891. S2CID 32020136.
- ^ Bertram, Brian C. R. (May 1979). "Ostriches recognise their own eggs and discard others". Nature. 279 (5710): 233–234. Bibcode:1979Natur.279..233B. doi:10.1038/279233a0. PMID 440431. S2CID 4236729.
- ^ a b c Magige, Flora John; Moe, Børge; Røskaft, Eivin (July 2008). "The white colour of the Ostrich (Struthio camelus) egg is a trade-off between predation and overheating". Journal of Ornithology. 149 (3): 323–328. doi:10.1007/s10336-008-0273-2. S2CID 25321892.
- ^ Muwazi, R. T.; Baranga, Jonathan; Kayanja, Frederik I. B.; Schliemann, Harald (October 1982). "The oviduct of the ostrichStruthio camelus massaicus". Journal für Ornithologie. 123 (4): 425–433. doi:10.1007/BF01643275. S2CID 42620338.
- ^ Wilson, H.R.; Eldred, A.R.; Wilcox, C.J. (July 1997). "Storage Time and Ostrich Egg Hatchability". Journal of Applied Poultry Research. 6 (2): 216–220. doi:10.1093/japr/6.2.216.
- ^ Fritz, Julia; Hammer, Sven; Hebel, Christiana; Arif, Abdi; Michalke, Bernhard; Dittmann, Marie T.; Müller, Dennis W.H.; Clauss, Marcus (September 2012). "Retention of solutes and different-sized particles in the digestive tract of the ostrich (Struthio camelus massaicus), and a comparison with mammals and reptiles". Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology. 163 (1): 56–65. doi:10.1016/j.cbpa.2012.05.184. PMID 22609929.
- ^ Okello, Moses Makonjio, et al. "Population Status and trend of the Maasai ostrich in the mid-Kenya—Tanzania borderland." Natural Resources 7.10 (2016): 558.
- ^ a b c Thiollay, Jean-Marc (December 2006). "Severe decline of large birds in the Northern Sahel of West Africa: a long-term assessment". Bird Conservation International. 16 (4): 353–365. doi:10.1017/S0959270906000487.
- ^ a b c Magige, Flora John; Holmern, Tomas; Stokke, Sigbjørn; Mlingwa, Charles; Røskaft, Eivin (May 2009). "Does illegal hunting affect density and behaviour of African grassland birds? A case study on ostrich (Struthio camelus)". Biodiversity and Conservation. 18 (5): 1361–1373. doi:10.1007/s10531-008-9481-6. S2CID 3149903.
- ^ Horbañczuk, J.; Sales, J. (2001). "Egg production of Red and Blue Neck ostriches under European farming conditions" (PDF). Archiv für Geflügelkunde. 65 (6): 281–283.
- ^ a b Velotto, S.; Varricchio, E.; Vitale, C.; Crasto, A. (2010). "Post-mortem analysis in three muscles of red neck ostrich (Struthio camelus massaicus)" (PDF). Israel Journal of Veterinary Medicine. 65 (4): 142–94. S2CID 35805650.