Journal of Threatened Taxa | www.threatenedtaxa.org | 26 August
2019 | 11(10): 14301–14308
The
identification of pika and hare through tricho-taxonomy (Mammalia: Lagomorpha)
Manokaran Kamalakannan
1, Kailash Chandra 2, Joy Krishna De 3 & Chinnadurai
Venkatraman 4
1,2,3,4 Zoological Survey of India, Prani Vigyan Bhawan, Block M, New Alipore, Kolkata, West
Bengal 700053, India.
1 kamalakannanm1@gmail.com
(corresponding author), 2 kailash611@rediffmail.com, 3 jkdezsi@gmail.com,
4 cvramanmbs@yahoo.com
Abstract: The macroscopic and microscopic characters of dorsal
guard hairs of Indian lagomorphs (four species of pikas
and three species of hare) are described; the cuticular and medullary
characters are similar between the species studied. The cuticular and medullary characters,
however, are dissimilar between the family Ochotonidae
and Leporidae. The cross-section of hair
of the species had shown two identical shapes
between the family Ochotonidae and Leporidae. The cross-section was observed as an oval
shape in all the four ochotonid species, whereas there was a dumb-bell shape in
all three leporid species. The hair of
the Indian lagomorphs can easily be differentiated up to the family level on
the basis of their unique cuticula, medulla and cross-section of the dorsal
guard hair. The high-resolution
microphotographs and key characteristics of hair that are presented here can be
used as an appropriate reference for family-level identification of Indian
lagomorphs.
Keywords:
Cuticular, dorsal guard hairs, lagomorphs, medullary character,
microphotographs.
doi: https://doi.org/10.11609/jott.4014.11.10.14301-14308
Editor:
Nishith Dhariaiya,
HNG University, Patan, India. Date of
publication: 26 August 2019 (online & print)
Manuscript
details: #4014 | Received 15
January 2018 | Final received 13 July 2019 | Finally accepted 31 July 2019
Citation: Kamalakannan, M., K. Chandra, J.K. De &
C. Venkatraman (2019). The identification of pika
and hare through tricho-taxonomy (Mammalia: Lagomorpha). Journal of Threatened Taxa 11(10): 14301–14308.
https://doi.org/10.11609/jott.4014.11.10.14301-14308
Copyright: © Kamalakannan et al. 2019. Creative Commons Attribution 4.0 International
License. JoTT
allows unrestricted use, reproduction, and distribution of this article in any
medium by adequate credit to the author(s) and the source of publication.
Funding: Ministry of Environment, Forest and Climate Change, Govt. of India.
Competing interests: The authors declare no competing interests.
Author
details: Dr. M. Kamalakannan is
specialized in mammal taxonomy; he is currently working as Senior Zoological
Assistant at the Mammal & Osteology Section of Zoological Survey of India,
Kolkata, India. His research interests lie on the taxonomic studies of mammal
components housed in the National Zoological Collections, ZSI. He also
specialized in identification of confiscated materials of mammals. He holds a
PhD in Zoology for working on the tricho-taxonomy of
Indian mammals. Dr. Kailash Chandra is currently the Director of Zoological
Survey of India under the Ministry of Environment, Forest and Climate Change,
Govt. of India. He has 37 years of research experience in the field of
zoological research with special reference to taxonomy. He has also described
several species and three genera of insects, new to science. Dr.
J.K. De, was a former Senior Scientist of Zoological Survey of India and
he was also served as a Scientific Officer at the West Bengal Zoo Authority,
Kolkata. He is expertise on tricho-taxonomy of Indian
mammals especially carnivores and primates.
Dr. C. Venkatraman, is a
Senior Scientist in Zoological Survey of India.
Currently he is In-Charge of Mammal & Osteology section and
Ecology and Conservation division. He is expertise on birds and mammals
and surveyed many areas in Western Ghats as well as Eastern Ghats.
Author contribution: MK conducted the laboratory examinations, designed the
study and prepared the manuscript. KC directed and encouraged the study and
provided the necessary facilities to accomplish the work. JKD and CV supervised
the study.
INTRODUCTION
Mammalian hair characters are one
of the important features that can be used to identify
the species when the external morphology is unable to help with
identification in case only of a small part of the skin of the mammal is
available (Teerink 1991; Chakraborty & De
2010). Tricho-taxonomy
(the study of hair) is relatively significant in the study of the food habit of
carnivores and is supportive of controlling the illegal trade of wildlife and
its derivatives (Chakraborty & De 2010; Sahajibal
et al. 2010). There are many
researchers, viz., Mayer (1952), Stains (1958), Brunner & Comman (1974), Moore et al. (1974), Koppiker & Sabins (1976), Teerink (1991), Wallis (1993), Chakraborty & De
(2010), and Dharaiya & Soni
(2012), who have documented the different hair characters of mammals well. Least importance has been given to the
species belonging to the order Lagomorpha, except for
a few studies by Moore et al. (1974) and Teerink
(1991).
The order Lagomorpha
comprises of two living families: Ochotonidae and
Leporidae. The family Ochotonidae comprises the pikas,
under the single genus Ochotona; out of a total of 30 species
worldwide, India has seven species. The
family Leporidae includes hares and rabbits consisting of 61 species under 11
genera, of which India has four species under two genera (Wilson & Reeder
2005).
Ochotonids are distinguished by a
small-sized body (head-body length: average 15cm) and weighing 70–300 g, having
greyish-brown silky fur. Unlike leporids,
the pikas lack a visible tail and have short rounded
ears, short limbs, with the hind limbs being barely longer than the forelimbs
(Vaughn et al. 2000; Smith 2008; Sokolov et al.
2009).
The leporids are distinguished by
a medium-sized body (head and body length: 40–70 cm), long hindlimbs and feet,
a small visible tail, and relatively long ears (up to 20cm in
length). Most leporids are
counter-coloured, with dark-coloured dorsal pelage and light-coloured ventral
pelage. Pelage texture can be thick and
soft or coarse and woolly (e.g., Hispid Hare) and may become increasingly
sparse along the length of the ears.
Rabbits and hares have short bushy tales, which are sometimes
conspicuously marked, and the soles of their hind limbs are covered with hair
(Nowak 1999; Vaughn et al. 2000; MacDonald 2001; Sokolov et al. 2009).
The above-mentioned
morpho-taxonomic characters have differentiated the families Ochotonidae and Leporidae.
The present tricho-taxonomy study,
however, helps to differentiate the two families only with the help of hairs
when morpho-taxonomy is unable to offer the fruitful result (Teerink 1991; Chakraborty & De 2010).
METHODS
A bunch of dorsal guard hairs was
collected from five, dry, preserved skins of four pika
species, namely Ladakh Pika
Ochotona ladacensis (Günther, 1875),
Large-eared Pika Ochotona macrotis
(Günther, 1875), Royle’s Pika
Ochotona roylei (Ogilby,
1839), and Moupin’s Pika Ochotona
thibetana (Milne-Edwards, 1871) of the family Ochotonidae, and three species of hare, namely, Hispid Hare
Caprolagus hispidus (Pearson,
1839), Indian Hare Lepus nigricollis F. Cuvier
(1823), and Woolly Hare Lepus oiostolus Hodgson
(1840) of the family Leporidae, housed at the National Zoological Collections
of Zoological Survey of India, Kolkata, India.
The morphological characters of
hairs (n=20) such as colour, number of bands and profile of hairs were
recorded, and the length and diameter of hairs were measured using a dial
calliper (Mitutoyo). To study the
cuticular characters, the acetone washed hair samples were placed over the
varnish coated-microscopic glass slide and the dried hairs were dragged gently
over it to leave the imprint of scales over the microscopic glass slide. To study the medulla characters, the hair
samples were mounted over the microscopic glass slide using D.P.X. To study the shape of the cross section, the
hair samples were hand sliced and mounted over the microscopic glass slide
using D.P.X. The cuticular characters of
hair such as scale position, scale patterns, structure of scale margins and
distance between scale margins, the medullary characters such as width
composition, the structure and form of margins of the medulla and the shape of
cross-section of hairs were examined and photographed (400x magnifications)
using a digital camera set onto an optical microscope (Olympus BX41).
To obtain the three-dimensional structure and a
more detailed examination of cuticular scales of the hair, the scanning
electron microscope (ZEISS Evo18 - special edition) was used. The cuticular structures of hairs were
observed under the high magnifications 1630x and 2600x, and the observed
cuticular structures of hairs were photographed.
The measurement data such as the
maximum, minimum, mean and standard deviation of cuticular scales and medulla
were obtained through the digital scale fitted on an optical microscope. The
methodology was followed according to the descriptions provided by Brunner
& Comman (1974) and Teerink
(1991). The description of different
terms of patterns used in the results and discussion that have been given
herewith were followed from Teerink (1991) and the
nomenclature of colour was followed as per Ridgway
(1886).
RESULTS
Family Ochotonidae
The pelage colour of four species
of the family Ochotonidae show different shades of
brownish-grey; however, the colour of single guard hairs that was observed was
grey-buff. The hair of all four
species were observed as bicoloured with two bands. The profile of the hair of all species had
shown no variations and was observed as a wavy form (Table 1).
The mean length of hair
significantly varied among the four species (range: 8.5–22.6 mm): the maximum
length was recorded in Ochotona roylei (16.6±3.4
mm) and the minimum in O. ladacensis (11.7±1
mm), the mean length of hair of O. macrotis and O. thibetana were recorded as 15.6±4.7 and
16.3±3.1 mm, respectively (Table 1). The
mean diameter of hair also significantly varied among the four species (range:
11.4–56.3 µm): The maximum diameter was recorded in O. macrotis (44.7±14.4 µm) and the minimum
in O. thibetana (32.2±10
µm), the mean diameter of hair of O. ladacensis and O. roylei was recorded as 38.6±11.4 and 33.4±8.2
µm, respectively (Table 1).
The hair of four
species had shown almost similar cuticular characters (Images 1 &
7) between the species: the scale position, scale patterns, the structure
of scale margins and distance between scale margins were observed in all
the four species as ‘transversal’, ‘streaked’ (‘regular wave’
in O. thibetana), ‘smooth’
and ‘near’, respectively (Table 2).
The measurement values had shown
significant variations among the four species, the mean scale count
per millimetre length of hair (range: 69–201 µm) was
highest in O. ladacensis (158±34.8
µm) and lowest in O. roylei (82.8±11.7
µm). The mean length of cuticular scales
(range: 20–37.9 µm) was observed; as a maximum (35.9±1.2 µm) in O. thibetana and as a minimum (21.8±1.7 µm)
in O. ladacensis. The
mean width of cuticular scales (range: 4.3–13.6 µm) was highest in O. ladacensis (10.3±2.1 µm) and lowest in O. thibetana (6.3±1.7 µm) (Table 1).
The medullary characteristics of
hair (Image 2) showed no variations between four species: the
composition of medulla, the structure of medulla and medulla margins were
observed as ‘multicellular’, ‘isolated’ and ‘scalloped’, respectively (Table
3).
The mean width of medulla
(range: 27.1–47.8 µm) showed slight variations among the species. Ochotona ladacensis had the highest (45.1±1.1 µm) mean
medullary width while the lowest (34.3±2.8 µm) was in O. thibetana.
The mean medullary width of O. macrotis and O. roylei were recorded as 39.3±3 and 34.6±1.1 µm,
respectively (Table 3).
The cross-section of hair (Image
3) of the species showed similar shapes in the family Ochotonidae
and was observed as an oval shape in all the four ochotonid species
(Table 3).
Family Leporidae
The pelage colour
of the three species of the family Leporidae had shown different shades of
blackish-grey and the colour of a single guard hair
had also shown various shades of black yellow.
The hair of all three species were observed as bicoloured
with 3–4 bands. The profile of the hair
had shown slight variations and was observed as slightly wavy in C. hispidus, and wavy in both L. nigricollis and L. oiostolus (Table 1).
The mean length of hair
significantly varied among the three species (range: 10.3–34 mm): the maximum
length was observed in C. hispidus (27.5±6.6
mm) and minimum in L. nigricollis (18.5±3.4
mm), whereas the mean length of hair of L. oiostolus was
recorded as 21.8±7.5 mm (Table 1). The
mean diameter of hair also significantly varied among the three species (range:
36.1–166.5 µm): the maximum diameter was observed in C. hispidus (113.2±39.6 µm) and minimum in L. oiostolus (65.8±14.8 µm), whereas the mean
diameter of hair of L. nigricollis was
recorded as 78.6±13.4 µm (Table 1).
The cuticular characteristics of
hairs of all the three leporid species (Images 4 & 8) had
shown no variations between the species and were observed with scale position-
‘transversal’, scale patterns- ‘regular wave’, the structure of scale margins-
‘smooth’ and distance between scale margins- ‘near’. The measurement values had shown slight
variations among the species, the mean scale count per millimetre
length of hairs (range: 118-226 µm) were observed as maximum in C. hispidus (200.6±15.7 µm) and minimum in L. nigricollis (137.9±14.2 µm), whereas L. oiostolus was 148.6±8.5 µm. The mean length of scale (range: 34.6–116.2
µm) was observed to be the highest in C. hispidus (99.9±7.8
µm) and the lowest in L. oiostolus
(37.1±2.1 µm), whereas L. nigricollis was
49.3±1.3 µm. The maximum and minimum of
mean scale width of hair (range: 7.4–15.1 µm) was recorded in L. oiostolus (14.3±0.8 µm) and C. hispidus (9.3±2.2 µm), respectively, where L. nigricollis was 12.2±1.3 µm (Table 2).
The medullary characteristics of
the hair of three species (Image 5) had shown similar characters
between the species and were observed as the composition of medulla-
‘multicellular in rows’, the structure of medulla- ‘multiserial
ladder’ and ‘medulla margins- scalloped’. The mean width of medulla was
observed to be the highest as 77.1±1.6 µm in C. hispidus and lowest as 65.9±1.2 µm in L. nigricollis, whereas L. oiostolus was 65.9±1.2, µm (Table 3).
The cross-section of hair of the
species (Image 6) showed similar shapes in the family Leporidae and was
observed as a dumb-bell shape in all the three leporid species (Table
3).
DISCUSSION
Family Ochotonidae
The pikas
can be distinguished as the family of the order Lagomorpha
by their specific cuticular scale pattern and unique medullary structure such
as the different cuticular patterns. The
multicellular composition of medulla and isolated structure of medulla of hair
differentiates it from the other groups which is confirmed by comparing the
previous study of Koppiker & Sabins
(1976), Teerink (1991), Chakraborty & De
(2010), Dharaiya & Soni
(2012), Kamalakannan (2018, 2019). The hair characters, however, are similar
between the four species studied. The hair characteristics of pikas of Wyoming, United States by Moore et
al. (1974) reviewed that the identification hairs of pika up to the species level is difficult, as the
microscopic characters of hairs are similar and the present study also supports
the same.
Family Leporidae
The hare of the family Leporidae
is one of the easiest to distinguish because of its specific cuticular scale
position and pattern, and unique medulla structure and the dumb-bell shape of
the cross-section. The transverse cuticular
and multiserial ladder medulla patterns of hair
differentiates it from the other groups of mammals (Chakraborty & De 2010;
Sarkar 2011; Kamalakannan 2018, 2019). The above-mentioned characters are similar in
all the three species. The present study shows that the result is
consistent with the findings of hares that occur in Wyoming, Unites States by
Moore et al. (1974) and western Europe by Teerink
(1991).
According to Hoffmann & Smith
(2005), the difference between the order Lagomorpha
and Rodentia had been discussed first by Simpson (1945). Later, many morphological and molecular
phylogeny studies supported the differences between the order Lagomorpha and Rodentia (Huchton
et al. 1999). As mentioned earlier, the
hares are often differentiated by external morphology from the pikas by the medium-sized body, and length of their
tails and ears. The hares have a highly
arched skull, pikas have a less arched skull; the
hares have an upright posture of the head, strong hindlimbs and pelvic girdle,
which the pikas lack (Vaughn et al. 2000;
Sokolov et al. 2009). The dental formula (incisors, canines,
premolars and molars of the upper and lower jaw) also varies between these two
groups as 2.0.3.3/1.0.2.3x2 = 28 and 2.0.3.2/1.0.2.3x2 = 26 in the hares
and pikas, respectively (Sokolov
et al. 2009). The present tricho-taxonomic
study also shows the difference between the families Ochotonidae
(pikas) and Leporidae (hares) under the order Lagomorpha by highlighting the unique characters of
cuticula, medulla and cross-section.
Identification up
to species level of the order Lagomorpha was
difficult through tricho-taxonomic study, as all
the four ochotonid species and three leporid species have similar microscopic
characters between the species (Moore et al. 1974; Teerink
1991). The macroscopic characters of
hair of mammals may also differ due to age, sex, season, climate, geographical
variations, etc., especially since the pikas change
pelage colour seasonally (Grange 1932; Nowak 1999;
Vaughn et al. 2000; Grzimek 2003; Smith 2008). The macroscopic and microscopic characters
(Table 1–3) and the microscopic photographs (Images 1–8) of dorsal guard hairs
of lagomorphs would be helpful in the identification of species under the
families Ochotonidae and Leporidae of the order Lagomorpha by
considering the combination of all the characters of hairs.
CONCLUSION
It should be noted that very
meagre information is available in the literature on tricho-taxonomic
studies of species under the order Lagomorpha particularly
as there is no tricho-taxonomic study in
India. Thus, this study may be regarded
as the first attempt from India.
Hare species are highly
trafficked due to the local bush-meat consumption (Menon & Kumar
1999). They are the chief prey of small
and large carnivores, similarly, pikas are also
chief prey of small carnivores. Hence, the identification keys (provided
here) would be useful in animal forensic science as well as in food habit
analysis of carnivores.
Table 1. Macroscopic characteristics of dorsal guard
hairs of the species of the order Lagomorpha.
Species |
Coat
colour |
Colour
of hair |
Base |
Tip |
No.
of Bands |
Profile |
Length
(mm) |
Width
(µm) |
Family
Ochotonidae |
||||||||
O. ladacensis |
Orangeish,
sandy brown or grey |
Bicoloured |
Slate gray |
Buff |
2 |
Wavy |
10.3–13.5
(11.7±1) |
17.4–49.1
(38.6±11.4) |
O. macrotis |
Pale
brownish-grey with an ochre tinge |
Bicoloured |
Gray |
Buff |
2 |
Wavy |
8.5–21.6
(15.6±4.7) |
18.1–56.3
(44.7±14.4) |
O. roylei |
Rufous grey |
Bicoloured |
Gray |
Earth
yellow |
2 |
Wavy |
11.6–22.6
(16.6±3.4) |
18.1–41.2
(33.4±8.2) |
O. thibetana |
Rich russet
brown |
Bicoloured |
Slate gray |
Earth
yellow |
2 |
Wavy |
13.1–22.6
(16.3±3.1) |
11.4–40.1
(32.2±10) |
Family
Leporidae |
||||||||
C. hispidus |
Brown with
black grizzled hair |
Bicoloured |
Black |
Yellow |
4 |
Slightly
wavy |
14.9–34
(27.5±6.6) |
71.5–166.5
(113.2±39.6) |
L. nigricollis |
Reddish-brown
with black hair |
Bicoloured |
Cream |
Black |
3 |
Wavy |
12–23.2
(18.5±3.4) |
64.1–109.2
(78.6±13.4) |
L. oiostolus |
Black
grizzled with brownish-grey |
Bicoloured |
Pale yellow |
Black |
4 |
Wavy |
10.3–33.2
(21.8±7.5) |
36.1–76.1
(65.8±14.8) |
Table 2. Cuticular characteristics of dorsal guard
hairs of the species of the order Lagomorpha.
Species |
Scale
position |
Scale
patterns |
Structure
of scale margins |
Distance
between scale margins |
Scale
count/mm length of hair |
Length
of scale (µm) |
Width
of scale (µm) |
Family
Ochotonidae |
|||||||
O. ladacensis |
Transversal |
Streaked |
Smooth |
Near |
104–201
(158±34.8) |
20–26.3
(21.8±1.7) |
6.7–13.6
(10.3±2.1) |
O. macrotis |
Transversal |
Streaked |
Smooth |
Near |
104–160
(139.6±18.5) |
23.8–29.6
(27.4±1.6) |
6.7–13.6
(9.4±2) |
O. roylei |
Transversal |
Streaked |
Smooth |
Near |
69–102
(82.8±11.7) |
28.1–32.1
(30.6±1.4) |
6.9–10.2
(8.1±1.4) |
O. thibetana |
Transversal |
Regular
wave |
Smooth |
Near |
103–163
(125.8±18.3) |
34.1–37.9
(35.9±1.2) |
4.3–9.2
(6.3±1.7) |
Family
Leporidae |
|||||||
C. hispidus |
Transversal |
Regular
wave |
Smooth |
Near |
176–226
(200.6±15.7) |
88.7–116.2
(99.9±7.8) |
7.4–11.4
(9.3±2.2) |
L. nigricollis |
Transversal |
Regular
wave |
Smooth |
Near |
118–168
(137.9±14.2) |
47.1–51.3
(49.3±1.3) |
9.6–13.2
(12.2±1.3) |
L. oiostolus |
Transversal |
Regular
wave |
Smooth |
Near |
135–160
(148.6±8.5) |
34.6–40.8
(37.1±2.1) |
14.2–15.1
(14.3±0.8) |
Table 3. Medullary characteristics and shape of
cross-section of dorsal guard hairs of the species of the order Lagomorpha.
Species |
Composition
of medulla |
Structure
of medulla |
Margins
of medulla |
Width
of medulla (µm) |
Shape
of cross-section |
Family
Ochotonidae |
|||||
O. ladacensis |
Multicellular |
Isolated |
Scalloped |
44.1–47.8
(45.1±1.1) |
Oval |
O. macrotis |
Multicellular |
Isolated |
Scalloped |
34.6–45.6
(39.3±3) |
Oval |
O. roylei |
Multicellular |
Isolated |
Scalloped |
33.1–36.1
(34.6±1.1) |
Oval |
O. thibetana |
Multicellular |
Isolated |
Scalloped |
27.1–38.1
(34.3±2.8) |
Oval |
Family
Leporidae |
|||||
C. hispidus |
Multicellular in rows |
Multiserial
ladder |
Scalloped |
7.4–11.4
(9.3±2.2) |
Dumb-bell |
L. nigricollis |
Multicellular in rows |
Multiserial
ladder |
Scalloped |
64.1–68.1
(65.9±1.2) |
Dumb-bell |
L. oiostolus |
Multicellular in rows |
Multiserial
ladder |
Scalloped |
64.1–69.8
(66.9±2) |
Dumb-bell |
REFERENCES
Brunner, H.
& B. Coman (1974). The identification of
mammalian hair. Inkata Press, Melbourne,
Australia, 176pp.
Chakraborty,
R. & J.K. De (2010). Atlas on hairs Indian mammals. Part- I: Carnivora.
Zoological Survey of India, Kolkata, 141pp.
Dharaiya, N. & V.C. Soni (2012). Identification of hairs of some
mammalian prey of large cats in Gir protected area,
India. Journal of Threatened Taxa 4(9): 2928–2932. https://doi.org/10.11609/JoTT.o3032.2928-32
Grange, W.B.
(1932). The pelages
and color changes of the snowshoe hare, Lepus americanus
phaeotus, Allen. Journal of Mammalogy
13: 99–116.
Grzimek, B.
(2003). Artiodactyla (Even-toed ungulates). pp. 263-417. In:
Hutchins, M., D. Kleiman, V. Geist, M. McDade (eds.) Grzimek’s Animal
Life Encyclopaedia, Vol. 15, Mammals IV, 2nd
Edition. Farmington Hills, Michigan, USA: Gale Group, 480pp.
Kamalakannan, M. (2018). The identification of Takin Budorcas
taxicolor (Mammalia: Bovidae)
through dorsal guard hair. Journal of Threatened Taxa 10(15):
13014–13016. https://doi.org/10.11609/jott.3357.10.15.13014-13016
Kamalakannan, M. (2019). Characterization of dorsal guard hair of the wild goats and sheep (Bovidae: Caprinae) occurring in
the Himalaya and Western Ghats of India. Journal of Threatened Taxa
11(3): 13304–13309. https://doi.org/10.11609/jott.3344.11.3.13304-13309
Koppiker, B.R. & J.H. Sabins (1976). Identification of hairs of some
Indian mammals. Journal of the Bombay Natural History Society 73: 5–20.
Hoffmann,
R.S. & A.T. Smith (2005). Lagomorpha, pp. 185–211. In: Wilson,
D.E. & D.M. Reeder, D. M. (eds.). Mammal Species of the World: A
Taxonomic and Geographic Reference- 3rd Edition. Johns Hopkins
University Press, 2142pp.
Huchon, D., F.M. Catzeflis & E.J.P. Douzery (1999). Molecular evolution of the
nuclear Willebrand factor gene in mammals and the phylogeny of rodents. Molecular
Biology and Evolution 16: 577–589.
MacDonald, D.
(2001). The
Encyclopaedia of Mammals. Andromeda Oxford Limited, Oxford, 944pp.
Mayer, W.V.
(1952). The hair of
California mammals with keys to the dorsal guard hairs of California mammals. American
Midland Naturalist 38: 480–512.
Menon, V.
& A. Kumar (1999). Wildlife Crime: An Enforcement Guide. Wildlife Protection Society of
India, New Delhi, 111pp.
Moore, T.D.,
L.E. Spence & C.E. Dugnolle (1974). Identification of the dorsal
guard hairs of some mammals of Wyoming. Game and Fish Department, Wyoming,
177pp.
Nowak, R.
(1999). Order Lagomorpha, pp. 1715–1738. In: Nowak, R. (ed.) Walker’s
Mammals of the World, Vol. 2, 6th Edition. Johns Hopkins
University Press, Baltimore and London, 2015pp.
Ridgway, R.
(1886). Nomenclature
of colours. University Press, John Wilson and Son, Cambridge, 129pp.
Sahajibal, V., S.P. Goyal, K. Singh & V. Tahkur
(2010). Dealing
wildlife offences in India: Role of the hair as physical evidence. International
Journal of Trichology 1: 18–26.
Sarkar, P.S.,
J.K. De & C.K. Manna (2011). Identification of dorsal guard hair of five species
of the family Cercopithecidae (Primates: Mammalia). Current
Science 100: 1725–1728.
Simpson, G.G.
(1945). The
principles of classification and a classification of mammals. Bulletin
of the American Museum of Natural History 85: 1–350.
Smith, A.
(2008). The world of
pikas, pp. 89–102. In: Alves, P., N. Ferrand, K. Hackland (eds.) Lagomorph Biology: Evolution,
Ecology, and Conservation. Springer-Verlag, Berlin, XVIII+414pp.
Stains, H.J.
(1958). Field key to
guard hair of middle western furbearers. Journal of Wildlife Management 22:
95–97.
Sokolov, V.E., E. Yu. Ivanitskaya, V.V. Gruzdev & V.G. Heptner
(2009). Lagomorphs-
Mammals of Russia and Adjacent Regions. Smithsonian Institution Libraries,
Amerind Publishing Co. Pvt. Ltd, New Delhi, 400pp.
Teerink, B.J. (1991). Hair of West-European Mammals Atlas and Identification Key.
Cambridge University Press, Cambridge, 223pp.
Vaughn, T.,
J. Ryan. & N. Czaplewski (2000). Mammalogy, 4th
Edition. Brooks-Cole, Fort Worth, 672pp.
Wallis, R.L.
(1993). A key for
the identification of guard hairs of some Ontario mammals. Canadian Journal
of Zoology 71: 587–591.
Wilson, D.E. & D-A.M. Reeder
(Eds.) (2005). Mammal
Species of the World: A Taxonomic and Geographic Reference (3rd
Edition). Johns Hopkins University Press, Baltimore, 1 & 2: 2141pp.