The ostrich (Struthio camelus) as a quasi-ungulate, part 2: proportional sizes of organs in ostrich-size, yearling juveniles of the eastern white-bearded wildebeest (Connochaetes albojubatus) near Nairobi, Kenya

The following illustrate juveniles of the eastern white-bearded wildebeest (Connochaetes albojubatus, https://www.inaturalist.org/observations?taxon_id=525438) at an ontogenetic stage corresponding in body mass approximately to adults of the coexisting Maasai ostrich (Struthio camelus massaicus, https://www.inaturalist.org/observations?taxon_id=322201).

Please note that the body mass has just exceeded half of maternal body mass, but the horns - albeit much longer than the ears or mane - are still simple spikes directed dorsally.

https://www.inaturalist.org/observations/7898982

https://www.inaturalist.org/observations/110103601

https://www.inaturalist.org/observations/124808683

https://www.inaturalist.org/observations/102212589

https://www.inaturalist.org/observations/189131122

https://www.inaturalist.org/observations/191952637

Scroll in https://fossilrim.org/animals/common-wildebeest/

Scroll in https://www.zootierliste.de/en/?klasse=1&ordnung=121&familie=12115&art=1160826

Compare with

• younger than the study category, at <1 year old: https://www.inaturalist.org/observations/131034142
• older than the study category, with the horns acquiring a curve at the base: https://www.inaturalist.org/observations/181075800

Sample size large, of both sexes

Location:
Wildlife Ranching and Research, later Swara Plains Conservancy, and now incorporated into Nairobi National Park

Time:
1986-1989

The following are mean values of percentage of body mass, followed by the actual masses in parentheses.

Body mass 111 kg

Carcass mass = 54.22% (60.184 kg)

Skin = 7.92% (8.788 kg)

Feet = 2.93% (3.253 kg)

Head = 7.29% (8.088 kg)

Brain = 0.267% (0.296 kg)

Eyeballs = 0.0438% (2 X 0.0243 kg)

Tongue = 0.23% (0.259 kg)

Masseter muscle = 0.266% (2 X 0.148 kg)

Heart = 0.726% (0.806 kg)

Lungs = 1.55% (1.726 kg)

Spleen = 0.35% (0.392 kg)

Liver = 1.28% (1.422 kg)

Kidneys = 0.265% (2 X 0.147 kg)

Rumen = 1.67% (1.859 kg)

Reticulum = 0.275% (0.305 kg)

Omasum = 0.43% (0.480 kg)

Abomasum = 0.34% (0.375 kg)

Total intestines (full?) = 4.83% (5.363 kg)

Total stomach = 2.72% (3.019 kg)

DISCUSSION

Elsewhere in this series of Posts, I compare the Maasai ostrich with a coexisting alcelaphin ruminant - namely Alcelaphus cokii (https://www.inaturalist.org/observations?taxon_id=132649) - of similar adult body mass to the bird.

The values presented here - except for brain and skin - exceed those of adults of A. cokii, of similar body mass, in their overall resemblance to the Maasai ostrich.

The ostrich is constituted in some ways like juveniles of a ruminant, with big organs and feet (suggesting emphasis on mobility and foraging and rapid metabolism).

Posted on May 18, 2024 03:19 PM by milewski