An extreme contrast in the proportional size of the jaws in large herbivores of grassland: ostrich vs warthogs

One of the remarkable aspects of the guild of large herbivores in Africa is the extreme variation in the proportional size of jaws, among species specialised for eating herbaceous plants.

The extremes are shown by the ostrich (Struthio camelus, https://www.inaturalist.org/taxa/20526-Struthio-camelus) and warthogs (Phacochoerus spp., https://www.inaturalist.org/observations?place_id=any&taxon_id=42121&view=species).

Warthogs are the most specialised of suids, on a diet of grass (https://ielc.libguides.com/sdzg/factsheets/warthog_common/diet#:~:text=Though%20omnivorous%2C%20warthogs%20primarily%20feed,stems%2C%20roots%2C%20and%20seeds. and https://academic.oup.com/jmammal/article/87/5/889/899003?login=false and https://www.sciencedirect.com/science/article/pii/S2351989421002729 and https://www.researchgate.net/publication/274229949_Diet_of_the_Common_Warthog_Phacochoerus_africanus_on_Former_Cattle_Grounds_in_a_Tanzanian_Savanna and https://www.proquest.com/docview/221518412).

For its part, the ostrich is an 'honorary ungulate' in the sense that it, like coexisting gazelles, eats mainly greens (https://www.jstor.org/stable/3809386 and https://www.semanticscholar.org/paper/Food-selection-by-ostrich-in-Southern-Africa-Milton-Dean/8e4442285c589243cdbb3a63f1f7a64890efcc27 and https://www.africabib.org/rec.php?RID=Q00023835 and https://www.projecttopics.com/journals/bibliography/is-the-diet-of-the-ostrich-similar-to-that-of-grants-gazelle/ and http://bioweb.uwlax.edu/bio203/s2012/stauder_abig/nutrition.htm#:~:text=The%20types%20of%20plants%20that,on%20these%20types%20of%20nutrients. and https://www.researchgate.net/publication/293332312_Diet_preferences_of_sub-_species_of_ostrich_Struthio_camelus_camelus_and_Struthio_camelus_molybdophanes_at_Langano_ostrich_farm_Abijata-Shalla_Lakes_National_Park_Ethiopia and http://ejol.ethernet.edu.et/index.php/EJBS/article/view/592).

The notion that the ostrich is omnivorous is one of those ambivalences that has misled generations of naturalists. While it is true that the ostrich has the capacity to eat animals and various other categories of food, its staple diet, wherever it lives in the wild, is foliage.

Warthogs, too, retain a capacity for eating animal matter that exceeds that of most ruminants. Therefore, it turns out that the ostrich is directly comparable with coexisting warthogs in an ecological sense - the great phylogenetic distance between them notwithstanding.

https://upload.wikimedia.org/wikipedia/commons/e/eb/Afrikanischer_Strauss_Portrait.jpg

https://upload.wikimedia.org/wikipedia/commons/7/7c/Ostrich%2C_mouth_open.jpg

https://upload.wikimedia.org/wikipedia/commons/6/62/Avestruz_alta.jpg

https://upload.wikimedia.org/wikipedia/commons/2/2a/Common_Ostrich_%28Struthio_camelus%29_skull_at_the_Royal_Veterinary_College_anatomy_museum.JPG

https://upload.wikimedia.org/wikipedia/commons/f/fb/The_Childrens_Museum_of_Indianapolis_-_Ostrich_skull.jpg

https://www.alamy.com/blue-wildebeest-connochaetes-taurinus-adult-male-drinking-water-with-a-male-south-african-ostrich-struthio-camelus-australis-etosha-np-namibia-image477731239.html

http://skullbase.info/skulls/mammals/common_warthog_-_male.php

https://www.shutterstock.com/image-photo/warthog-skull-lower-jaw-african-mammal-1210031404

https://www.alamy.com/animal-skulls-on-dry-ground-warthog-drought-image234130705.html?imageid=F34B4F5D-0586-4C3E-8EF9-94F4C7DFFCB3&p=556824&pn=1&searchId=7c79c808dbf85cded4ca8dc19bee3051&searchtype=0

https://www.alamy.com/stock-photo-the-lower-jaw-of-a-warthog-phacochoerus-africanus-showing-tusks-and-176913274.html?imageid=7D01B333-9E91-4FEA-97F8-483AE7F7714D&p=620835&pn=1&searchId=7c79c808dbf85cded4ca8dc19bee3051&searchtype=0

https://www.istockphoto.com/photo/female-warthog-in-profile-gm91080096-2954354

https://www.alamy.com/breeding-male-common-ostrich-struthio-camelus-drinking-in-puddle-kgalagadi-transfrontier-park-kalahari-northern-cape-south-africa-image416778708.html