Canidae

Canids[1] Fossil range: 39.75–0 Ma PreЄ Є O S D C P T J K Pg N Late Eocene - Recent
Gray Wolf (Canis lupus)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Suborder: Caniformia Family: Canidae G. Fischer de Waldheim, 1817
Genera and species
See text

Canidae (pronounced /ˈkænɨdiː/ or /ˈkeɪnɨdiː/^[2]) is the biological family of the dogs; a member of this family is called a canid (/ˈkeɪnɨd/). They include wolves, foxes, coyotes, and jackals. The Canidae family is divided into the "true dogs" of the tribe Canini and the "foxes" of the tribe Vulpini. The two species of the basal Caninae are more primitive and do not fit into either tribe.

Classification and relationship

The subdivision of Canidae into "foxes" and "true dogs" may not be in accordance with the actual relations; also the taxonomic classification of several canines is disputed. Recent DNA analysis shows that Canini (dogs) and Vulpini (foxes) are valid clades. (See phylogeny below). Molecular data implies a North American origin of living Canidae and an African origin of wolf-like canines (Canis, Cuon, and Lycaon).^[3]

Currently, the domestic dog is listed as a subspecies of Canis lupus, C. l. familiaris, and the Dingo (also considered a domestic dog) as C. l. dingo, provisionally a separate subspecies from C. l. familiaris; the Red Wolf, Eastern Canadian Wolf, and Indian Wolf are recognized as subspecies.^[1] Many sources list the domestic dog as Canis familiaris, but others, including the Smithsonian Institution and the American Society of Mammalogists, more precisely list it as a subspecies of C. l. familiaris; the Red Wolf, Eastern Canadian Wolf, and Indian Wolf may or may not be separate species; the Dingo has been in the past variously classified as Canis dingo, Canis familiaris dingo and Canis lupus familiaris dingo.

Evolution

Eocene epoch

Carnivorans evolved from miacoids about 55 million years ago during the late Paleocene.^[4] Then, about 50 million years ago, the carnivorans split into two main divisions: caniforms (dog-like) and feliforms (cat-like). By 40 million years ago the first clearly identifiable member of the dog family Canidae had arisen. It was called Prohesperocyon wilsoni and was found in what is now southwestern Texas. This fossil species bears a combination of features that definitively mark it as a canid: teeth that include the loss of the upper third molar (a general trend toward a more shearing bite), and the characteristically enlarged bony bulla (the rounded covering over the middle ear). Based on what we know about its descendants, Prohesperocyon likely had slightly more elongated limbs than its predecessors, along with toes that were parallel and closely touching, rather than splayed, as in bears.^[5]

The Canidae family soon subdivided into three subfamilies, each of which diverged during the Eocene: Hesperocyoninae (~39.74-15 Mya), Borophaginae (~36-2 Mya), and the Caninae lineage that led to present-day canids (wolves, foxes, coyotes, jackals, and domestic dogs). Each of these groups showed an increase in body mass with time, and sometimes exhibited a specialised hypercarnivorous diet that made them prone to extinction.^{[6]:Fig. 1} Only the Caninae lineage, commonly referred to as "canines," survived to the present day.

Oligocene epoch

The earliest branch of the Canidae was the Hesperocyoninae lineage, which included the coyote-sized Mesocyon of the Oligocene (38-24 Mya). These early canids probably evolved for fast pursuit of prey in a grassland habitat, and resembled modern civets in appearance. Hesperocyonines became extinct except for the Nothocyon and Leptocyon branches. These branches led to the borophagine and canine radiations.^[7]

Miocene epoch

Around 9-10 Mya during the Late Miocene, Canis, Urocyon, and Vulpes genera expanded from southwestern North America. This was the point where the canine radiation began. The success of the these canines was related to the development of lower carnassials that were capable of both mastication and shearing. Around 8 Mya, Beringia offered the canines a way to enter Eurasia.

Early Pliocene

During the Pliocene around (4-5 Mya) Canis lepophagus appeared in North America. This was small and sometimes coyote-like. Others were wolf-like in characteristics. It is theorized that Canis latrans (the coyote) descended from Canis lepophagus.^[8] Around 1.5 to 1.8 Mya, a variety of wolves were present in Europe. Also, the North American wolf line appeared with Canis edwardii, clearly identifiable as a wolf. Canis rufus appeared, possibly a direct descendent of Canis edwardii.

Middle Pliocene

Around 0.8 Mya Canis ambrusteri, emerged in North America. A large wolf, it was found all over the continent. It is thought that this species migrated to South America where it became the ancestor of Canis dirus, the dire wolf.

Late Pliocene

At 0.3 Mya Canis lupus (the gray wolf) was fully developed and had spread throughout Europe and northern Asia. Berengia offered a way to North America.^[9] At around 100,000 years ago, the dire wolf, one of the largest members of the dog family, had spread from South America to southern Canada and from coast to coast. The dire wolf shared its habitat with the gray wolf. Around 8000 years ago the dire wolf became extinct.

Characteristics

Wild canids are found on every continent except Antarctica, and inhabit a wide range of different habitats, including deserts, mountains, forests, and grassland. They vary in size from the Fennec Fox at 24 cm long, to the Gray Wolf, which may be up to 2 m long, and can weigh up to 80 kg.

With the exceptions of the Bush Dog and Raccoon Dog, canids have relatively long legs and lithe bodies, adapted for chasing prey. All canids are digitigrade, meaning that they walk on their toes. They possess bushy tails, non-retractile claws, and a dewclaw on the front feet. They possess a baculum, which together with a cavernous body helps to create a copulatory tie during mating, locking the animals together for up to an hour. Young canids are born blind, with their eyes opening a few weeks after birth. ^[10]

Social behavior

Gray wolf pack hunting an American bison in Yellowstone National Park.

Almost all canids are social animals and live together in groups. In most foxes and in many of the true dogs, a male and female pair work together to hunt and to raise their young. Gray wolves and some of the other larger canids live in larger groups called packs. African wild dogs have the largest packs, which can number as many as 90 animals. Some species form packs or live in small family groups depending on the circumstances, including the type of available food. In most species, there are also some individuals who live on their own. Within a canid pack, there is a system of dominance so that the strongest, most experienced animals lead the pack. In most cases, the dominant male and female are the only pack members to breed.

Canids communicate with each other by scent signals, by visual clues and gestures, and by vocalizations such as growls, barks, and howls. In most cases, groups have a home territory from which they drive out others. The territory is marked by leaving urine scent marks, which warn trespassing individuals.^[11]

Most canids bear young once a year, from 1 to 16 or more (in the case of the African wild dog) at a time. The young are born small and helpless and require a long period of care. They are kept in a den, most often dug into the ground, for warmth and protection. When they begin eating solid food, both parents, and often other pack members, bring food back for them from the hunt. This is most often vomited up from the adult's stomach. Young canids may take a year to mature and learn the skills they need to survive.^[12]

Dentition

Most canids have 42 teeth, with a dental formula of:

As in other members of Carnivora, the upper fourth premolar and lower first molar are adapted as carnassial teeth for slicing flesh. The molar teeth are strong in most species, allowing the animals to crack open bone to reach the marrow. The deciduous or baby teeth formula in canids is 3 1 3; molars are completely absent.

Canids and humans

Traditional English fox hunt

One canid, the domestic dog, long ago entered into a partnership with humans and today remains one of the most widely kept domestic animals in the world and serves humanity in a great many important ways. Most experts believe the domestic dog is descended from an Asian subspecies of the Gray Wolf.

Among canids, only the gray wolf has been known to prey on humans.^[13] There is at least one record of a coyote killing a toddler,^[14] and two of golden jackals killing children.^[15] Some canid species have also been trapped and hunted for their fur and, especially the Gray Wolf and the Red Fox, for sport. Some canids are now endangered in the wild due to hunting, habitat loss, and the introduction of diseases from domestic dogs.^[16]

Species and taxonomy

Coyote

African Hunting Dog

Red Fox

Red Wolf

Dhole

Golden Jackal

Bat-eared Fox

Gray Fox

Maned Wolf

Short-eared Dog

Pampas Fox

Arctic Fox

Raccoon Dog

A modern domesticated West Highland White Terrier

FAMILY CANIDAE

Subfamily: Caninae

• True dogs - Tribe Canini
  • Genus Canis
    • Side-striped Jackal, Canis adustus
    • Golden Jackal, Canis aureus
    • Himalayan Wolf, Canis himalayensis (sometimes considered as gray wolf species)
    • Indian Wolf, Canis indica (sometimes considered as gray wolf species)
    • Coyote, Canis latrans (also called Prairie Wolf)
    • Deeb, Canis lupaster
    • Gray Wolf, Canis lupus (2.723 Ma to present)
      • Domestic Dog, Canis lupus familiaris
      • Dingo, most often classified as Canis lupus dingo (sometimes considered a separate taxon)
      • New Guinea Singing Dog, Canis lupus hallstromi
      • many other proposed subspecies
    • Red Wolf, Canis rufus (3 Ma to present)
      • Eastern Wolf, Canis (rufus) lycaon (sometimes considered a separate species)
    • Black-backed Jackal, Canis mesomelas
    • Ethiopian Wolf, Canis simensis (also called Abyssinian Wolf, Simien Fox and Simien Jackal)
  • Genus Cuon
    • Dhole, Cuon alpinus or Canis alpinus (also called Asian Wild Dog)
  • Genus Lycaon
    • African Wild Dog, Lycaon pictus (also called African Hunting Dog)
  • Genus Atelocynus
    • Short-eared Dog, Atelocynus microtis
  • Genus Cerdocyon
    • Crab-eating Fox, Cerdocyon thous
  • Genus Dasycyon † ?
    • Hagenbeck Wolf, Dasycyon hagenbecki † ?
  • Genus Dusicyon †
    • Falkland Island Fox, Dusicyon australis †
  • Genus Pseudalopex
    • Culpeo, Pseudalopex culpaeus
    • Darwin's Fox, Pseudalopex fulvipes
    • Argentine Grey Fox, Pseudalopex griseus
    • Pampas Fox, Pseudalopex gymnocercus
    • Sechura Fox, Pseudalopex sechurae
    • Hoary Fox, Pseudalopex vetulus
    • Mendoza Fox, Pseudalopex sp.?
  • Genus Chrysocyon
    • Maned Wolf, Chrysocyon brachyurus
  • Genus Speothos
    • Bush Dog, Speothos venaticus
    • Unnamed bush dog relative, Speothos pacivorus †

• True foxes - Tribe Vulpini
  • Genus Vulpes
    • Arctic Fox, Vulpes lagopus
    • Red Fox, Vulpes vulpes (1 Ma to present)
    • Swift Fox, Vulpes velox
    • Kit Fox, Vulpes macrotis
    • Corsac Fox, Vulpes corsac
    • Cape Fox, Vulpes chama
    • Pale Fox, Vulpes pallida
    • Bengal Fox, Vulpes bengalensis
    • Tibetan Sand Fox, Vulpes ferrilata
    • Blanford's Fox, Vulpes cana
    • Rüppell's Fox, Vulpes rueppelli
    • Fennec Fox, Vulpes zerda
  • Genus Urocyon (2 Ma to present)
    • Gray Fox, U. cinereoargenteus
    • Island Fox, U. littoralis
    • Cozumel Fox, U. sp.

• Basal Caninae
  • Genus Otocyon (probably a vulpine close to Urocyon)
    • Bat-eared Fox, Otocyon megalotis
  • Genus Nyctereutes
    • Raccoon Dog, Nyctereutes procyonoides

Fossil Canidae

Classification of Hesperocyoninae from Wang (1994)^[17] and Borophaginae from Wang et al. (1999),^[18] except where noted.

Prehistoric Caninae

• Canini
  • Genus Canis
    • Dire Wolf, Canis dirus (1 Ma †)
    • Canis arnensis (3.4 Ma, †)
    • Canis (Eucyon) cipio (8.2 Ma †, probably first species of Canis genus)
    • Canis etruscus (3.4 Ma †)
    • Canis mosbachensis (0.787 Ma †)
    • Canis lepophagus (4-5 Ma †)
    • Canis donnezani (4.0-3.1 Ma †, probably ancestor of wolves)
    • Canis edwardii (1.8 Ma †, first species of wolf in North America)
    • Canis gezi †
    • Canis nehringi †
    • Canis ameghinoi †
    • Canis michauxi †
    • Canis adoxus †
    • Canis cautleyi †
    • Canis armbrusteri (0.8 Ma †)
  • Genus Indocyon†
    • Indian Mute Dog, Indocyon caribensis † (also called Caribbean Dog)
  • Genus Cubacyon
    • Cuban Dhole, Cubacyon transversidens †
  • Genus Xenocyon
    • Xenocyon lycaonoides†
  • Genus Cynotherium †
    • Sardinian Dhole, Cynotherium sardous †
  • Genus Theriodictis (1.8 Ma †)
    • Theriodictis platensis (1.8 Ma †)
    • Theriodictis tarijensis (1.8 Ma †)
    • Theriodictis (Canis) proplatensis (2.1 Ma † )
  • Genus Protocyon †
    • Protocyon orcesi †
    • Protocyon scagliarum †
    • Protocyon troglodytes †
  • Genus Dusicyon †
    • Dusicyon avus †
  • Genus Cerdocyon
    • Cerdocyon avius †
    • Cerdocyon ensenadensis †
  • Genus Speothos
    • Speothos pacivorus †
  • Genus Nurocyon
    • Nurocyon chonokhariensis †
  • Genus Xenocyon
    • Xenocyon falconeri (2.6 Ma †)
    • Xenocyon lycaonoides

• Vulpini
  • Genus Vulpes (7 Ma to present)
    • Vulpes alopecoides (2.6 Ma †)
    • Vulpes cf. alopecoides (2.6 Ma †)
    • Vulpes cf. vulpes (0.1275 Ma †)
    • Vulpes galaticus (4.2 Ma †)
    • Vulpes riffautae (7 Ma †)
• Basal Canids
  • Genus Nyctereutes (7.1 Ma to present)
    • Nyctereutes cf. donnezani (7.1 Ma †)
    • Nyctereutes cf. megamastoides (3.158 Ma †)
    • Nyctereutes donnezani (3.4 Ma †)
    • Nyctereutes megamostoides (2.6 Ma †)
    • Nyctereutes sinensis (3.4 Ma †)

• First Caninae
  • Genus Eucyon (8 Ma †)
    • Eucyon davisi (8.3 Ma †, probably ancestor of Canis)
    • Eucyon minor (8 Ma †)
    • Eucyon zhoui (8 Ma †)
    • Eucyon monticinensis(8 Ma †)
    • Eucyon odessanus †
  • Genus Leptocyon (24-16 Ma †)
    • Leptocyon vafer (16 Ma)
    • Leptocyon vulpinus (24 Ma)

Borophaginae : † (Ma = million years ago)

• • Genus Aelurodon (16-12 Ma)
    • Aelurodon asthenostylus (16 Ma)
    • Aelurodon ferox (15 Ma)
    • Aelurodon mcgrewi (15 Ma)
    • Aelurodon montanensis (15 Ma)^[19]
    • Aelurodon stirtoni (13 Ma)
    • Aelurodon taxoides (12 Ma)
  • Genus Archaeocyon (32-24 Ma)
    • Archaeocyon falkenbachi (25-24 Ma)
    • Archaeocyon leptodus (32-24 Ma)
    • Archaeocyon pavidus (32-28 Ma)
  • Genus Borophagus (12-5 Ma)
    • Borophagus dividersidens (5 Ma)
    • Borophagus dudleyi
    • Borophagus hilli (6 Ma)
    • Borophagus littoralis (12 Ma)
    • Borophagus orc (9 Ma)
    • Borophagus parvus (7 Ma)
    • Borophagus pugnator (9 Ma)
    • Borophagus secundus (9 Ma)
  • Genus Carpocyon
    • Carpocyon compressus
    • Carpocyon limosus
    • Carpocyon robustus
    • Carpocyon webbi
  • Genus Cormocyon
    • Cormocyon copei
    • Cormocyon haydeni
  • Genus Cynarctoides (30-18 Ma)
    • Cynarctoides acridens (24 Ma)
    • Cynarctoides emryi (21 Ma)
    • Cynarctoides gawnae (18 Ma)
    • Cynarctoides harlowi (21 Ma)
    • Cynarctoides lemur (30 Ma)
    • Cynarctoides luskensis (21 Ma)
    • Cynarctoides roii (30 Ma)
  • Genus Cynarctus (16-12 Ma)
    • Cynarctus crucidens (12 Ma)
    • Cynarctus galushai (16 Ma)
    • ?Cynarctus marylandica
    • Cynarctus saxatilis (15 Ma)
    • Cynarctus voorhiesi (13 Ma)
  • Genus Desmocyon (24-19 Ma)
    • Desmocyon matthewi (19 Ma)
    • Desmocyon thompsoni (24 Ma)
  • Genus Epicyon (12-10 Ma)
    • Epicyon aelurodontoides (10.3-4.9 Ma)
    • Epicyon haydeni (10 Ma)
    • Epicyon saevus (12 Ma)
  • Genus Eulopocyon (18-16 Ma)
    • Eulopocyon brachygnathus (16 Ma)
    • Eulopocyon spissidens (18 Ma)
  • Genus Metatomarctus (19-16 Ma)
    • Metatomarctus canavus (19 Ma)
    • Metatomarctus sp. A (16 Ma)
    • Metatomarctus sp. B (16 Ma)
  • Genus Microtomarctus (18 Ma)
    • Microtomarctus conferta (18 Ma)
  • Genus Otarocyon (34-30 Ma)
    • Otarocyon cooki (30 Ma)
    • Otarocyon macdonaldi (34 Ma)
  • Genus Oxetocyon (32 Ma)
    • Oxetocyon cuspidatus (32 Ma)
  • Genus Paracynarctus (19-16 Ma)
    • Paracynarctus kelloggi (19 Ma)
    • Paracynarctus sinclairi (16 Ma)
  • Genus Paratomarctus (16-13 Ma)
    • Paratomarctus euthos (13 Ma)
    • Paratomarctus temerarius (16 Ma)
  • Genus Phlaocyon (30-19 Ma)
    • Phlaocyon achoros
    • Phlaocyon annectens (22 Ma)
    • Phlaocyon latidens (30 Ma)
    • Phlaocyon leucosteus (22 Ma)
    • Phlaocyon mariae
    • Phlaocyon marslandensis (19 Ma)
    • Phlaocyon minor (30 Ma)
    • Phlaocyon multicuspus
    • Phlaocyon taylori^[20]
    • Phlaocyon yakolai (19 Ma)
  • Genus Protepicyon (16 Ma)
    • Protepicyon raki (16 Ma)
  • Genus Protomarctus (18 Ma)
    • Protomarctus optatus (18 Ma)
  • Genus Psalidocyon (16 Ma)
    • Psalidocyon marianae (16 Ma)
  • Genus Rhizocyon (30 Ma)
    • Rhizocyon oregonensis (30 Ma)
  • Genus Tephrocyon (16 Ma)
    • Tephrocyon rurestris (16 Ma)
  • Genus Tomarctus (16 Ma)
    • Tomarctus brevirostris (16 Ma)
    • Tomarctus hippophaga (16 Ma)

Hesperocyoninae : † (Ma = million years ago)

• • Genus Cynodesmus (32-29 Ma)
    • Cynodesmus martini (29 Ma)
    • Cynodesmus thooides (32 Ma)
  • ?Genus Caedocyon
    • Caedocyon tedfordi
  • Genus Ectopocynus (32-19 Ma)
    • Ectopocynus antiquus (32 Ma)
    • Ectopocynus intermedius (29 Ma)
    • Ectopocynus siplicidens (19 Ma)
  • Genus Enhydrocyon (29-25 Ma)
    • Enhydrocyon basilatus (25 Ma)
    • Enhydrocyon crassidens (25 Ma)
    • Enhydrocyon pahinsintewkpa (29 Ma)
    • Enhydrocyon stenocephalus (29 Ma)
  • Genus Hesperocyon (39.74-34 Ma)
    • Hesperocyon coloradensis
    • Hesperocyon gregarius (37 Ma)
  • Genus Mesocyon (34-29 Ma)
    • Mesocyon brachyops (29 Ma)
    • Mesocyon coryphaeus (29 Ma)
    • Mesocyn temnodon
  • Genus Osbornodon (32-18 Ma)
    • Osbornodon brachypus
    • Osbornodon fricki (18 Ma)
    • Osbornodon iamonensis (21 Ma)
    • Osbornodon renjiei (33 Ma)
    • Osbornodon scitulus^[21]
    • Osbornodon sesnoni (32 Ma)
    • Osbornodon wangi^[20]
  • Genus Paraenhydrocyon (30-25 Ma)
    • Paraenhydrocyon josephi (30 Ma)
    • Paraenhydrocyon robustus (25 Ma)
    • Paraenhydrocyon wallovianus (26 Ma)
  • Genus Philotrox (29 Ma)
    • Philotrox condoni (29 Ma)
  • Genus Prohesperocyon (36 Ma)
    • Prohesperocyon wilsoni (36 Ma)
  • Genus Sunkahetanka (29 Ma)
    • Sunkahetanka geringensis (29 Ma)

See also

• Canine reproduction

Wikispecies has information related to: Canidae

Wikimedia Commons has media related to: Canidae

References

General references

Xiaoming Wang, Richard H. Tedford, Mauricio Antón, Dogs: Their Fossil Relatives and Evolutionary History, New York : Columbia University Press, 2008; ISBN 978-0-231-13528-3

External links

• African Wild Dog Conservancy