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Monday, 23 December 2013

The Maned Wolf - a lesson in deductive dentition

This is a South American canid, the Maned Wolf.

File:Maned Wolf 11, Beardsley Zoo, 2009-11-06.jpg

This "dog" is a true omnivore, not unlike homo sapiens. It supplements a diet of meat (frogs, fish, lizards and other small game) with fruit, tubers, and sugarcane. These supply up to 51% of its diet. It does not do well in captivity without vegetable foods, In the wild it is susceptible to infestation by the Giant Kidney Worm (Dioctophyme renale)a potentially lethal roundworm it is exposed to by eating fish. It prefers the fruit of the Wolf Apple (Solanum lycocarpum) or lobeira, a tomato like fruit (also related to the Goji or Wolfberry) which is believed to protect it against this parasite (1).
Cindy Engel writes in Wild Health (a 2002 book which is recommended reading for anyone interested in Ancestral Health):
"Although this fruit is more plentiful in certain seasons, the wolf works hard to eat a certain amount throughout the year... researchers at the Brasilia zoo found that when packs of captive wolves were fed lobeira daily, they survived. If lobeira was withheld, all the wolves died. Postmortem examinations revealed giant kidney worm infestations, and it was suspected that lobeira might be controlling these worms in the surviving wolves".
The Maned Wolf also seems unusually susceptible to cancers in captivity (2)

Whether or not the maned wolf is self-medicating, we can learn a lot by looking at its teeth:
File:Manedwolfskull.jpg
Teeth adapted, as the Maned Wolf is, to a diet that can be 51% plant based.

Let us compare that with the dentition of Homo Sapiens, a creature adapted to eating a diet similar to that of the Maned Wolf, with, on average, a broadly similar split between animal and plant foods:

Dentition   overview

We can clearly see that the dentition of a species need not be specific for its adapted diet. The Maned Wolf finds animals hard to catch and kill; it is not going to lose its carnivorous dentition because it eats fruit (although too much indulgence in the sugar cane could conceivably have that effect in individuals). The ancestral savannah-dwelling hominid, perhaps a former insectivore and fruitarian, finding itself "tuskless in Eden" in Robert Ardrey's evocative words from African Genesis, survived by developing tools that do the work the Maned Wolf's incisors do. Humans have not needed to trade away teeth that are useful for gripping the ends of the cords used to tie spearheads onto shafts, as well as for crushing seeds and roots. We can chop and stab and saw where the Maned Wolf can only tug and gnaw. The leg joints of quadraped mammalian carnivores are well designed for maximum force in tugging as well as speed in leaping and running.

Man is neither of these things (below), but it's fair to say that for quite a few aeons now he has had more in common with the dog than with the sheep. Especially if that dog is the Maned Wolf.



For comparison, the dentition of a Kangaroo, a marsupial herbivore which has evolved separately from the sheep:


This is the Maned Wolf's closest living relative, the Bush Dog, in flagrante delicto. This tough and gregarious 5-8 Kg canid can hunt the 40 Kg peccary, and a pack has been seen hunting a 250 Kg tapir.
It seems to be a wholly carnivorous creature. 


File:Bushdogs.jpg

The legs of the Bush Dog are adapted for strength in tugging at its larger prey, whereas those of the Maned Wolf are more suited for leaping on the small, swift creatures that make up its animal diet.

(1) Conservation of the Maned Wolf: fruitful relationships in a changing environment
Orin Courtenay, Canid News 1994
(2) High Incidence of Ovarian Tumours in Maned Wolves (
Chrysocyon  Brachyurus) at the National Zoological Park, Munson 1991



6 comments:

Galina L. said...

Primates have an extended knowledge about medicine property of plants and know how to fight parasites, and it is easy to imagine that many plants came to a human diet the same way. I was thinking about it while making a mustard last time- it has no nutritional value, and doesn't taste well, unless you add vinegar, salt, put it on meat. The seeds and raw powder are not hot at all, just slightly bitter, but a moisture exposure really turns the heat on. No animal would eat it twice.

George Henderson said...

In Wild Health, Cindy Engels states something I've also thought, that plants can come into the diet as medicines as well as calories, and their problems are often those of medicines - toxicity and unwanted effects. She puts this a lot better than I can. Many animals other than primates use medicines. And also antidotes to plant toxins, especially clay.

Edward Edmonds said...

One of the more interesting things I've seen this year; besides those spiders that build tiny fences.

There are some monkeys in the Ethiopian highlands that have "carnivorous" looking teeth, they were featured in 2 BBC features I think one was Human Planet, and the other was Planet Earth, they eat only grasses, and they raid the local highland wheat farms. Apparently it is a problem as a group of them can eat a good amount of the wheat within a short time span and during harvest they have to have people watching out for them to scare them off. I wondered if they just started eating wheat when the farmers appeared there or if the had been eating wild wheat varieties. Not sure.

Chip Spitter said...

Aww, so cute how the Bush Dogs are cuddling. Oh...dear...

:)

Happy Festive Season, George.

ItsTheWooo said...

great entry George, it is silliest vegan logical fallacy to evoke dentation to prove what diet is or is not healthful for any species.

George Henderson said...

Some breeds of sheep and deer eat birds, perhaps since forever, and this hasn't altered their teeth anymore than the maned wolf's ancient need for fruit has altered its teeth.
Bears do seem to evolve in this manner: Wiki says
Unlike most other members of the Carnivora, bears have relatively undeveloped carnassial teeth, and their teeth are adapted for a diet that includes a significant amount of vegetable matter. The canine teeth are large, and the molar teeth flat and crushing. Considerable variation occurs in dental formula even within a given species. This may indicate bears are still in the process of evolving from carnivorous to predominantly herbivorous diets. Polar bears appear to have secondarily re-evolved fully functional carnassials, as their diets have switched back towards carnivory.

Further,homonids seem to be a unique family tooth-wise. At some point the relationship between teeth and diet ceased to matter, and that point probably marks the advent of hunting and butchering tools, fire, and intelligent organisation.