CANINES and FELINES

Under construction May 2011

CANINES AND FELINES

ORDER CARNIVORA (the carnivores)

Family Canidae (the canids)

Arctic Fox (Alopex lagopus)

Coyote (Canis latrans incolatus)

Dog (Canis lupus familiaris)

Red Fox (Vulpes vulpes)

Wolf (Canis lupus)

LENGTH: Coyote, dog, and wolf had a lot of variability in guard hair length (up to 120-150mm), but the arctic fox and red fox seemed to have a maximum length around 80 or 85mm.

WIDTH: Maximum width of guard hair is usually less than 200 microns.  If it is greater than 200 microns, the maximum length of the shaft is less than 15mm according to Mayer (1952)  In our research, coyote, dog and wolf might be up to 228 microns.

MEDULLA: Canids almost always have a medulla, exceptions perhaps being the one paw pad hair on a wolf we sampled and some individual dog hairs in a larger sample of hairs that did have a medulla in other hairs from that sample.  Often the medulla is too dark to show any features.  The edges of the medulla where it meets the cortex are usually smooth without a lot of features such as lumps or finger-like shapes, as we see in some rodents and weasels.   The cells in fox medulla, both red and arctic, are often visible.  Fox medulla seems to be distinguished by an undulating S-shape that makes its way between the cells of the medulla, which often look like alternating stacked wedge-shaped or teardrop-shaped cells one or two across, but sometimes up to three across the width of the medulla.

MEDULLARY INDEX: Generally 0.45 to 0.74, medullary index of the guard hair is not very useful to distinguish between the canines.  However, the medullary index of the underfur may be a clue.  It is rarely less than 0.4 except on dog and coyote when underfur medulla tends to be quite narrow.

SCALE: The typical canid scale pattern on the guard hair seems to change along the length of the shaft in a predictable pattern: long pointy petal shapes near the base, then becoming fatter petals with smooth edges and then changing to mosaic tile shaped scales with wavy edges in the mid-shaft region with scale margins gradually getting a torn-paper edge and becoming ever closer together near the tip.  Intermediate hairs, such as the ones on the arctic fox, can show a pointy-petal shaped scale pattern for the entire length.  Raccoon fur, which might look like a canid hair, lacks the petal-shaped scales at the base.  Kennedy (1982) seems to think that the scale pattern near the base is chevron-like on wolves and coyotes, coronal on red foxes, and dentate on domestic dogs. 

COLOR: Banding is important on canid hair and may be the distinguishing feature between coyote and wolf.  Both have a dark tip followed by a white band.  In the coyote, that band ought to be less than 15mm long.  In the wolf, the white band can be up to 36mm. 

UNDERFUR: Foxes tend to have shorter underfur than wolves and coyotes, in the 15-50mm range.  Coyotes are in the 35-50mm range, and underfur longer than 50 may suggest wolf.  Common uniserial ladder medulla and stacked crown scales of the underfur don’t help differentiate between the canids, but narrower medulla on dog and coyote might?

SUMMARY: You ought to be able to nail down fox versus other canids, and use banding to distinguish coyote from wolf.  But distinguishing dog from coyote or wolf may be tricky.  Kennedy’s 1982 paper on the guard hairs of Alberta canids claims that wolf and coyote are hard to distinguish.  Many published references seem to have an over-reliance on banding to distinguish dog hair.  More study of bear scale patterns are needed, but might be similar to canid with smooth scale margins at base and rougher ones near tip.  Bears and canids have close taxonomic relationships in other ways as well.

Family Felidae  (the felines)

Lynx (Lynx Canadensis)

LENGTH: Guard hairs tend to be long, often over 50mm

WIDTH: Huge variation in reported width, up to 184 microns, but closer to 100 is more typical.

MEDULLA: The bulbous cells in the medulla at max shaft diameter are supposedly most diagnostic but not always easy to see.  They also occur in red fox, but are smaller there.  (Mayer 1952) Adorjan and Kolenosky (1969) provide comparative data about other cats.  Ought to be able to see balls of pigment in medulla in some areas.

MEDULLARY INDEX: Fairly wide medulla, index 0.63 – 0.87

SCALE: Scales change along the length of the hair, with base end scales 2-3 across with smooth edges and widely spaced. No diamond petal shapes like we see in canids.  Towards the distal end of the fiber the scales are more irregular, closer spaced and have rougher margins.

UNDERFUR: Typical wide uniserial ladder and stacked crowns.  Usually in the 20-40mm range.  Pale.

COLOR: Banding often seen on lynx, but can be variable.  ASM samples indicated the middle band is lighter with darker base and tip bands.  Differs from canids and raccoons by a much weaker development of the second dark band according to Mayer (1952)

SUMMARY: Look for long guard hair, banding, wide medulla in guard hairs and underfur.

 

Comparative photos of guard hair scale casts below:

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