Ostrich egg

Last updated September 01, 2024

The egg of the ostrich (genus Struthio) is the largest of any living bird (being exceeded in size by those of the extinct elephant bird genus Aepyornis ). The shell has a long history of use by humans as a container and for decorative artwork, including beads. The eggs are not commonly eaten.

Biology

The female common ostrich lays her fertilized eggs in a single communal nest, a simple pit, 30 to 60 cm (12–24 in) deep and 3 m (9.8 ft) wide,^[1] scraped in the ground by the male. The dominant female lays her eggs first, and when it is time to cover them for incubation she discards extra eggs from the weaker females, leaving about 20 in most cases.^[2] A female common ostrich can distinguish her own eggs from the others in a communal nest.^[3] Ostrich eggs are the largest of all eggs,^[4] though they are actually the smallest eggs relative to the size of the adult bird — on average they are 15 cm (5.9 in) long, 13 cm (5.1 in) wide, and weigh 1.4 kilograms (3.1 lb), over 20 times the weight of a chicken's egg and only 1 to 4% the size of the female.^[5] They are glossy cream-colored, with thick shells marked by small pits.^[6]

The eggs are incubated by the females by day and by the males by night. This uses the coloration of the two sexes to escape detection of the nest, as the drab female blends in with the sand, while the black male is nearly undetectable in the night.^[6] The incubation period is 35 to 45 days, which is rather short compared to other ratites. This is believed to be the case due to the high rate of predation.^[5] Typically, the male defends the hatchlings and teaches them to feed, although males and females cooperate in rearing chicks. Fewer than 10% of nests survive the 9 week period of laying and incubation, and of the surviving chicks, only 15% of those survive to 1 year of age.^[7]

A possible origin for the myth that ostriches bury their heads in sand to avoid danger lies with the fact that ostriches keep their eggs in holes in the sand instead of nests, and must rotate them using their beaks during incubation; digging the hole, placing the eggs, and rotating them might each be mistaken for an attempt to bury their heads in the sand.^[8]

Human uses

In Thebes, Egypt, the tomb of Haremhab, dating to approximately 1420 BC, shows a depiction of a man carrying bowls of ostrich eggs and other large eggs, presumably those of the pelican, as offerings.^[9]

Ostrich eggshells were used as containers in North Africa as early as the fourth millennium BC and in the Royal Cemetery at Ur from the third millennium. From the first millennium in the ancient Punic civilization, there are many examples of ostrich eggs decorated with painted geometric designs for use as cups and bowls. These have been found in Carthage, Sardinia, Sicily, the Iberian Peninsula and Ibiza. The tradition of using ostrich eggs as containers (sometimes decorated) continues to the present among the San people.^[10]

In the Middle Ages, ostrich eggs from Ethiopia were exported through the port of Bāḍiʿ on the Red Sea.^[11] During the Renaissance in Europe (15th–16th centuries AD), ostrich eggs were mounted in silver as goblets for display in cabinets of curiosities.^[10] Decorated eggs continue to be widely displayed in Eastern Orthodox churches, although their symbolism is disputed. They may symbolize the Virgin Birth, since according to Job 39:13–17 the ostrich lays its eggs in the sand and forgets, so they are hatched by the sun alone. This significance may lie behind the egg suspended above the Virgin Mary in Piero della Francesca's Brera Madonna painting.^[12]

In 2020, studies of decorated ostrich eggs in the British Museum showed that the methods by which they had been sourced, produced and traded were more complicated than had previously been imagined.^[13] Isotope analysis showed that eggs from the same archaeological site had originated in different places. The studies suggested that, rather than the eggs having been laid by captive birds, almost all had most likely been collected in the wild; a potentially hazardous undertaking.^[14]

Today, ostrich eggs are a special luxury food.^[15]

Gallery

Mycenaean ostrich egg rhyton
Decorated Punic egg
Ostrich sitting on eggs, from the Book of Animals of al-Jahiz
15th-century reliquary
Brera Madonna by Piero della Francesca (c. 1472)
Carved ostrich egg (17th century)
A San man drinking from an ostrich egg
In a frying pan
Comparison of an ostrich egg (centre) with that of the elephant bird Aepyornis (top left), a chicken (bottom left) and a moa (right)

Related Research Articles

The common ostrich, or simply ostrich, is a species of flightless bird native to certain large areas of Africa. It is one of two extant species of ostriches, the only living members of the genus Struthio in the ratite order of birds. The other is the Somali ostrich, which was recognized as a distinct species by BirdLife International in 2014 having been previously considered a distinctive subspecies of ostrich.

Rheas, also known as ñandus or South American ostrich, are moderately sized South American ratites of the order Rheiformes. They are distantly related to the African ostriches and Australia's emu, with rheas placing just behind the emu in height and overall size.

The emu is a species of flightless bird endemic to Australia, where it is the tallest native bird. It is the only extant member of the genus Dromaius and the third-tallest living bird after its African ratite relatives, the common ostrich and Somali ostrich. The emu's native ranges cover most of the Australian mainland. The Tasmanian, Kangaroo Island and King Island subspecies became extinct after the European settlement of Australia in 1788.

A ratite is any of a group of mostly flightless birds within the infraclass Palaeognathae. They are mostly large, long-necked, and long-legged, the exception being the kiwi, which is also the only nocturnal extant ratite.

The cotingas are a large family, Cotingidae, of suboscine passerine birds found in Central America and tropical South America. Cotingas are birds of forests or forest edges, that are primary frugivorous. They all have broad bills with hooked tips, rounded wings, and strong legs. They range in size from 12–13 cm (4.7–5.1 in) of the fiery-throated fruiteater up to 48–51 cm (19–20 in) of the Amazonian umbrellabird.

Elephant birds are extinct flightless birds belonging to the order Aepyornithiformes that were native to the island of Madagascar. They are thought to have become extinct around 1000 AD, likely as a result of human activity. Elephant birds comprised three species, one in the genus Mullerornis, and two in Aepyornis.Aepyornis maximus is possibly the largest bird to have ever lived, with their eggs being the largest known for any amniote. Elephant birds are palaeognaths, and their closest living relatives are kiwi, suggesting that ratites did not diversify by vicariance during the breakup of Gondwana but instead convergently evolved flightlessness from ancestors that dispersed more recently by flying.

Egg incubation is the process by which an egg, of oviparous (egg-laying) animals, develops an embryo within the egg, after the egg's formation and ovipositional release. Egg incubation is done under favorable environmental conditions, possibly by brooding and hatching the egg.

The little tinamou is a species of tinamou. It is found in Central and South America, as well as on the Caribbean island of Trinidad.

Flightless birds have, through evolution, lost the ability to fly. There are over 60 extant species, including the well-known ratites and penguins. The smallest flightless bird is the Inaccessible Island rail. The largest flightless bird, which is also the largest living bird in general, is the common ostrich.

Ostriches are large flightless birds. Two living species are recognised, the common ostrich, native to large areas of sub-Saharan Africa, and the Somali ostrich, native to the Horn of Africa.

The red-winged tinamou is a medium-sized ground-living bird from central and eastern South America. Other common names for the species include perdiz grande, rufous tinamou, and ynambu.

The Okarito kiwi, also known as the rowi or Okarito brown kiwi, is a member of the kiwi family Apterygidae, described as new to science in 2003. The species is part of the brown kiwi complex, and is morphologically very similar to other members of that complex. It is found in a restricted area of the Ōkārito forest on the West Coast of New Zealand's South Island, and has a population of only about 600 birds.

Darwin's rhea or the lesser rhea is a large flightless bird, the smaller of the two extant species of rheas. It is found in the Altiplano and Patagonia in South America.

The greater rhea is a species of flightless bird native to eastern South America. Other names for the greater rhea include the grey, common, or American rhea; ema (Portuguese); or ñandú. One of two species in the genus Rhea, in the family Rheidae, it inhabits a variety of open areas, such as grasslands, savanna or grassy wetlands. Weighing 20–27 kilograms (44–60 lb), the greater rhea is the largest native bird in the Americas. In the wild, the greater rhea has a life expectancy of 10.5 years. It is also notable for its reproductive habits, and for the fact that a population has established itself in Northern Germany in recent years. The species is listed as Near Threatened by the IUCN.

The northern cassowary, also known as the one-wattled cassowary, single-wattled cassowary, or golden-necked cassowary, is a large, stocky flightless bird of northern New Guinea. It is one of the three living species of cassowary, alongside the dwarf cassowary and the southern cassowary. It is a member of the superorder Paleognathae.

$<span class="mw-page-title-main">Palaeognathae</span> Infraclass of birds$

Palaeognathae is an infraclass of birds, called paleognaths or palaeognaths, within the class Aves of the clade Archosauria. It is one of the two extant infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae contains five extant branches of flightless lineages, termed ratites, and one flying lineage, the Neotropic tinamous. There are 47 species of tinamous, five of kiwis (Apteryx), three of cassowaries (Casuarius), one of emus (Dromaius), two of rheas (Rhea) and two of ostriches (Struthio). Recent research has indicated that paleognaths are monophyletic but the traditional taxonomic split between flightless and flighted forms is incorrect; tinamous are within the ratite radiation, meaning flightlessness arose independently multiple times via parallel evolution.

Aepyornis is an extinct genus of elephant bird formerly endemic to Madagascar. The genus had two species, the smaller A. hildebrandti and the larger A. maximus, which is possibly the largest bird ever to have lived. Its closest living relative is the New Zealand kiwi. They became extinct sometime around 1000 AD, probably as a result of human activity.

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References

↑ Harrison, C.; Greensmith, A. (1993). Bunting, E. (ed.). Birds of the World. New York, NY: Dorling Kindersley. p. 39. ISBN 978-1-56458-295-9.
↑ Davies, S.J.J.F. (2003). "Birds I Tinamous and Ratites to Hoatzins". In Hutchins, Michael (ed.). Grzimek's Animal Life Encyclopedia. Vol. 8 (2nd ed.). Farmington Hills, MI: Gale Group. pp. 99–101. ISBN 978-0-7876-5784-0.
↑ Bertram, B.C.R. (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.
↑ Hyde, Kenneth (2004). Zoology: An Inside View of Animals (3rd ed.). Dubuque, IA: Kendall Hunt Publishing. p. 475. ISBN 978-0-7575-0170-8.
1 2 Perrins, Christopher (1987) [1979]. Harrison, C.J.O. (ed.). Birds: Their Lifes, Their Ways, Their World. Reader's Digest Association, Inc. pp. 168–170. ISBN 978-0-89577-065-3.
1 2 Nell, Leon (2003). The Garden Route and Little Karoo. Cape Town: Struik Publishers. p. 164. ISBN 978-1-86872-856-5.
↑ Davies, S. J. J. F.; Bertram, B. C. R. (2003). "Ostrich". In Perrins, Christopher (ed.). Firefly Encyclopedia of Birds. Buffalo, NY: Firefly Books, Ltd. pp. 34–37. ISBN 978-1-55297-777-4.
↑ "Do ostriches really bury their heads in the sand?". Science World British Columbia. 11 December 2015. Retrieved 2 January 2017.
↑ Brothwell, Don R.; Patricia Brothwell (1997). Food in Antiquity: A Survey of the Diet of Early Peoples. Johns Hopkins University Press. pp. 54–55. ISBN 978-0-8018-5740-9.
1 2 Gordon Campbell, ed. (2006), "Ostrich eggs", The Grove Encyclopedia of Decorative Arts, Oxford University Press.
↑ Yusuf Fadl Hasan (1967), The Arabs and the Sudan: From the Seventh to the Early Sixteenth Century (Edinburgh University Press), pp. 64–66.
↑ Tom Devonshire Jones; Linda Murray; Peter Murray, eds. (2013), "Ostrich eggs", The Oxford Dictionary of Christian Art and Architecture (2nd ed.), Oxford University Press.
↑ Hodos, Tamar (2020). "The origins of decorated ostrich eggs in the ancient Mediterranean and Middle East". Antiquity. 94 (374): 381–400. doi:10.15184/aqy.2020.14. S2CID 216354574.
↑ Addley, Esther (9 April 2020). "British Museum looks to crack mystery over decorated ostrich eggs". The Guardian . Retrieved 10 April 2020.
↑ Roux, Michel; Martin Brigdale (2006). Eggs. Wiley. p. 8. ISBN 978-0-471-76913-2.

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[Harrison-1] Harrison, C.; Greensmith, A. (1993). Bunting, E. (ed.). Birds of the World. New York, NY: Dorling Kindersley. p. 39. ISBN 978-1-56458-295-9.

[Davies-2] Davies, S.J.J.F. (2003). "Birds I Tinamous and Ratites to Hoatzins". In Hutchins, Michael (ed.). Grzimek's Animal Life Encyclopedia. Vol. 8 (2nd ed.). Farmington Hills, MI: Gale Group. pp. 99–101. ISBN 978-0-7876-5784-0.

[Bertram1979-3] Bertram, B.C.R. (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.

[Hyde-4] Hyde, Kenneth (2004). Zoology: An Inside View of Animals (3rd ed.). Dubuque, IA: Kendall Hunt Publishing. p. 475. ISBN 978-0-7575-0170-8.

[Perrins-5] 1 2 Perrins, Christopher (1987) [1979]. Harrison, C.J.O. (ed.). Birds: Their Lifes, Their Ways, Their World. Reader's Digest Association, Inc. pp. 168–170. ISBN 978-0-89577-065-3.

[Nell_2003-6] 1 2 Nell, Leon (2003). The Garden Route and Little Karoo. Cape Town: Struik Publishers. p. 164. ISBN 978-1-86872-856-5.

[Perrins2-7] Davies, S. J. J. F.; Bertram, B. C. R. (2003). "Ostrich". In Perrins, Christopher (ed.). Firefly Encyclopedia of Birds. Buffalo, NY: Firefly Books, Ltd. pp. 34–37. ISBN 978-1-55297-777-4.

[ScienceWorldHeadSand-8] "Do ostriches really bury their heads in the sand?". Science World British Columbia. 11 December 2015. Retrieved 2 January 2017.

[Brothwell-9] Brothwell, Don R.; Patricia Brothwell (1997). Food in Antiquity: A Survey of the Diet of Early Peoples. Johns Hopkins University Press. pp. 54–55. ISBN 978-0-8018-5740-9.

[GEDA-10] 1 2 Gordon Campbell, ed. (2006), "Ostrich eggs", The Grove Encyclopedia of Decorative Arts, Oxford University Press.

[Hasan-11] Yusuf Fadl Hasan (1967), The Arabs and the Sudan: From the Seventh to the Early Sixteenth Century (Edinburgh University Press), pp. 64–66.

[12] Tom Devonshire Jones; Linda Murray; Peter Murray, eds. (2013), "Ostrich eggs", The Oxford Dictionary of Christian Art and Architecture (2nd ed.), Oxford University Press.

[13] Hodos, Tamar (2020). "The origins of decorated ostrich eggs in the ancient Mediterranean and Middle East". Antiquity. 94 (374): 381–400. doi:10.15184/aqy.2020.14. S2CID 216354574.

[14] Addley, Esther (9 April 2020). "British Museum looks to crack mystery over decorated ostrich eggs". The Guardian . Retrieved 10 April 2020.

[Roux8-15] Roux, Michel; Martin Brigdale (2006). Eggs. Wiley. p. 8. ISBN 978-0-471-76913-2.

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