1. The Origin of the Dog

 

2.The dog's evolution

 

3.The Origin of the Dog Revisited
1. The Odyssey of the Word "Molossus"

2. The Evolution of brachycephalic molossoid dogs

1. Man's relationship with animals

2. Dog and Human societe

3. The dog shows in Europe

1.The Vision in dogs

2. The hearing of the dog

3. The sense of smell in dog

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The Origin of the Dog Revisited
Janice Koler-Matznick
5265 Old Stage Road, Central Point, OR 97502 U.S.A.
jkoler@ccountry.com
Abstract
The most widely accepted hypothesis of the origin of the dog, Canis familiaris, is that the
dog is a domesticated gray wolf, Canis lupus. This paper reviews the evidence for this
conclusion, finds many unanswered questions and conceptual gaps in the wolf origin
hypothesis, and explores the alternative hypothesis that the most likely ancestor of the
domestic dog was a medium-size, generalist canid.
Introduction
Currently, there is a general consensus that the sole ancestral species of the
domestic dog, Canis familiaris L. 1758, is the gray wolf, Canis lupus L. 1758 (Coppinger
& Smith 1983; Clutton-Brock 1984, 1995; Olsen 1985; Wayne 1986; Tchernov &
Horowitz 1991; Morey 1992; Wilson and Reeder 1993; Cohn 1997; Vilà et al.1997;
Budiansky 1999; Crockford 2000; Coppinger & Coppinger 2001). However, there is at
least one competing hypothesis that is equally plausible, yet has not been given adequate
evaluation in the published literature. The dog origin alternatives are: (1) an origin from
golden jackal (Canis aureus) (Lorenz 1954); (2) an origin from hybrids of wild canids
(Darwin 1875; Clutton-Brock 1977; Brisbin 1997); or (3) an origin from a wild Canis
other than jackal or C. lupus (Epstein 1971; Zeuner 1963; Fox 1973; Manwell & Baker
1983). Jackal ancestry of the domestic dog (hereafter DD) can be dismissed due to the
large genetic distance separating the two (Wayne & O'Brien, 1987; Wayne et al., 1991a).
Although a hybrid origin (e.g., Canis simensis or Cuon alpinus with small subspecies of
C. lupus), suggested by several authors to account for the sudden shift from wolf to
primitive dog morphology, cannot be ruled out, currently no direct evidence supports this
hypothesis. In this paper, I review selected behavioral, morphological, molecular, and
fossil information relative to the competing hypotheses of wolf origin and wild canid
origin. Appendix I provides my working definitions of terms with variable meanings.
Discussion
Behavior
Many hypothesize that the wolf was pre-adapted for domestication as it is one of
the rare pack-living canids. Gregarious social structure facilitates domestication because
humans manage domesticants through social domination (Clutton-Brock 1981, 1994,
1995; Olsen 1985; Hemmer 1990). However, wolf behavior has significant differences
from the behavior of domesticated non-predatory species. Unlike most gregarious noncarnivore
species, wolves are able to survive as individuals independent of the group and
within the pack have diverse roles (Mech 1970; Sullivan 1978). With careful
conditioning using modern methods, wolves can be tamed (Crisler 1958; Klinghammer &
Goodman 1985), but not trained to follow commands reliably. Although they respect
limits on inter-individual conduct, wolves resist human direction of their activities and
2
inhibition training (Frank & Frank 1983; Klinghammer & Goodman 1985; Coppinger &
Coppinger 2001). This is why there are no wolf acts in circuses. In a stable wolf pack,
usually only the dominant pair reproduces. Therefore, wolves have a biological
imperative to move up in the hierarchy (Mech 1970), making sexually mature captive
wolves dangerous (Fox 1971; Klinghammer & Goodman 1985).
Group social organization is not an invariable pre-requisite to domestication.
Hamilton-Smith (1839) reported that South American indigenous people tamed a fox,
Dusicyon culpaeus, which bred in captivity and was used as a hunting aid. Thus,
domestication of a non-pack canid is possible. Another domesticated carnivore, the nongregarious
cat, Felis sylvestris, adapts well to group living (Clutton-Brock 1981).
The lack of wolf-like pack forming behavior in DDs is sometimes ascribed to
their retention of the behavior of immature wolves before integration into the pack
(Coppinger and Schneider 1995). However, many DDs reside amiably in groups, and the
response of primitive dogs to group confinement is variable (Scott & Fuller 1965; Corbett
1995; Koler-Matznick, Brisbin & Feinstein 2001). The DD's variable social tolerance and
absence of hierarchical pack formation could also be due to natural (niche related) or
artificial selection for neotenous behavior compared to a non-pack-forming ancestor, or
to selective emphasis on gregariousness within a variable ancestral social repertoire.
Monogamous pair social structure with temporary family groups is the most common
pattern in canids (Kleiman 1967; Ewer 1973; Kleiman & Brady 1978). Therefore, the
lack of long-term hierarchical pack formation in the DD is what would be expected if the
ancestors of DDs was not a wolf, but rather a more typical canid.
The statement "Man domesticated the wolf," implying human proactive effort,
appears in most speculations about DD origin. Vilà et al. (1997) conclude that the DD
may have originated from tamed wolves 135,000 YBP, when Homo sapiens was a young
species (Wolpoff & Caspari 1996). This hypothesis has conceptual gaps. The question of
how humans created a domesticated wolf between 15,000 YBP, the oldest estimate from
the fossil record for DD (Clutton-Brock 1995), and 135,000 YBP, the highest estimate for
separation of DD/wolf from mtDNA (Vilà et al. 1997), is rarely addressed.
Further, the reasons for wolf domestication need to be analyzed in the context of
human cultural evolution. The value of domesticating such an animal is generally
assumed to be to assist with large game hunting or to act as guards (e.g., Clutton-Brock
1977, 1995; Olsen 1985; Wayne 1986; Cohn 1997). Wolves hunt large prey
cooperatively, thus some propose wolves easily adapt to hunting as human partners
(Olsen 1985; Clutton-Brock 1999). The time of separation of DD and wolf is estimated to
be between 76,799 YBP to 135,000 YBP from mtDNA (Okumura et al. 1996; Vilà et
al.1997). At that time, humans had only clubs, axes, spears and knives (Gowlett 1993).
With these tools, stealth and ambush are used to secure large prey. Wolves are extremely
difficult to condition to reliably inhibit inherent behavior (Fox 1973; Frank & Frank
1983, 1987). They instinctively chase large prey, and thus would hinder humans hunting
cursorial game, rather than assist. Wolves are also extremely food-possessive
(Klinghammer & Goodman 1985; Goodman & Klinghammer 1990; Koler-Matznick
personal observation). If hungry tamed wolves did secure prey, humans would have to
fight them for it.
Dingoes provide a modern example of tamed wild canids as hunting aids (Hayden
1975). The Aboriginies used dingoes to locate small prey that goes to ground or trees, but
3
prevented dingoes from following when hunting kangaroos because the dingoes chased
them off (Meggitt 1965). If tamed wild canids are not useful aids for hunting cursorial
game and smaller canids are as proficient at locating smaller prey, there is no reason to
keep large wolves in domestication.
Humans could be easily kleptoparasitic on small to medium-sized proto-dogs that
hunted independently of humans. Indian pariah dogs occasionally hunt deer. Humans
encourage this. Pariah dogs (11 – 16 kg) usually range only near villages, so their prey is
readily confiscated (Fox 1984; Corbet & Hill 1992). Smaller prey brought back by pariah
dog dams for their pups may also be confiscated (Bulmer 1976). Modern humans have
sometimes followed the inoffensive Indian dhole (Cuon alpinus) (10 – 20kg), a pack
hunter, to appropriate its kills (Stewart 1993). Confiscating prey from wolves would be
more risky.
The assumption that tamed wolves would be effective guards is not supported by
behavioral studies. All wild canids, including dingoes and NGSDs, make poor guards
(Manwell & Baker 1984; Koler-Matznick personal observation). They will not physically
defend even their own offspring if their personal survival is threatened. Wolf alerting
behaviors would notify humans danger was in the area, but alerting behavior is performed
equally well by smaller canids such as aboriginal dogs (Coe 1994) and NGSDs (Koler-
Matznick personal observation).
Knowledge of innate modern wolf behavior indicates that early humans would
have been wolf prey. In contemporary India, wolves prey upon children (Mech 1996;
Kumar 2001). Before the development of long-range weapons and persecution by
agricultural/pastoral peoples, wolves would have been bolder. Fearless wolves that
associate man with food may injure humans (Mech 1998). For their safety, pre-modern
humans would have instilled wolves with fear. However, prior to the domestication of
livestock, the presence of non-threatening jackal-size canid scavengers could have safely
been tolerated. If the DD ancestor was a small canid frequently encountered waiting for
scraps at kill sites, through familiarity they may also have been permitted around camps
for cleanup duty.
Wolves require substantial amounts of high-protein food and have extended
adolescent periods of up to two years during which they must be supported while learning
to hunt large game cooperatively (Crisler 1958; Mech 1970). The smaller, more
precocious canids, such as dingoes, are independent before one year (Ginsberg &
Macdonald 1990). Dingoes commensal with Aboriginal hunter-gatherer groups are fed
scraps, otherwise fending for themselves in the game-depleted areas around camps.
Meggitt (1965) notes that tame dingoes could be distinguished from wild specimens due
to their poor condition. Wolves in similar circumstances would be more nutritionally
compromised. Even if they could eventually train wolves to hunt large prey in accord
with human techniques, it is unlikely that pre-modern humans would provide the
substantial amount of care-taking needed to support wolves through maturation.
The earliest proto-DD/human association was without doubt voluntary.
Individually tamed wild "pets" kept within the species' natural environment, if not
confined, at maturity usually join their wild conspecifics. Early Holocene humans had no
means of keeping canids confined. Many authors answer the question "Why did wolves
choose to become commensal?" by hypothesizing that wolves were attracted by camp
refuse (e.g., Coppinger & Smith 1983; Tchernov & Horowitz 1991; Budiansky 1999;
4
Crockford 2000; Coppinger & Coppinger 2001). That hypothesis is unconvincing,
especially before 12,000 YBP, the date usually proposed for the founding of permanent
settlements. Depending upon the area, season and the size of the group, nomadic huntergatherers
may use almost all the nutritious portions of any carcass (Blumenschine &
Marean 1993; Jones 1993; Oliver 1993), so camps frequently generate little nutritious
refuse that would support wolves (Brain 1967; Davis 1987; Jones 1993). While wolves
are opportunistic scavengers (Brisbin 1977; Boitani 1983), there would not have been
enough nutrition available at campsites to support a breeding population of wolves on its
way to domestication. Given the paucity of dependable, nutritious waste, without a
compelling reason (e.g. local prey base crash) it would be highly unusual for a large
predator to make a niche shift to refuse-scavenger. No such compelling reason has been
offered.
Failure to investigate primitive dogs has resulted in spurious reasoning from
modern, highly derived DDs. The wolf, largest of the living canids, becomes annually
reproductive at two years (Ginsberg & Macdonald 1990). Most modern DDs become
sexually mature before one year of age and average two reproductive cycles yearly. The
wolf-to-dog hypothesis assumes that, in the pariah niche, faster sexual maturity and
increased fecundity were strongly favored, so wolves rapidly became smaller with biannual
reproductive cycles not entrained to the environment (Clutton-Brock 1995;
Coppinger & Coppinger 2001). However, ancient pariah and primitive dogs have annual
reproductive cycles entrained to the environment (Coe 1994; Corbett 1995; Pal, Gosh &
Roy 1998; Koler-Matznick, Brisbin & MacIntyre 2000), and, like similar-sized wild
canids, come into first estrus at about one year old (Ginsberg & Macdonald 1990).
The specialized wolf is an unlikely candidate for the behavioral flexibility
required to adapt to the pariah niche. Most wild animals that have adapted to
anthropocentric environments are generalists: e.g., raccoon (Procyon lotor); opossum
(Didelphis virginianus); rat (Rattus norvegicus, Rattus rattus); and mouse (Mus
domesticus, Mus musculus). Wolves have never been reported as voluntary commensals,
whereas generalist canids, including coyote and red fox (Vulpes vulpes) readily reproduce
in metropolitan areas (Gier 1975; Kleiman & Brady 1978) and golden jackals scavenging
around human settlements can become a nuisance and subject to eradication (Harrison &
Bates 1991).
Morphology
Primitive dogs have typical Canis conformation (Fig. 1). Dog characters that
differ from wolves are generally attributed to artificial selection, but these analyses
typically begin with the assumption dogs are descended from wolves. Most authors
conclude that, compared to wolves, adult DDs have relatively reduced rostrums, elevated
frontals, wider palates, broader craniums, and smaller teeth (Hildebrand1954; Clutton-
Brock, Corbet & Hills 1976; Olsen 1985; Wayne 1986; Hemmer 1990; Morey 1990).
Others point out that these traits vary, with overlap between and variation within the two
species (Crockford 1999; Harrison 1973). Because wolf cubs have similar relative skull
proportions as DDs (Wayne 1986), this is considered evidence that the DD is a neotenic
wolf due to conscious or unconscious artificial selection for juvenile appearance, or to a
pleiotropic effect of selection for juvenile behavior (Clutton-Brock 1977; Belyaev 1979;
Wayne 1986; Coppinger and Schneider 1995). Body size reduction from wolf to early
5
Figure 1. A young male New Guinea singing dog from the North American captive
population illustrates typical primitive dog morphology. Photo credit: Photosynthesis
Studio.
DDs is attributed to niche selection (e.g. Olsen 1985; Morey 1992;Coppinger &
Coppinger 2001). For example, Morey (1992:199) says: "Results [of a comparison of
morphology of early DDs to morphological change in C. lupus during ontogeny ]…are
consistent with a hypothesis that early domestic dogs are evolutionary paedomorphs,
products of strong selection for ontogenetically channeled size reduction and alterations
of reproductive timing associated with the new domestic way of life."
Wayne (1986) compares DD skull morphology to wild canid species and
concludes that the DD is closer in skull morphology to the other canids in his study
(Canis latrans, Canis aureus,
Canis adustus, Canis mesomelas, Cuon alpinus, Lycaon pictus), than to the wolf. Unlike
previous authors (e.g., Stockhaus 1965), Wayne (1986) also concludes that his DD
samples did not have significant relative shortening of the rostrum compared to wolves.
The previously reported reduced rostrum length of DD's, assumed to be a secondary
effect of captivity or of neoteny (Stockhaus 1965; Olsen 1985; Clutton-Brock 1984), is
thus called into question.
Although no discussion of a functional reason for the dog's elevated frontals was
located, Endo et al. (1997) show that the Japanese wolf (Canis hodophilax), with typical
low frontals, had sinuses less developed in the dorso-ventral direction compared to the
6
Akita dog, which had elevated frontals. Endo et al. (1997) suggest that the smaller
frontal sinus may have an influence on respiratory function.
Dahr (1942) concludes that the shape of the DD brain case is closer to the coyote
than the wolf, and most closely resembles the coyote when the DD is between jackal and
wolf size. Manwell and Baker (1983) review Dahr's findings and additional dental data
for DDs, wolves, and jackals, and conclude that the DD most closely approaches wild
Canis parameters at body sizes below that of any living subspecies of wolf. They
hypothesize the DD ancestor was probably within the range of 13.6 – 20.5 kg. This is
about the size of dingoes and considerably smaller than the 27 - 54 kg given for living
wolves (Mech 1970).
Dog dentition is relatively less robust than the wolf's (Olsen 1985; Hemmer
1990). This is attributed to relaxation of selection when wolves became commensal
scavengers or to artificial selection (Olsen 1985; Clutton-Brock 1995). Kieser and
Groeneveld (1992) compared the mandibulodental measurements of jackals (Canis
adustus, C. mesomelas) and Cape foxes (Vulpes chama) to equivalently-sized DDs. They
found that the canines of the other canids tended to be slightly smaller and their second
molars larger compared to DDs. Otherwise, the proportions were essentially the same in
all species. They conclude: "...the teeth of canids appear to have evolved in concert with
one another and relatively independently of differences in dimorphism, size or functional
demands" (ibid, p. 423). If correct, this calls into question the assumption that dog teeth
are relatively small due to recent selection, suggesting the possibility that dog dentition is
plesiomorphic from a progenitor smaller than the wolf.
Some diagnostic dog characters have no evident connection to paedomorphism.
Of these, two are mandibular. The dog's coronoid apex has a posteriorly directed curve
not present in wolves, except some C. l. chanco and C. l. pallipes (Olsen 1985; Hemmer
1990). The presence of this character in C. l. chanco is cited by Olsen (1985) as evidence
that the dog may have descended from this subspecies. Neither Olsen (1985) nor Hemmer
(1990) mention possible dog introgression as a source of this variation. The ventral edge
of the dog horizontal ramus has a convex curve not present in C. lupus (Olsen 1985;
Clutton-Brock 1995). No discussion of possible significance of the difference in the dog
mandible shape was found in the literature. However, Biknevicius and Van Valkenburgh
(1997) note that the horizontal ramus of bone-processing predators is thicker dorsoventrally
at the point caudal to the site of bone processing. Perhaps this thickening of the
dog ramus was a functional niche adaptation in the dog ancestor.
The bullae of DDs are relatively smaller and flatter than those of wolves
(Harrison 1973; Clutton-Brock, Corbet & Hill 1976; Nowak 1979; Olsen 1985; Wayne
1986), a difference attributed to relaxed selection under domestication. Presumably, the
bullae became smaller because DDs did not need the wolf's acute hearing. Bullae
function as air chambers behind the tympanic membrane, damping the chain of auditory
ossicles. According to Ewer (1973), bulla shapes facilitate increased resonance effects
and sensitivity to specific frequencies. Differently constructed bullae are sensitive to
different frequencies, but shape and size may not be correlated with general acuity. No
references to studies of comparative auditory acuity of wild Canis species and DDs were
located. Those carnivores with highly inflated bullae are predators that need to hear high
frequency sounds, whereas the bullae of largely nonpredaceous omnivores, such as bears
(Ursidae), are relatively small (Ewer 1973). Without evidence of selective forces
7
directing change from wolf to dog conformation, the parsimonious explanation for the
observed differences is that the bullae retain ancestral shape.
There are additional characters separating DDs and wolves that are rarely mentioned in
the literature. Atkins and Dillon (1971) describe the superficial brain morphology of
jackals (C. mesomelas, C. aureus), coyotes, wolves (C. lupus, C. rufus), and DDs. They
conclude that the cerebellum of the DD most closely approximates the coyote, which is
closely allied with the jackals, and that wolves show numerous brain traits distinct from
the other species. Wolves also have serological and biochemical traits distinct from DDs
(Leone and Wiens 1956; Lauer, Kuyt & Baker 1969).
A trend toward neoteny, if indeed that is present in the dog, is a recognized mode
of adaptive evolution (Gould 1977). There is no reason to attribute neotenic traits to
artificial selection. The most parsimonious explanation for the different morphological
characters of dogs and wolves is that the DD ancestor was adapted to a different niche
than the wolf.
Fossils
A problem for the wolf-origin hypothesis is the absence of fossils intermediate
between wolves and the small early DDs of 9,000 - 14,000 YBP (Olsen 1985; Benecke
1987). Vilà, et al. (1997) explain this by speculating that proto-DDs showed little size
change before permanent settlements, an argument incompatible with the hypothesis of
strong selection for size reduction when wolves entered the scavenger niche. A few fossil
canid skulls have been classified as tamed wolves or wolf-to-dog transitional forms
because of their relatively reduced rostrum lengths and large, crowded teeth (Ovodov
1998), characters present in some wolves (Clutton-Brock 1995; Clutton-Brock, Kitchener
& Lynch 1994) and possibly attributable to dog introgression.
Pei (1934) and Olsen (1985) describe one possible candidate for the ancestral dog,
Canis lupus variabilis. Along with C. l. pallipes, B. Lawrence (1967) mentions C. l.
variabilis as a possible dog ancestor. This canid was found at Choukoudian, China, in
layers dating 200,000 YBP - 500,000 YBP, associated with Homo erectus or H. sapiens
artifacts, and in the layer predating Homo evidence (Kahlke & Chow 1961). Pei (1934)
suggests the fossil Chinese canid specimens previously named Canis chihliensis
(Zdansky 1925; Teilhard de Chardin & Piveteau 1930) should be C. l. variabilis. C. l.
variabilis is also known from Lantian in Saanxi Provence (Hu & Qi 1978), so it had a
wide range in time and space. At the time Pei wrote, C. lupus variabilis was four times
more common than "true" C. lupus at Choukoudian. Pei (1934) describes this diminutive
"wolf" as exhibiting variation in size and tooth adaptations, stating that it's skull differs
from the typical wolf in much smaller size (about 175.0 mm total length for a large C. l.
variabilis specimen), with a more slender muzzle and weak or absent sagittal crests. In
addition, the lower border of some C. variabilis mandibles is "…strongly convex as in
the dog…" (Pei 1934:15). The one trait aligning C. l. variabilis with wolves is relatively
large carnassial teeth (P1 20.4 – 23.0 mm; M1 22.0 – 24 mm). Pei concludes: (1934:17):
"Although no sharp line can be traced between the above described Canis and a true
lupus, the marked differences found in the size, and in the cranial characters, seem to be
sufficient for creating, at least, a new variety, Canis lupus variabilis, for the Choukoudian
. . . small wolf."
8
The conspecific status of C. l. variabilis, a presumably extinct but diagnostically
distinct canid sympatric through time and space, with C. lupus, is open to question. Pei
(1934) states that he adopted a new C. lupus sub-specific designation for this
Choukoutien canid chiefly for stratigraphical convenience. Olsen's justification for
naming this canid C. lupus is that he felt the assignment to this category was inadequate,
but that it is always better to assign to a general category if there is not enough material to
be more specific (S. J. Olsen, personal communication 1996). However, C. lupus is a
defined species, not a "general category." Additional C. l. variabilis finds were made
after Pei's publication where they were designated as "common." So, they remained
distinct from sympatric C. lupus for tens of thousands of years over a large geographic
range (Olsen 1985). Designation of C. l. variabilis as simply Canis variabilis, or
retention of the earlier C. chihliensis designation, may have significantly altered
inference concerning the origin of the dog.
Some authors comment on the resemblance of the oldest European DD finds to
the dingo (e.g., Dahr 1942; Degerbøl 1961). Higham, Kijngam & Manly (1980)
examined dog skulls from Ban Chiang, Thailand, and determined that those dated 3,900
YBP are nearly identical to the living dingo-like pariah dogs of the area. Australian dingo
skulls from about 3, 900 YBP are also essentially identical to modern dingo skulls
(Gollan 1982). Although he offers no evidence, Corbett (1995) hypothesizes that several
races of ancient dingo-like pariah dogs are domesticated dingoes. Today, these ancinet
pariahs are being genetically mixed with, and in some areas swamped by, imported
European and Asian DDs (Meggitt 1958; Titcomb 1969; Corbett 1995). But the dingo
morphotype apparently was very widespread before recent artificial selection for variable
DD morphotypes. It is also the morphotype that predominates in long-term free-ranging,
free-breeding modern DD populations after many generations (Brisbin 1977, 1997).
Such populations never assume wolf morphology.
Molecular Evidence
According to Wayne, Van Valkenburgh and O'Brien (1991), Nei's genetic
distance between dog and wolf, based on one-dimensional allozyme electrophoresis, is
0.042. This is slightly greater than the 0.030 reported for leopard (Panthera pardus) and
jaguar (Panthera onca). Nei's genetic distances among bear species from single-copy
DNA hybridization are slightly lower than the dog and wolf's (Wayne,Van Valkenburgh
& O'Brien 1991), yet they have not been declared the same species because of the
relatively small genetic/molecular distance.
The available mtDNA evidence is interpreted as indicating that the dog and wolf
could have separated about 76,000 to 135,000 YBP (Tsuda et al.1997; Vilà et al. 1997).
Vilà et al. (1997) found only one mtDNA haplotype shared by wolves and DDs, 25 types
specific to dogs and 26 to wolves. Six of the unique dog types inter-grade with wolf
types on relatedness diagrams (Vilà, et al. 1997). Tsuda et al. (1997) also found that dog
haplotypes, while different, inter-graded with wolves in a neighbor-joining analysis.
From this statistically close relationship of mtDNA types, both Vilà et al. (1997) and
Tsuda et al. (1997) conclude that the wolf is the DD's ancestor. However, in Vilà et al.
(1997) 19 dog types (including primitive dogs') grouped together separately from wolves,
indicating they are monophyletic. The maximum within-dog divergence given is 12
substitutions, the divergence between wolves/dogs as 12 substitutions and between dogs
9
and coyote/jackal as 20 substitutions and two insertions. Thus, in mtDNA, dogs are more
distantly related to jackals/coyotes than to wolves. The mtDNA of C. l. pallipes and C. l.
arabs, the wolves closest to primitive dog size and morphology so often proposed as the
DD ancestor (e.g., Gollan 1982; Corbett 1995), are no closer to DD types than other C.
lupus (Vilà et al. 1997). No study found compared dog mtDNA to Canis simensis or
Cuon alpinus.
The mtDNA studies cited above conclude that the DD is a wolf without
addressing the inherent limitations and assumptions of such studies. MtDNA is
essentially a single locus marker, inherited in a clonal fashion, and is only effective at
estimating maternal lineage relationships. The inclusion of nuclear DNA in analyses
would be more meaningful and might lend clarity to the heterogeneity observed in the
mtDNA phylogenetic trees. Cronin (1993: 343) shows that a relatedness tree based on
mtDNA sequence divergence may not be the same as a phylogenetic tree, because
recently differentiated groups will often share a considerable amount of incompletely
sorted genetic characteristics. Incomplete lineage sorting is common among closely
related species with a recent common ancestor. Wayne and Ostrander (1999) emphasize
that, while molecular genetic data seem to support the origin of dogs from wolves, dogs
may have descended from a now extinct species of canid whose closest living relative
was the wolf.
Due to descent from a common ancestor, several species have populations with
mtDNA closer in sequence to another species than to conspecific populations (Carr et al.
1986; Cronin, Vyse & Cameron 1988; Avise, Ankey & Nelson 1990; Cronin et al. 1991).
There are also examples of introgressions of mtDNA between species, which could be
misinterpreted as evidence of conspecific status if analyzed without regard to other
diagnostic characteristics (Avise 1986; Cronin 1993).
Wolves and DDs have been sympatric for thousands to tens of thousands of years,
yet only one mtDNA type is shared. Although occasional hybridization may have taken
place in some areas, panmixia has not occurred despite the fact that until the last few
hundred years most dogs free-ranged, breeding at will (Clutton-Brock 1981; Boitani
1983; Boitani et al. 1995; Nowak 1995; Randi & Lucchini 2002). For example, Indian
pariah dogs are about the same size as the Indian wolf (C. l. pallipes), one of the
candidates for the dog's "ancestral wolf" (Olsen 1985; Hemmer 1990; Corbett 1995),
their estrus seasons coincide, the wolf population today is small and fragmented, yet they
are not known to hybridize (Oppenheimer & Oppenheimer 1975; Shahi 1983; Pal, Gosh
& Roy 1998). If dogs and- wolves did not have relatively effective behavioral barriers to
interbreeding, they would share most if not all of their mtDNA types. Therefore, the dog
and wolf seem to meet the criteria of the Biological Species Concept (O'Brien and Mayr
1991).
The shared or very similar mtDNA types are not necessarily of wolf origin.
Crockford (2000) hypothesizes that the similarity of dog/wolf mtDNA could be due to
genetic introgression of dog into the wolf population. Koop et al. (2000) found some precontact
Northwest American aboriginal dogs had mtDNA types closer to North American
wolves than to other DDs, concluding that these DDs may have originated from local
wolves. Crockford (2000) instead hypothesizes that perhaps these mtDNA haplotypes are
similar due to essentially rare unidirectional feral female dog to male wolf hybridization
occurring for so long that extant wolf populations have dog mtDNA.
10
Contemporary wild wolf/dog hybrids have been collected in Alaska (B. Yates,
personal communication 2001), Vancouver Island, B.C., Canada (Koop et al. 2000), Italy
(Randi & Lucchini 2002) and are known from the archaeological record (Walker &
Frison 1982). Vilà and Wayne (1999) suggest that, because of reproductive timing
differences, the direction of wolf/dog hybridization was probably female wolves to male
dogs (implying the shared mtDNA types are wolf). They overlook reports that show
male wolves do breed with female dogs (Gottelli et al. 1994) and coyotes (Wayne et al.
1991), and the offspring incorporated into the wolf population. Given the unpredictable
behavior of wolf hybrids and the difficulty of keeping F1 hybrids confined (Gloyd 1992;
Hope 1994; Marx 1994; Steinhart 1995) it is unlikely that prehistorically and in the recent
past, hybrids would have successfully integrated into the DD population. Crockford
(2000) points out that the genetic integrity of specimens used to represent wolves in most
DNA studies are not clearly defined, and concludes that the use of contemporary wolves,
or those from archaeological contexts, in comparative studies of mtDNA with DDs may
be misleading due to the possibility of long-standing introgressive hybridization with
dogs.
Conclusion
Manwell and Baker (1983 ) suggest that research on the origin of the dog had
been constrained by "disciplinary dogmatism": the strong, authoritative and oft-repeated
assertion that humans domesticated the dog from a gray wolf. They (1983:221) conclude
that although they cannot rule out a wolf origin, the most likely hypothesis is "…the
currently unpopular idea of the origin of the dog from a wild Canis familiaris." Since
1983, dogmatism about the origin of the DD has only increased, to the point that Wilson
& Reeder (1993) felt confident [accepting Wozencraft's] renaming C. familiaris as C.
lupus familiaris without discussion.
The morphological and molecular evidence discussed here, combined with a
consideration of plausible human and canid behavior, suggests that the hypothesis that
humans created the dog by purposefully domesticating the wolf is unlikely. The
hypothesis that wolves were voluntary commensals, and that wolf morphology rapidly
changed after adopting a pariah scavenger niche, is not supported by any evidence. Dogs
have several diagnostic morphological characters that are possibly plesiomorphic and not
by-products of artificial selection. The wolf and dog seem to be clearly separated but
closely related, universally sympatric species with effective reproductive isolation. Thus,
the current fashion of placing C. familiaris in synonymy with C. lupus is not supported.
The lack of agreed-upon dog fossils from before 15,000 YBP has been used as
evidence for the recent origin of the dog from the wolf. However, Olsen (1985) notes
there are many small Pleistocene "wolves" in the fossil record of Eurasia that need more
careful consideration.
The hypothesis that fits the available evidence most parsimoniously is that the
first DDs descended from a species of medium-sized generalist canid, a "wild C.
familiaris," that voluntarily adopted the pariah niche and remained commensal for an
extensive period before some populations became truly domesticated. If the inertia
created by the wolf-origin dogma can be overcome, and the problem considered without
preconceptions, perhaps investigation of possible functional origins of the morphological
differences between dogs and wolves, expanded nuclear DNA studies and re-evaluation
11
of the canid archaeological and fossil record will answer some of the unresolved
questions concerning our most ancient domesticant.
References
Atkins, D. L. and L. S. Dillon, 1971. Evolution of the cerebellum in the genus Canis.
Journal of Mammalogy 52(1): 96 -107.
Avise, J. C. 1986. Mitochondrial DNA and the evolutionary genetics of higher animals.
Philosphical Transactions Royal Society London [Biology] 312: 325 - 342.
Avise, J. C., C. D. Ankey and W. S. Nelson. 1990. Mitochondrial gene trees and the
evolutionary relationship of mallard and black ducks. Evolution 44: 109 - 119.
Belyaev, D. K. 1979. Destabilizing selection as a factor in domestication. Journal of
Heredity 70: 301 - 308.
Benecke, N. 1987. Studies of early dog remains from northern Europe. Journal of
Archaeological Science 14: 31 - 49.
Biknevicius, A. and B. Van Valkenburgh. 1997. Design for killing: craniodental
adaptations of predators. In Carnivore behavior, ecology, and evolution. 393 – 428, ed. J.
L. Gittleman. Cornell University Press, Ithaca, NY.
Blumenschine, R. J. and C. W. Marean. 1993. A carnivore's view of archaeological bone
assemblages. In From Bones to Behavior: ethnoarchaeological and experimental
contributions to the interpretation of faunal remains. 273 – 300, ed. J. Hudson. Center for
Archaeological Investigations Occasional Paper No. 21. Southern Illinois University,
Carbondale.
Boitani, L. 1983. Wolf and dog competition in Italy. Acta Zoologica Fennica 174: 259 -
264.
Boitani, L., F. Francisci, P. Ciucci & G. Andreoli. 1995. Population biology and ecology
of feral dogs in central Italy. In The Domestic Dog: its evolution, behaviour and
interactions with people. 217 – 244, ed. J. Serpell, Cambridge University Press,
Cambridge, UK.
Brain, C. K. 1967. Hottentot food remains and their bearing upon the interpretation of
fossil bone assemblages. Scientific papers of the Namib Desert Research Insitutue 32: 1
– 11.
Brisbin, I, L. Jr. 1977. The pariah: Its ecology and importance to the origin, development
and study of purebred dogs. Purebred Dogs: American Kennel Gazette 94: 22 - 29.
Brisbin, I. L. Jr. 1997. Primitive dogs, their ecology and behavior: Unique opportunities
12
to study the early development of the human-canine bond. Journal American Veterinary
Medical Association 210(8): 1122-1126.
Budiansky, S. 1999. The covenant of the wild: why animals chose domestication. Yale
Univ. Press, New Haven.
Bulmer, R. 1976. Selectivity in hunting and in disposal of animal bone by the Kalam of
the New Guinea Highlands. In Problems in economic and social archaeology. 169 – 186.
eds. G. de G. Sieveking, I. H. Longworth and K. E. Wilson. Duckworth, London.
Carr, S. M., S. W. Ballinger, J. N. Deer, L. H. Blankenship, and J. W. Bickham. 1986.
Mitochondrial DNA analysis of hybridization between sympatric white-tailed deer and
mule deer in west Texas. Proceedings National Academy of Sciences 83(9): 576 - 580.
Clutton-Brock, J. 1977. Man-made dogs. Science 197:1340-1342.
Clutton-Brock, J. 1981. Domesticated animals from early times. British Museum
(Natural History)/Heinemann, London.
Clutton-Brock, J. 1984. Dog. In Evolution of domestic animals. 198 – 211, ed. I. Mason.
Longman, London.
Clutton-Brock, J. 1994. The unnatural world: behavioral aspects of humans and animals
in the process of domestication. In Animals and human society: changing perspectives.
23 – 35, eds. A. Manning & J. Serpell. Routledge, London.
Clutton-Brock, J. 1995. Origins of the Dog: domestication and early history. In
The domestic dog: its evolution, behaviour and interactions with people. 7 – 20, ed. J.
Serpell. Cambridge University Press, NY.
Clutton-Brock, J. 1999. A natural history of domesticated animals. Cambridge
University Press, Cambridge.
Clutton-Brock, J., G. B. Corbet and M. Hills. 1976. A review of the family Canidae with
a classification by numerical methods. Bulletin British Museum (Natural History)
Zoology 29: 117 B 119.
Clutton-Brock, J., A. C. Kitchener & J. M. Lynch. 1994. Changes in the skull
morphology of the Arctic wolf, Canis lupus arctos, during the twentieth century. Journal
of Zoology 233: 19 - 36.
Coe, S. 1994. The basenji, out of Africa to you. Doral Publishers, Wilsonville, Oregon,
USA.
Cohn, J. 1997 How wild wolves became domestic dogs. BioScience 47: 725 B728.
13
Coppinger, R. and L. Coppinger. 2001. Dogs: a startling new understanding of canine
origin, behavior and evolution. Scribner, NY.
Coppinger, R. P. and C. K. Smith. 1983. The domestication of evolution. Environmental
Conservation 10(4): 283 – 292
Coppinger, R. and R. Schneider. 1995. Evolution of working dogs. In The domestic dog:
its evolution, behaviour and interactions with people. 21 –47. ed. J. Serpell. Cambridge
University Press, Cambridge, UK.
Corbet, G. B. and J. E. Hill. 1992. The Mammals of the Indomalayan Region: a
systematic review. Oxford University Press, Oxford.
Corbett, L. 1995. The dingo in Australia and Asia. Cornell Univ. Press, NY.
Crisler, L. 1958. Arctic wild. Harper and Brothers, New York.
Crockford, S.J. 2000. A commentary on dog evolution: regional variation, breed
development and hybridization with wolves. In Dogs through time: an archaeological
perspective. 295 – 312, ed. S. J. Crockford. BAR International Series 889. Archaeopress,
Oxford.
Cronin, M. A. 1993. Mitochondrial DNA in wildlife taxonomy and conservation
biology: cautionary notes. Wildlife Society Bulletin 21: 339 - 448.
Cronin, M. A., E. R. Vyse and D. G. Cameron. 1988. Genetic relationships
between mule deer and white-tailed deer in Montana. Journal Wildlife Management 52:
320-328.
Cronin, M. A., S. C. Amstrup, G. Garner and E. R. Vyse. 1991. Intra- and interspecific
mitochondrial DNA variation in North American bears (Ursus). Canadian Journal of
Zoology 69: 2,985 – 2,992.
Dahr, E. 1942. Arkiv for zoologie (Stockholm). 33A: 1 – 56. (Cited in Manwell and
Baker 1983.)
Darwin, C. 1875. The variation of animals and plants under domestication. 2nd.
ed. Vol. 1. John Murray, London.
Davis, S. J. 1987. The archaeology of animals. Yale University Press, New Haven.
Degerbøl, M. 1961. On a find of a preboreal domestic dog from Starr Carr, Yorkshire,
with remarks on other Mesolithic dogs. Proceedings Prehistorical Society 27: 35 - 55.
14
Endo, H., I. Obara, T. Yoshida, M. Kurohmaru, Y. Hayashi, and N. Suzuki. 1997.
Osteometrical and CT examination of the Japanese wolf skull. Journal of Veterinary
Medical Science 59(7): 531-538.
Epstein, H. 1971. The origin of the domestic animals of Africa. Vol. 1, Africana
Publishing Corp., N.Y.
Ewer, R. F. 1973. The carnivores. Cornell University Press, Ithaca, NY.
Fox, M. W. 1971. Behavior of wolves, dogs and related Canids. Robert E. Krieger
Publishing Company, Malabar, Florida, USA.
Fox, M. W. 1973. Origin of the dog and effects of domestication. American Kennel Club
Gazette 90(7): 33 -35.
Fox, M. W. 1984. The whistling hunters: field studies of the Asiatic wild dog (Cuon
alpinus). State University of New York Press, NY.
Frank, F. and M. Frank. 1983. Inhibition training in wolves and dogs. Behavioural
Processes 8: 363 B 377.
Frank, F. and M. Frank. 1987. The University of Michigan canine information-processing
project (1979-1981). In Man and wolf. 143 – 167, ed. H. Frank. Dr. W. Junk Publishers,
Dordrecht, the Netherlands.
Gier, H. T. 1975. Ecology and behavior of the coyote (Canis latrans). In The wild
canids: their systematics, behavioral ecology and evolution. 247-262, ed. M. Fox.
Van Nostrand Reinhold, NY.
Ginsberg, J. R. and D. W. Macdonald. 1990. Foxes, wolves, jackals, and dogs: an
action plan for the conservation of canids. IUCN/SSC Canid Specialist Group/Wolf
Specialist Group, Oxford.
Gloyd, J. S. 1992. Wolf hybrids: A Biological time bomb? Journal of the American
Veterinary Medical Association 210: 381-382.
Gollan, K. 1982. The prehistoric dingo. Ph.D. thesis. Australian National University,
Canberra.
Goodman, P. A. and E. Klinghammer. 1990. Wolf ethogram. Ethology Series Number 3,
revised. North American Wildlife Park Foundation, Battle Ground, Indiana, USA.
Gottelli, D., C. Sillero-Zubiri, G. D. Applebaum, M.S. Roy, D. J. Girman, J. Garcia-
Moreno, E. Ostrander and R. K. Wayne. 1994. Molecular genetics of the most
endangered canid: the Ethiopian wolf. Molecular Ecology 3: 301-312.
15
Gould, S. J. 1977. Ontogeny and phylogeny. Harvard University Press, Cambridge,
Massachusetts, USA.
Gowlett, J. A. J. 1993. Ascent to civilization: an archaeology of early humans. 2nd ed.
McGraw-Hill, Inc., NY.
Hamilton-Smith, C. 1839. Dogs. Vol. 1. In Naturalists Library. ed. W. Jardine. Lizars,
Edinburgh.
Harrison, D. L. 1973. Some comparative features of the skulls of wolves (Canis lupus
Linn.) and pariah dogs (Canis familiaris Linn.) from the Arabian peninsula and
neighboring lands. Bonner Zoologische Beiter, Herausgeber, Zooloisches
Forschungsintitut und Museum Alexander Koenig, Bonner (24): 185 – 191.
Harrison, D. L. and P. J. J. Bates. 1991. The mammals of Arabia. 2nd ed. Harrison
Zoological Museum Publication,
Hayden, B. 1975. Dingoes: pets or producers? Mankind 8: 287 – 295.
Hemmer, H. 1990. Domestication: the decline of environmental appreciation. Cambridge
Univ. Press., NY.
Higham, C. F. W., A. Kijngam and B. F. J. Manly. 1980. An analysis of prehistoric canid
remains from Thailand. Journal of Archaeological Science 7: 149-165.
Hildebrand, M. 1954. Comparative morphology of the body skeleton in recent canidae.
University of California Press, Berkeley.
Hope, J. 1994. Wolves and wolf hybrids as pets are big business - but a bad idea.
Smithsonian 25(3): 40 - 43.
Hu, C. & T. Qi. 1978. Gongwangling Pleistocene mammalian fauna of Lantian, Shaanxi.
Paleontologia Sinica, Whole Series no. 155, New Series C no. 21, 64 pages. Bejing.
(Cited in S. Olsen 1985)
Jones, K. T. 1993. The archaeological structure of a short-term camp. In From bones to
behavior: ethnoarchaeological and experimental contributions to the interpretation of
faunal remains. 101- 114, ed. J. Hudson. Center for Archaeological Investigations.
Occasional Paper No. 21. Southern Illinois University, Carbondale.
Kahlke, H. D. & B.- S. Chow. 1961. A summary of stratigraphical and paleontological
observations in the lower layers of Choukoutien, Locality 1 and on the chronological
position of the site (in Chinese). Vertebrata PalAsiatica, 3: 212-240. (Cited in Olsen
1985.)
Kieser, J. A. and H. T. Groeneveld. 1992. Comparative morphology of the
16
mandibulodental complex in wild and domestic canids. Journal of Anatomy 180: 419-
424.
Kleiman, D. G. 1967. Some aspects of social behavior in the Canidae. American
Zoologist 7: 365 - 372.
Kleiman, D. G. & C. A. Brady. 1978. Coyote behavior in the context of recent canid
research: problems and perspectives. In Coyotes: biology, behavior and management 163
– 188, ed. M.(arc) Bekoff. Academic Press, NY.
Klinghammer, E. and P. A. Goodman. 1985. The management and socialization of
captive wolves (Canis lupus) at Wolf Park. North American Wildlife Park Foundation,
Battle Ground, Indiana, USA.
Koler-Matznick, J., I. L. Brisbin, Jr. & J. MacIntyre. 2000. The New Guinea singing
dog: A living primitive dog. In Dogs through time: an archaeological perspective. 239-
247, ed. S. J. Crockford. BAR International Series 889. Archaeopress, Oxford.
Koler-Matznick, J., I. L. Brisbin, Jr. & M. Feinstein. 2001. An ethogram of the New
Guinea singing dog (Canis hallstromi). New Guinea Singing Dog Conservation Society,
Central Point, Oregon, USA.
Koop, B. F., M. Burbidge, A. Byun, U. Rink & S. J. Crockford. 2000. Ancient DNA
evidence of a separate origin for North American indigenous dogs. In Dogs through time:
an archaeological perspective. 271 – 286, ed. S. J. Crockford. BAR International Series
889. Archaeopress, Oxford.
Kumar, S. 2001. Wolves in India: compensation policies complicate wolf depredation
conflicts. International Wolf. 1(3): 8 – 9.
Lauer, B. H., E. Kuyt and B. E. Baker. 1969. Arctic wolf (Canis lupus arctos) and husky
milk: gross composition and fatty acid constitution. Canadian Journal of Zoology 47: 99
– 102.
Lawrence, B. 1967. Early domestic dogs. Zeitschrift für Säugetierkunde 32: 44 – 59.
Leone, C. A. and A. L. Wiens. 1956. Comparative serology of carnivores. Journal of
Mammalogy 37:11 – 23.
Lorenz, K. 1954. Man meets dog. Methuen, London.
Macintosh, N.W.G. 1975. The origin of the dingo: an enigma. In The wild canids: their
systematics, behavioral ecology and evolution. 87 – 106, ed. M. Fox.
Van Nostrand Reinhold, NY.
Manwell, C. & C. M. A. Baker. 1983. Origin of the dog: from wolf or wild Canis
17
familiaris? Speculations in Science and Technology 6 (3): 213-224.
Manwell, C. and C. M. Baker. 1984. Domestication of the dog: hunter, food, bed-warmer,
or emotional object? Zeitschrift für Tierzüchtung und Züchtunsbiologie – Journal of
Animal Breeding and Genetics 101 (4): 241-256 1984
Marx, D. 1994. Wolf hybrids: to own or not to own? Dog World 79: 42 - 45.
Mech, L. D. 1970. The wolf: ecology and behavior of an endangered species.
Doubleday, NY.
Mech, L. D. 1996. Wolves and 'child lifting' in India. International Wolf 6(4): 16.
Mech, L. D. 1998. Who's afraid of the big bad wolf? International Wolf 8(1): 8 – 11.
Meggitt, M. J. 1958. The Enga of the New Guinea highlands: some preliminary
observations. Oceania 28(4): 253 - 330.
Meggitt, M. J. 1965. The association between Australian aboriginies and dingoes. In
Man, culture and animals. 7 – 26, eds. A. Leeds and A. P. Vayda. American Association
for the Advancement of Science, Washington, DC.
Morey, D. F. 1990. Cranial allometry and the evolution of the domestic dog. Ph. D.
Thesis. University of Tennessee, Knoxville, USA.
Morey, D. F. 1992. Size, shape and development in the evolution of the domestic dog.
Journal of Archaeological Science 19: 181 - 204.
Nowak, R. M. 1979. North American Quaternary Canis. Monograph 6. Museum of
Natural History, University of Kansas, Lawrence, Kansas, USA.
Nowak, R. M. 1995. Hybridization: the double-edged threat. Canid News 3: 2-6.
O'Brien, S. J. and E. Mayr. 1991. Bureaucratic mischief: recognizing endangered species
and subspecies. Science 251: 1187-1188.
Okumura, N., N. Nakano, N. Ishiguro, A. Matsui and M. Sahara. 1996. Intra- and
interbreed genetic variations of mitochondrial DNA major non-coding regions in
Japanese native dog breeds (Canis familiaris). Animal Genetics 27:397-405.
Oliver, J. S. 1993. Carcass processing by the Hadza: bone breakage from butchery
consumption. In From bones to behavior: ethnoarchaeological and experimental
contributions to the interpretation of faunal remains. 200 – 227, ed. J. Hudson. Center for
Archaeological Investigations Occasional Paper No. 21, Southern Illinois University at
Carbondale, USA.
18
Olsen, S. J. 1985. Origins of the domestic dog: the fossil record. Univ. of Arizona Press,
Tucson, USA.
Oppenheimer, E. & R. Oppenheimer. 1975. Certain behavioral features in the pariah dog
(Canis familiaris) in west Bengal. Applied Animal Ethology 2: 81 - 92.
Ovodov, N. D. 1998. The ancient dog of Siberia. Abstract. 223. Final program and
abstracts. 8th International Congress of the International Council for Archaeozoology
(Becky Wigen, Chair, Organizing Committee). University of Victoria, Canada.
Pal, S. K., B. Gosh and S. Roy. 1998. Agonistic behaviour of free-ranging dogs (Canis
familiaris) in relation to season, sex and age. Applied Animal Behaviour Science 59:
331-348.
Pei, W. C. 1934. The carnivora from locality 1 of Choukoutien. Palaeontologia Sinica,
Series C, vol. 8, Fascicle 1, Geological Survey of China, Bejing.
Randi, E. and V. Lucchini. 2002. Detecting rare introgression of domestic dog genes into
wild wolf (Canis lupus) populations by Bayesian admixture analyses of microsatellite
variation. Conservation Genetics 3(1): 29 – 43.
Scott, J. P. and J. Fuller. 1965. Genetics and the social behavior of dogs. University of
Chicago Press, Chicago.
Shahi, S. P. 1983. Status of the gray wolf in India. Acta Zoologica Fennica 174: 283-286.
Steinhart, P. 1995. The company of wolves. Vintage Books, New York.
Stewart, P. 1993. Mapping the dhole. Canid News 1: 18-21.
Stockhaus, K. 1965. Metrische Untersuchungen an Schudlen von Wolfen und Hunden,
Zeitschrift fur Zoologishe Systematik und Evolutionsforschung 3: 157 B 258.
Sullivan, J. O. 1978. Variability in the wolf, a group hunter. In Wolf and man: evolution
in parallel. 31 – 40. eds. R. L. Hall. and H. S. Sharp. Academic Press, NY.
Tchernov, E. and L. K. Horowitz. 1991. Body size diminution under domestication:
unconscious selection in primeval domesticants. Journal of Anthropological Archaeology
10: 54 – 75.
Teilhard de Chardin, P. and J. Piveteau. 1930. Les mammifères fossiles de Nihowan
(Chine). Annales de Paleontologie, T. XIX, Paris. (Cited in Pei 1934)
Titcomb, M. 1969. Dog and man in the ancient pacific with special attention to
Hawaii. Bernice P. Bishop Museum Special Publication 59. Honolulu, Hawaii, USA.
19
Tsuda, K., Y. Kikkawa, H. Yonekawa and Y. Tanabe. 1997. Extensive
interbreeding occurred among multiple matriarchal ancestors during the domestication of
dogs: Evidence from inter- and intraspecies polymorphisms in the D-loop region of
mitochondrial DNA between dogs and wolves. Genes, Genetics and Systematics 72: 229
- 238.
Vilà,C., P. Savolainen, J. E. Maldonado, I. R. Amorim, J. E. Rice, R. L.
Honeycutt, K. A. Crandall, J. Ludeburg, R. K. Wayne. 1997. Multiple and Ancient
Origins of the Dog. Science 276: 1687-1689.
Vilà, C. and R. K. Wayne. 1999. Hybridization between wolves and dogs. Conservation
Biology 13 (1): 195-198.
Walker, D. N. & G. C. Frison. 1982. Studies on Amerindian dogs, 3: prehistoric wolf/dog
hybrids from the Northwestern plains. Journal of Archaeological Science 9: 125 - 172.
Wayne, R. K. 1986. Cranial morphology of domestic and wild canids: the influence of
development on morphological change. Journal of Morphology 187: 301 - 319.
Wayne. R. K. and S. J. O'Brien. 1987. Allozyme divergence within the Canidae.
Systematic Zoology 36: 339-355.
Wayne, R. K., B. Van Valkenburgh and S. J. O'Brien. 1991. Molecular distance and
divergence time in carnivores and primates. Molecular & Biological Evolution 8(3): 297-
319.
Wayne, R. K., N. Lehman, M. W. Allard and R. Honeycutt. 1991. Mitochondrial DNA
variability of the gray wolf: genetic consequences of population decline and habitat
fragmentation. Conservation Biology 6(4): 559 – 569.
Wayne, R. K. and E. A. Ostrander. 1999. Origin, genetic diversity, and genomic structure
of the domestic dog. BioEssays 21: 247-257.
Wilson , D. E. & D. M. Reeder. 1993. Mammal species of the world: a taxonomic and
geographic reference. Smithsonian Inst. Press, Washington, DC.
Wolpoff, M. and R. Caspari, 1997. Race and human evolution. Simon & Schuster, NY.
Zdansky, O. 1925. Quartäre Carnivoren aus Nord-China. Palaeontologia Sinica Series C,
Vol. II, Fascicle 2, pp. 1 – 38. (Cited in Pei 1934)
Zeuner, F. E. 1963. A history of domesticated animals. Harper and Row, NY.
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Appendix I.
Aboriginal dogs: Autochthonous ancient races of DDs associated with indigenous
cultures.
Dog: Canids that are not wolves, jackals, or foxes: namely Canis familiaris, Canis dingo
(Australian dingo), Canis hallstromi (New Guinea singing dog).
Domesticated dog: A population whose reproduction has been under human control for
many generations, with artificial selection.
Pariah dogs: Free-ranging, free-breeding semi-domesticated dogs commensal with
humans: scavenger ecological niche.
Primitive dogs: Populations that approximate wild Canis morphology, with no
derived characters such as pendant ears, and which have not, as far as is known,
been subjected to controlled breeding. Examples: dingo, New Guinea singing dog.
Proto-domestic dogs: Tamed wild canids utilizing commensal scavenger niche.
Wild dogs: Populations mainly utilizing predator niche, subsisting without any
dependency upon humans or human wastes.
Wolf: gray wolf, Canis lupus.