size of the brown hare (lepus europaeus pallas, 1778) living in

size of the brown hare (lepus europaeus pallas, 1778) living in

2Zoologica
37
Z E - O F -49/1-4:
T H E - H A237-244
RE -LIVING-IN-POMERANIA
PoloniaeS I(2004)
237
SIZE OF THE BROWN HARE (LEPUS EUROPAEUS
PALLAS, 1778) LIVING IN CENTRAL POMERANIA
IN POLAND
P IOTR M YS£EK 1, E L¯BIETA K ALISIÑSKA 1
and B ART£OMIEJ B ARTYZEL 2
Department of Zoology, University of Agriculture, 20 Doktora Judyma Street,
71-466 Szczecin, Poland
2
Department of Morphological Sciences, Warsaw Agricultural University, 159
Nowoursynowska Street, 02-776 Warszawa, Poland. [email protected]
1
Abstract. Sixty-four brown hares were examined, including 20 males (7 young
and 13 adult ones) and 44 females (18 young and 26 adult ones). The body weight
(BW), body length (BL), and sternum length (SL) were established. The relation between the strongest correlated parameters - body weight (BW) and body length (BL)
was described with the following allometric equation logBL = 0.326logBW + 0.615.
Moreover, two indicators characterising the relative body length were calculated: BL/
BW and SL/BW both for selected age and sex groups as well as for all examined
individuals. Comparisons of appropriate average values of absolute and relative parameters with dimorphic and ontogenetic character were also made.
INTRODUCTION
Mammals' body size is most frequently described by means of body weight
and certain linear measurements - usually the body length; other measurements,
like sternum length or chest circumference, are less often used (SZUBA et al.,
1988; SCHMIDT -N IELSEN , 1994; M ELOSIK, 1997). In small mammals, apart from body
weight and body length, ear height and hind foot length measurements are also
used (P UCEK , 1984). The mentioned parameters are used in systematic, morphological, ontogenetic, and ecological studies; sometimes also in establishing
appropriate relations of allometric character (G OULD , 1966; S ZUBA et al., 1988;
R EISS , 1991). Not many such studies were published as regards the brown hare,
X V I I I C o n g r e s s o f P o l i s h Z o o l o g i c a l S o c i e t y, 1 5 - 1 8 S e p t e m b e r 2 0 0 3 , To r u ñ , P o l a n d
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238
and the most important studies discussing the body weight or length of this
species include works by C ABOÑ -R ACZYÑSKA (1964), P IELOWSKI (1969); M ACE et
al. (1981), B OMBIK (1997). This study is devoted to the body size of the brown
hare from Central Pomerania and the following absolute parameters were included in it: body weight, body and sternum length, and certain relations among
them that were expressed by means of appropriate indicators and an allometric
equation.
MATERIAL AND METHODS
Material comprised 64 individuals of brown hare (Lepus europaeus P ALLAS ,
1778): 20 males (7 young and 13 adult ones) and 44 females (18 young and 26
adult ones). They came from the area of 4 municipalities: Cz³uchów, Debrzno,
Przechlewo, and Rzeczenica in the County of Cz³uchów. The described area is
located in the southern part of Central Pomerania. The hares for the studies
were delivered by hunters. They were achieved in the hunting season, i.e.
between 15th October and 15th January, in the years 1998-2001. For the needs
of this study the brown hares were divided into two age groups: young animals
(up to one year old, hunted during the first winter in their lives) and adult
animals (hunted at least in the second year of their lives). The qualification of
the individuals to one of the categories was based on the size of external sex
organs and the presence or lack of Stroh's mark, or a cartilaginous swelling on
a forearm (S EMIZOROWA , 1987; P IELOWSKI , 1979). The sex of the hunted animals
was established on the basis of the look of external reproductive organs and the
identification of gonads during post-mortems.
The hunted brown hares were weighed with a Pesola spring balance exact
to 50g and were linearly measured. The body length was measured at the side
of the back from apex nasi to epiphysis cauda (with a measuring tape exact to
5mm) and sternum length was measured with a vernier calliper gauge (exact to
1mm).
Apart from absolute parameters, several indicators characterising relative
body sizes of brown hares and an appropriate allometric equation (G OULD 1966)
describing the relation between body weight (BW) and body length (BL) were
established. General formula of the linear allometric equation is as follows:
Log Y = b log X + A
where X is an independent variable, Y - dependent variable, "b" and "A"
are constants of the equation.
The relative indicators and the mentioned equation were calculated only
in case of noticing (for n=64) relevant linear correlation between the examined
parameters. For the average absolute values and relative parameters, that were
also established for selected sex and age groups, dimorphic and ontogenetic
comparisons were made (using t-Student test). Moreover, an attempt was made
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239
to establish significant relations between body size and age and sex of the
examined animals. All statistical calculations were made using Statistica 5.5 a
computer software (StatSoft, Inc. 2000).
RESULTS
Brown hares from the Cz³uchów area on average weighed 4130 g. Their
body length was 62 cm, and sternum length was 12.4 cm. The linear correlation
for all individuals in the aggregate (n = 64) turned out to be significant for
relations between: 1/ body weight and body length (r = 0.755; p < 0.0001), 2/
body weight and sternum length (r = 0.4; p < 0.001), 3/ body weight and age
(r = 0.366; p < 0.01), 4/ body length and age (r = 0.475; p < 0.0001), 5/ body
weight and sex (r = 0.246; p < 0.05).
Table 1
Absolute
size
of
body
of
brown
hare
and differences between males and females
_
(x - arythmetic mean; SD - standard deviation; V - coefficient of variation; t - t-Student
test; p - significance level; NS - difference non-significant; ranges given in parantheses)
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P.-MYS£EK-et-al.
240
A strong correlation between body weight (BW) and its length (BL) implied the establishment of an appropriate allometric equation, which was as
follows:
log BL = 0.326 log BW + 0.615
Absolute parameters
Dimorphic comparisons were made in order to search differences between
males and females in groups of young and adult brown hares (Table 1). No
statistically significant differences in the size of the examined parameters were
recorded in any of the age groups. In further considerations of ontogenetic
character all young individuals (n = 25) were compared to adult individuals (n
= 39) without differentiating them in respect to sex. Adult brown hares were
clearly heavier (t=3.096; p<0.01) and longer (t = 4.25; p < 0.0001) than young
ones, but the lengths of their sternums were similar.
Relative indicators
Among parameters that were significantly correlated, two relative indicators were established: BL/BW and SL/BW (using multiplier 100), or the relation
of body length (BL) to body weight (BW) and sternum length (SL) to body
Table 2
Relative size of body of brown hare and some differences between males and
females. For explanation of symbols see Tab.1.
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SIZE-OF-THE-HARE -LIVING-IN-POMERANIA
241
weight (BW). The obtained results and dimorphic comparisons were presented
in Table 2. Among young brown hares significant differences between males
and females were recorded only in the value of SL/BW indicator (t = 2.24, p <
0.05). This indicator was by 11.8% bigger in males than in females.
The adult individuals were compared to young ones within sex groups. It
was noticed that SL/BW indicator was bigger (by 8.8%) in young males in
comparison to adult ones (t = -2.26; p < 0.05). In the group of females no
significant differences in the values of the examined indicators were observed.
Ontogenetic comparisons between all young (n = 25) and adult (n = 39)
brown hares did not show any differences in the value of BL/BW indicator, but
SL/BW indicator turned out to be bigger by 3.33% in young individuals in
comparison to adult ones (t = -2.08; p < 0.05).
DISCUSSION
The average weight established for all examined brown hares from the
Cz³uchów area (4130 g) is very similar to the average weight of hares from
Wielkopolska (Great Poland Region) established by C ABOÑ -R ACZYÑSKA (1964) namely 4120g. This author (C ABOÑ -R ACZYÑSKA , 1964) also gave body weights of
hares included by her in one of four age groups. Body weight analysis taking
into consideration age revealed that brown hares from the Cz³uchów area were
heavier than those from Wielkopolska (young ones by 300 g and adults by 140 g).
Larger range of brown hares' body weight variability was recorded in former
Poznañ Province (1000-5250 g), which was probably the result of examining more
animals (432 individuals), among which there were 30 individuals of less than
2 kg in weight (C ABOÑ -R ACZYÑSKA , 1964). Also B OMBIK (1997) studied the size of
brown hares in Poland and she stated that individuals from the G³ogów area on
average weighed 3934 g, the ones hunted near Czempiñ in former Poznañ Province - 4248 g, and from Siedlce region - 4048 g. The mentioned data show that
brown hares in various parts of Poland may have differing average body weight,
which may be the result of a certain population variability or/and examining a
group of individuals not even in respect of age. Comparing body weights of
brown hares living in Poland to representatives of this species from Western
Europe one may say that fully grown up individuals from our country are about
twice as heavy, since those from Western Europe on average weigh only 1954 g
(M ACE et al., 1981). Such a big difference in body weights of brown hares from
various parts of Europe is connected with so-called Bergmann's Rule, according
to which hares, and other mammals, are considerably smaller in warmer Western
and Southern Europe, and their size increases towards the north-west, thus
aiming in the cold climate at decreasing relation of body area to its volume,
which is a derivative of weight (SCHMIDT -N IELSEN , 1994). It seems that even in
Poland the trend is noticeable, since the weight of brown hares increases in our
country according to this rule from about 3500g in individuals living in Lower
Silesia to about 4500 g living in Suwa³ki Region, where individual specimens
reaching 6500 g were recorded (P IELOWSKI , 1979; P UCEK , 1984).
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242
The average body length of the brown hare measured at the side of the
back was 62.1 cm (55-68 cm). C ABOÑ -R ACZYÑSKA (1964) recorded lower value for
individuals from Wielkopolska - only 54.5 cm (50-53 cm), but she did the body
measurement at the stomach side and she admits that her results in this respect
are a little lowered in comparison to results of other authors due to differently
measured body length. Basing on the allometric equation established in this
study for the relation body weight- body length, an expected body length was
calculated for the average weight of the brown hare given by CABOÑ -R ACZYÑSKA
(1964): 4120 g. Such "an average brown hare" from Wielkopolska should be 62 cm
long (from the nose to epiphysis cauda). So, it can be assumed that body
measurement at the stomach side is lower in comparison to an analogous measurement made at the side of the back by about 7 cm.
It seems that the relation between body weight and body length of the
brown hare, a not very large mammal, is the same as in other small mammals,
since an analogous equation established for a multispecific group of rodents by
TOWE and MANN (1992) has very similar constants: log BL = 0.322 log BW + 0.547.
The value of BL/BW indicator for other hare species (adult individuals)
was calculated on the basis of the data on body weight and body length taken
from the study by MACE et al. (1981): the black-tailed jack rabbit Lepus californicus
and the Arctic hare Lepus arcticus. This indicator was 2.30 and 1.61 respectively. In the adult brown hare from the Cz³uchów area this indicator is considerably lower (1.49).
According to S TRAWIÑSKI (1976) the sternum length measurement was proposed in 1931 but it was not very often used in anatomical analyses, although
it seems a very good indicator of body size, especially in birds and small
mammals. Its advantage is the reduction of a specimen size and uniformity of
a measured element, which is a bone in this case (S TRAWIÑSKI , 1976). The average
sternum length of the brown hare from the Cz³uchów area was 12.4 cm and no
ontogenetic or dimorphic differences were recorded. Comparisons of the indicators describing the relative sternum length (SL/BW.•.100) gave interesting results. This indicator turned out to be larger in young males than in females.
That was probably the result of overlapping statistically insignificant differences in body weight (it was a little bigger in females) and in sternum length
(SL), which was longer in males (Table 1).
STRESZCZENIE
WIELKOŒÆ ZAJ¥CA SZARAKA (LEPUS EUROPAEUS PALLAS, 1778)
BYTUJ¥CEGO NA POMORZU ŒRODKOWYM W POLSCE
W niniejszej pracy opisano wielkoœæ cia³a zaj¹ca szaraka bytuj¹cego na
Pomorzu Œrodkowym. Przebadano 64 zwierzêta upolowane w obwodach ³owieckich
w powiecie Cz³uchów. Oznaczono p³eæ zwierz¹t i podzielono je na dwie grupy
wiekowe (m³ode - w pierwszym roku ¿ycia oraz doros³e - starsze ni¿ jednoroczne).
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243
Pomiary obejmowa³y masê cia³a (BW), d³ugoœæ cia³a (BL) oraz d³ugoœæ mostka
(SL). Pomiêdzy parametrami, które by³y ze sob¹ istotnie skorelowane ustalono
dwa wskaŸniki wzglêdne: BL/BW i SL/BW. Dokonano tak¿e porównañ odpowiednich
œrednich wartoœci parametrów bezwzglêdnych i wzglêdnych o charakterze
dymorficznym oraz ontogenetycznym. Korelacje liniowe dla wszystkich osobników
³¹cznie (n = 64) okaza³y siê istotne statystycznie dla zale¿noœci pomiêdzy:
1/ mas¹ cia³a a d³ugoœci¹ cia³a, 2/ mas¹ cia³a a d³ugoœci¹ mostka, 3/ mas¹ cia³a
a wiekiem, 4/ d³ugoœci¹ cia³a a wiekiem, 5/ mas¹ cia³a a p³ci¹. Zale¿noœæ miêdzy
najsilniej skorelowanymi ze sob¹ parametrami: mas¹ cia³a i jego d³ugoœci¹ zosta³a
opisana równaniem allometrycznym: log BL = 0,326 log BW + 0,615 (r = 0,755).
Œrednia masa cia³a zaj¹ca szaraka z okolic Cz³uchowa wynosi³a 4130 g,
d³ugoœæ cia³a 62 cm, a d³ugoœæ mostka 12,4 cm. Doros³e zaj¹ce szaraki by³y
wyraŸnie ciê¿sze i d³u¿sze od m³odych, ale d³ugoœæ ich mostków by³a podobna.
Ró¿nic w wielkoœci wymienionych parametrów pomiêdzy samcami a samicami nie
stwierdzono.
WskaŸnik SL/BW by³ o 11,8 % wiêkszy u m³odych samców ni¿ u samic.
M³ode samce mia³y o 8,8 % wiêksz¹ wartoœæ tego wskaŸnika ni¿ samce doros³e.
Porównania o charakterze ontogenetycznym pomiêdzy wszystkimi m³odymi (n = 25)
i doros³ymi (n = 39) osobnikami nie wykaza³y ró¿nic w wielkoœci wskaŸnika
BL/BW, lecz wskaŸnik SL/BW okaza³ siê o 3,33% wiêkszy u m³odych osobnikó
w w porównaniu z doros³ymi (ró¿nica statystycznie istotna).
REFERENCES
B OMBIK , E.J., 1997: Sk³ad mineralny tkanek zaj¹ca szaraka (Lepus europaeus P ALL .)
jako wskaŸnika zasobnoœci œrodowiska przyrodniczego. Praca doktorska,
WSR-P Siedlce.
C ABOÑ -R ACZYÑSKA , K., 1964: Studies on the European hare. II. Variations in the weight
and dimensions of the body and the weight of certain internal organs. Acta
theriol., 16: 233-248.
G OULD, S.J., 1966: Allometry and size in ontogeny and phylogeny. Biol. Rev., 41: 587-640.
M ACE , G.M., H ARVEY , P.H., C LUTTON -B ROCK , T.H., 1981: Brain size and ecology in small
mammals. J. Zool., Lond., 193: 333-354.
M ELOSIK , M., 1997: Studium morfometryczne wzrostu byd³a domowego Bos promigenius
f. taurus w okresie p³odowym. Rozprawa nr 177, AR Szczecin.
P IELOWSKI, Z., 1969: Sex ratio and weight of hares in Poland. Acta theriol., 14: 119-131.
P IELOWSKI , Z., 1979: Zaj¹c. PWRiL, Warszawa.
P UCEK , Z., 1984: Klucz do oznaczania ssaków Polski. PWN, Warszawa.
R EISS , M.J., 1991: The allometry of growth and reproduction. Cambridge University
Press.
S CHMIDT -N IELSEN , K., 1994: Dlaczego tak wa¿ne s¹ rozmiary zwierz¹t. Skalowanie.
PWN, Warszawa.
S EMIZOROWA , I., 1987: Zaj¹ce. W: L OCHMAN J. Okreœlanie wieku zwierzyny. PWRiL,
Warszawa: 152-165.
StatSoft, Inc., 2000: STATISTICA for Windows [Computer program manual]. Tulsa,
OK: StatSoft, Inc., 2300 East 14th Street, Tulsa.
244
P.-MYS£EK-et-al.
244
S TRAWIÑSKI , S., 1976: D³ugoœæ grzebienia mostka (Crista sterni) jako pomiar biometryczny
u ptaków. Acta Biol., 2: 23-29.
S ZUBA , Z., K ALISIÑSKA , E., B ABULA , Z., 1988: Grown of body weight and length of
bovine fetuses. Anat. Histol. Embryol. 17: 53-59.
T OWE , A.L., M ANN , M.D., 1992: Brain size body length relations among myomorph
rodents. Brain Behav. Evol., 39: 17-23.
Received 30.11.2003.