Rainbirder

Desert Warthog (Phacochoerus aethiopicus delamerei)

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"Semper aliquid novi Africam adferre" -a famous quote by the Roman natural philosopher Pliny the Elder is often rendered as "Ex Africa semper aliquid novi" -Always something new out of Africa!

How right he was, Africa is full of surprises!

 

7715571870_f99c320d92_o.jpg

Common Warthog (Phacochoerus africanus) boar; Nairobi NP., Kenya; August 2011. (Slightly pointed, uncurled ears; conical-shaped warts; no swellings under the eye; markedly curved canines; narrow snout disc; darkish mane).

 

 

 

 

The Common Warthog (Phacochoerus africanus) is widely known -even by those who have never visited Africa; however there is a second species of warthog which few have ever heard of.

The Desert Warthog (Phacochoerus aethiopicus) was until recently one of the most poorly known and neglected large non-forest mammals in Africa with almost no information available regarding behavour or ecology.

But surely a warthog is a warthog and the suggestion of a second species is just a manifestation of creative taxonomy; yet on further scrutiny it is apparent that the Desert Warthog is a surprisingly different beast from its common cousin.

Matters have been complicated by the rules of taxonomy -the scientific name of the Desert Warthog is Phacochoerus aethiopicus -implying a range including Ethiopia. Indeed it does occur in Ethiopia but the type specimen was described from the Cape in South Africa. At this time it was thought that all warthogs were of one species. The population in South Africa therefore became Phacochoerus aethiopicus aethiopicus -but unfortunately this subspecies became extinct (1871). Subsequently it became apparent that there had been two species of warthog and as the now extinct " Cape Warthog" was the first taxon to be described it retained the name Phacochoerus aethiopicus and the well-known Common Warthog had to be re-named Phacochoerus africanus.
About 2 million years ago an arid corridor extended from the horn of Africa down to the Cape -habitat occupied by Desert Warthog; but following change in climate and therefore vegetation this corridor closed leaving two disjunct populations of Desert Warthog -one in the Cape and the other in the Horn of Africa. With the extinction of the "Cape Warthog" the species fell into obscurity and it was widely thought that all surviving warthogs were Common Warthogs.

In 1909, Lönnberg a Swedish zoologist noted that two male warthog skulls obtained in Somalia were very different from Common Warthog skulls and also lacked incisors. He created a new species, Phacochoerus delamerei, on the basis of these specimens and noted similarities with P. aethiopicus, though he was not convinced that these two taxa were immediately related to each other. Subsequent research has shown that Lönnberg's warthogs belong to the same species as the Cape Warthog -this population is now known as Desert Warthog (Phacochoerus aethiopicus delamerei).

 

 

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Desert Warthog (Phacochoerus aethiopicus) boar; near the Galana/Sabaki river, Tsavo East, Kenya; July 2012.

 

 

 

The Desert Warthog (Phacocherus aethiopicus delameri) is the surviving relative of the Cape warthog (P. a. aethiopicus) which formerly inhabited Cape Province but became extinct in the late nineteenth century. It is only recently that these two subspecies of Phacocherus aethiopicus have been restored to the status of a species – the Desert Warthog – distinct from the Common Warthog P. africanus. Mitochondrial DNA analysis has recently confirmed that the Common and Desert Warthogs are two different and widely divergent species. DNA studies have further shown that the lineages of Desert and Common Warthogs are very distinct and that the two species diverged about 4.5 million years ago in the early Pliocene.

 

 

 

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Desert Warthog (Phacochoerus aethiopicus) boar; near the Galana/Sabaki river, Tsavo East, Kenya; July 2012.

 

 

 

The skull structure of Desert Warthog is very different from that of the Common Warthog:


1) The skull is slightly smaller, but proportionately shorter and broader.

2) Thickened zygomatic arches: the front part of the zygomatic arch is thickened by internal sinuses and swollen into a spherical hollow knob just in front of the jugal-squamosal suture (in the Common warthog, the zygomatic arch may be robust but it is never quite so thickened and there is no formation of a knob).

3) Enlarged sphenoidal pits: In the Common warthog the skull roof behind the internal nares is marked by two deep and distinct “sphenoidal pits”, not found in any other African suid, while in the Desert species, these pits have expanded enormously, disappearing as distinct entities, so as to contribute to two vaults between the pterygoids, separated by a deep vomerine ridge.

4) Absence of incisors: there is never any trace of upper incisors, even in relatively young individuals, and the lower incisors, even if present, are rudimentary and non-functional, and reduced to 2 pairs maximum (whereas the Common Warthog always has two upper incisors, though these may be lost in very old animals, and usually six functional lower incisors in the adult dentition of normal suine form).

5) The large third molars are very different from those of the Common Warthog in that no roots have been formed by the time all the enamel columns have come into wear, so that the columns are able to continue growing and extend the life of the tooth -a feature which markedly prolongs the life of these molars when dealing with tough fibrous foodstuffs.

All of the above, whilst sounding quite technical do result in a very distinctive and different-looking skull in comparison to Common Warthog.

 

 

 

8600876954_e3ba2678bf_o.jpg

Desert Warthog (Phacochoerus aethiopicus) boar; near the Galana/Sabaki river, Tsavo East, Kenya; July 2012.

 

 

 

There are also external differences between the two species which can be readily recognised in the field.

The Desert Warthog has less flamboyantly curved canines whilst the snout disc is much broader and the mane is paler tending towards blonde. However these features are unreliable as Common Warthogs can be quite variable in appearance.

 

 

 

8600876790_35a3c6811a_o.jpg

Desert Warthog (Phacochoerus aethiopicus) two boars at a small waterhole near the Galana/Sabaki river, Tsavo East, Kenya; July 2012.

 

 

 

There are three consistent and reliable external features which separate the two species of warthog:

 

1) Desert Warthogs always have distinctively backward curled tips to the ears -a feature never seen in Common Warthogs.

2) Desert Warthogs have a pronounced infra-orbital swelling (a prominent boney ridge below the eye) which is absent in Common Warthogs.

3) Desert Warthogs have pronounced hooked genal/jugal warts (the wart below and to the side of the eye). Common Warthogs have conical-shaped warts.

 

 

8600876580_9876d871d2_o.jpg

Desert Warthog (Phacochoerus aethiopicus) two boars at a small waterhole near the Galana/Sabaki river, Tsavo East, Kenya; July 2012.

Note in the image above the ears are clearly curled backwards, the upper cheek warts are distinctly hooked and there is an obvious swelling below the eye. Compare this with the Common Warthog headshot below:

 

8601989818_984443eb6b_o.jpg

Common Warthog (Phacochoerus africanus) boar; Masai Mara, Kenya; July 2007.

Note the rather narrow snout disc, the markedly curved canines, the lack of curling of the ears, the conical cheek warts and the lack of any significant swelling below the eye.

 

Much remains to be discovered about the Desert Warthog -especially in terms of its behaviour and ecology. It does however seem to favour flat semi-arid sandy scrub but avoids stony areas and coastal scrub. The natural range includes Somalia, Djibouti, Ethiopia, Kenya and possibly Eritrea. In Kenya it was previously thought that the Desert Warthog was not found south of the Tana river however its range extends through Tsavo East and south of the Galana/Sabaki river up to and including some parts of Tsavo West where it has recently been found to be sympatric with Common Warthog. Desert Warthogs have also been identified in Samburu NR and Meru NP.

 

If you are ever in Tsavo East, Meru or the Samburu area then check out any warthogs you come across as there is a fair chance that they will be Desert Warthogs (the warthogs of the Laikipia plateau westward are apparently all Common Warthogs).


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Interesting. Thank you for the story and pictures. Learning new facts is always good.

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@@Rainbirder

 

Thank you for a truly excellent post - one of the best contribution I have read on ST in recent times (I wish it would be possible to click the "like" button multiple times....).

 

I did not know Desert Warthog are occurring also south of the Tana river. Very interesting.

 

Personally, I have seen them in the Matthews' Range and in Meru. As to Ethiopia, the warthogs I have encountered on the highlands and central Rift Valley were Common Warthog, whilst those in Ali Dege (towards the Danakil) were Desert Warthog (I do not remember about Awash - not really sure I have even a warthog sighting there).

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Thank you @@Rainbirder - I don't think I would have even noticed if you hadn't explained the differences, I would have probably passed it off as "just another warthog".

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Posted (edited)

Interesting thread @@Rainbirder. Here are my contributions:

 

gallery_6003_624_427846.jpg

Ishaqbini Conservancy, Kenya

 

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Tsavo West National Park, Kenya

 

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Meru National Park, Kenya

 

The ones in the above photo are a bit tricky. I say it's probably a desert warthog. What say you @@Rainbirder?

Edited by Safaridude
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Nice images!!! @@Safaridude

 

The Ishaqbini and Tsavo West hogs show all the features of Desert Warthog but the Meru pigs look more like Common to me --but I'm by no means definite.

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Posted (edited)

Nice images!!! @@Safaridude

 

The Ishaqbini and Tsavo West hogs show all the features of Desert Warthog but the Meru pigs look more like Common to me --but I'm by no means definite.

 

Now I am not sure...

 

One thing I am sure about is this is a very informative thread you started. Thank you.

Edited by Safaridude
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@@Safaridude

 

Ken, in the Meru pigs image the ears are pointed rather than back curled, the jugal warts are conical, the canines quite curly and there is no significant infra-orbital swelling (which is a reflection of the underlying zygomatic arch thickening due to enlarged sinuses) which is why I thought they were Common Warthogs.

 

I did a bit of research on the internet prior to posting this thread and came across a number of images labelled as Desert Warthog which don't show the features descibed above but have been labelled as Desert Warthogs because they were photographed in arid habitats. The nominate subspecies of Common Warthog can be found in quite arid areas including Mali, Mauritania, Senegal, Chad and South Sudan. I have seen them in arid bush in Kiang West NP in The Gambia.

I came across this: http://www.huntineurope.com/us/p_maritania-warthogs.htm -these are clearly Common Warthogs as incisors can be seen in the lower jaw of the beast on the right. Unfortunately unless you know a few good warthog jokes and can get them to smile it is very difficult to glimpse the incisors in the field. ;)

 

It would seem that Desert Warthogs are really confined to the Horn of Africa and into Kenya. However matters are complicated by the fact that a subspecies of Common Warthog known as the Eritrean Warthog (Phacochoerus africanus aeliani) can also be found in Eritrea, Ethiopia, Djibouti and Somalia.

 

 

 

 

 

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Thank you @@Rainbirder for this great post and for all the valuable comments it generated!

I agree, the animals in the picture from Meru @@Safaridude are common warthogs. Both species of warthog occur in Meru National Park.

 

We just posted a request for additional warthog records from the Horn of Africa. If you have records to share or for additional information please visit:

http://safaritalk.net/topic/14945-request-for-warthog-records-from-the-horn-of-africa/ or wildsolutions.nl

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Hi @@Rainbirder,

Thank you so much for your post and fantastic photos ! I have just reregistered as a new member in order to send you a message. I hope you receive it.

I am researching the extinct Cape Warthog and read that the Desert Warthog is a living relative. I am a charcoal artist and wish to seek permission to use your photo as reference material for my original one-off artwork. My exhibition is focused on extinct species.

Please email me if you did not receive my message.

mali_moir@hotmail.com

 

Thank you, its all fascinating and wish I knew more warthog jokes .... :)

Mali

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Dear Mali that sounds very interesting and I love to see your desert warthog work! Would that be possible?

 

Thanks you and regards from Kenya,

 

Yvonne

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