Hybridization Between Red and Sika Deer

zoo!. Anz., Jena 207 (1981) 5/6, S. 260-27.0

Hybridization Between Red and Sika Deer I. Craniological Analysis By LUDEK BARTOS, JAROMIR HyANEK and JIRI ZIROVNICKY Research Institute of Animal Production, Prague-Uhfineves (Czechoslovakia) With 5 Figures and 2 Tables

(Eingegangen am 13. November 1980)

Abstract During the investigation of the hybridization between red and sika deer in some areas of Czechoslovakia, several parallel methods were used. In the case of a skull examination it was: canonical variate analysis of craniological measurements; examimtion of the relation between the level of the aboral ends of the nasals and oral level of the orbits; recording the shape of the palatal bone; measurements of the external and internal angle of the mandibula. The exact "hybrid zone" within the graphical distribution of values of the first and second canonical variates was determined by means of confidence ellipses. The criterion, useful for distinquishing whether a skull comes from an "intermediate hybrid" or from a "pure" individual of either species (by means of one or more craniological dimension measurement) was mathematically derived. The relation between the level of the aboral ends of the nasals and oral level of the orbits as well as the shape of the palatal bone, as an expression of hybridization, is discussed. Individual interspecific hybrids were found in all the examined localities (West and Central Bohemia, Moravia). The results indicate that there might be a widespread interspecific hybridization within the examined areas.

Introduction Perhaps the first hybrids between red and sika deer were observed already in ninetep,n eightieth in England (WHITEHEAD 1964). This was probably connected with the first imports of sika deer to Europe. lVlany cases of this hybridization were described m the territory of Great Britain and Ireland at the break of the past and present century (DELAP 1968, HARRINGTON 1973, etc.). Other cases from different parts of Europe were described later (WETTSTEIN 1931, MOFFAT 1938, SARKISOV 1944, ANTONIUS 1951, FLEROV 1952, SALGANSKIY et al. 1963, ROCHOLL 1967, STEKLENEV 1969). These authors mostly describe the hybrids as a natural curiosity, apparently cause(~ by a break of the geogr8phical isolation of both initial species. Red deer (isubr3 deer, Cervus elaphus xantopygus) and sika deer (c. nippon) are in natural contact: on the Ussuri river in Northwestern China. Hybridization is a current occurenCe III this region. Hunters there have a special name for it: Chinda-guiza, and are fully aware that it is a hybrid. The first European explorers who saw the hybrid, described it even as a subspecies of sika deer. This was the case of MAAK and PRZEWALSKI (MIROLYUBOV 1949). This mistake was revealed very soon and all further authors who have written about these problems are at one (Y'ANKOVSIY, ABRAMOV, both quoted by MIROLYUBOV 1949, MIROLYUBOV 1949, FLEROV 1952, SOKOLOV 1959, GEPTNER et al. 1961, etc.). The reciprocal possibility was also

1. BARTOS et al.: Hybridization Between Red and Sika Deer. 1.

261

tested in the well known experiments conducted by Soviet breeders who wanted, in this way, to increase the size of antlers. These effort of breeders failed, but they describe a number of hybrids produced under controlled conditions, fully fertile in both sexes (MIROLYUBOV 1949, and others). Other such experiments have been recently performed in Ireland (HARRINGTON 1973, 1978 - personal communication). In Czechoslovakia as well as in other countries of Europe (BENNETSEN 1977) sika deer often escaped from game preserves to wilderness during the first half of the present century. This has naturally led to the infiltration of sika deer to living areas of red deer and the possibility of hybridization. This problem has been treated with the highest attention in England and Ireland, unfortunately quite recently (DELAP 1967, 1968; HARRINGTON 1973). LOWE and GARDINER (1975) using the results of craniological measurements by canonical variate analysis even concluded that in England the original red deer (c. elaphus scoticus) is lost as a species, due to hybridization with sika deer. The problem of the possibility of hybridization between red deer and sika deer attracted attention in Czechoslovakia only in 1976. At the international trophy show, organized within the "Z eme zivitelka" agricultural exhibition at Ceske Budejovice, the trophy comission excluded from evaluation one capital trophy of sika deer. This decision was based on suspicion that the trophy might come from a cross between sika and red deer. The investigation of the hybridization was performed by several parallell methods (BARTOS and ZIROVNICKY 1981, 1982) and was in part reported about in unpublished form already (BARTOS et al. 1978, 1979). This part of the study deals with the craniological data. Material and Techniques Measurements were made according to LOWE and GARDINER (1974). The data were processed by canonical variate analysis (BLACKITH and REYME,NT 1971, LOWE and GARDINER 1975). The confidence ellipse for sets of measurements (originally used for the first and second canonical variate determination) of both deer species were of the relation

(Xl ~Xlr + (X2~X2r

=

1

where xl = 1st canonical variate; Xl = arithmetical mean of 1st canonical variate; 01 = standard deviation of 1st canonical variate; x2 = 2nd canonical variate; x2 = arithmetical mean of 2nd canonical variate; 02 = standard deviation of 2nd canonical variate. The relation between the level of the aboral ends of the nasals and oral level of the orbits was examined (Fig. 1 A), because SOKOLOV (1959) stated that the aboral ends of sika deer nasal bones (in further text just "nasals") always meet or cross the oral level of the orbits, while in red deer the nasals are far from the level of the orbits. The shape of the palatal bone was recorded at the same time (Fig. 1 B, Fig. 3). Two angles - the "exterior" and "interior" were measured on the mandible (Fig. 1 C).

Results On the whole, 156 stag skulls and 37 hind skulls of both deer species were examined. They came from the breeders' shows in the region under study and from the owners of trophies in Bohemia and Moravia. The craniometric results of hinds are not included owing to the small number of animals examined. Two canonical variates (LOWE and GARDINER 1974, 1975) were used for graphical repre-

262

L. BARTOS et aL: Hybridization Between Red and Sika Deer. I.

Fig. 1. The traits studied on the skulls of red and sika deer. A) The level of nasals related to orbits

B) The palatal bone shape C) The "exterior" and "interior" angle measured on the mandible

sentation (Fig. 2). The variates are the same as those mentioned by LOWE and GARDINER (1974). Tab. 1 shows the vector elements for two canonical axes of the analysis illustrated in Fig. 2. In Fig. 2 the cluster of points closer to the abscissa represents the sika deer data, the cluster situated higher above the abscissa represents the data on red deer. The dubious trophy excluded from the international show in 1976 is marked by two circles. The confidence ellipse was calculated (P < 0.05) either for red deer data (the coordinate of the centre of the ellipse, the arithmetical mean of 1st canonical variate, are: - 90.009273; - 0.08811031; the axes of the ellipse are 7.7478; 0.811) or for sika deer data (the coordinates of the centre of the ellipse are: - 61.161295; - 0.8685621; the axes of the ellipse are 3.0516; 0.4097) (Fig. 2). The 1st canonical variate depleted 92.492.% of the whole

263

L. BARTOS et al.: Hybridization Between Red and Sika Deer. 1.

information. Hence the values of covariance between 1st canonical variate and each of 16 variables measured (LOWE and GARDINER 1974) were calculated. The order of importance was thus found as follows: Condylo-basal length (1), rostrum length (3), basal length (2), distance between the prosthion and the alveoli of the second pre-molars (5), palatal length (4), maximum breadth of frontals across post orbital processes (10), nose depth II (15), premaxillary length (6) , minimum inter-orbital width (11), nasal length (7) , Fl ·110

o·

o -1 00

o - 90

-aD

.+ - 70

-6

- 50L-----~------.-----~--~--~----~------~-

o

-1

-2

-3

-4

F2

Fig. 2 . The distribution of the craniometric values of red and sika deer according to the first and second canonical variate, the confidence ellipse for red deer data (the ellipse is situated higher above the abscissa) and for sika deer data (the ellipse is situated closer to the abscissa), and the relation between the level of the nasals and orbits of individual craniometric values (full point : nasals do not reach orbits; empty point: nasals reach or cross orbits)

L. BARTOS et al.: Hybridization Between Red and Sika Deer. I.

264

nose depth I (14) maximum breadth of nasals (8). palatal depth (16). maximum breadth of the brain case (12). minimum width of the maxillae (9). maximum condylar breadth (13). (The numbers in brackets are based on LOWE and GARDINER'S description.) Arithmetical means and standard errors of the first 6 variables (of 64 red deer stag skulls and 91 sika deer stag ones) are presented in Tab. 2. I

Table 1. The vector elements for two canonical axes of the analysis Craniological measure

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Condylo-basal length Basilar length Rostrum length Palatal length Distance between the prosthion and the alveoli of the second pre-molars Premaxillary length Nasal length Maximum breadth of nasals Minimum width of the maxillae Maximum breadth of frontal across post orbital processes Minimum inter-orbital width Maximum breadth of the brain case Maximum condylar breadth Nose depth I Nose depth II Palatal depth

1st axis

2nd axis

-0.0159 -0.0163 -0.0212 -0.0241

0.00027 0.00063 0.00031 0.00060

-0.0388 -0.0451 -0.0349 -0.0958 -0.0600

0.00139 0.00139 0.00132 0.00191 0.00504

-0.0392 -0.0500 -0.0770 -0.0754 -0.1059 -0.0879 -0.0839

0.00104 0.00159 -0.00072 -0.05297 0.00145 0.00221 0.01026

Table 2. Arithmetical mean and "hybrid zone" of the first six craniological measures in order of importance (in mm) craniological measure

Cervus eJaphus

(mean 1 condylo-basallength 3 rostrum length 2 basal length

± S.E.)

± 20.27 226.0,3 ± 15.34 354.02 ± 22.60 379.72

Cervus nippon

(mean

"Hybrid zone"

± S.E.)

257.19' ± 8.32

265.51 to 359.45

± 5.38 235.76 ± 7.55

140.18 to 210.69

134.80

243.31 to 331.42

5 distance between prosthion and alveoli of the 2nd pre-molars

124.48

4 palatal length

224.97

± 9.05 ± 14.16

144.48

± 3.66 ± 5.94

150.42 to 210.61

167.78

± 8.62

118.10

± 4.31

122.41 to 159.16

10 maximum breadth of frontals across post orbital processes

74.91

78.57 to 115.43

L. BARTOS et al.: Hybridization Between Red and Sika Deer. I.

Fig. 3. The shape types of the palatal bone

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L. BARTOS et al.: Hybridization Between Red and Sika Deer. L

266

The dependence of the levels of the nasals and orbits is shown in Fig. 2. Some variability was observed in the shape of the palatal bone (Fig. 3). The frequency of palatal bone shape in relation to the different levels of the nasals and orbits is indicated in Fig. 4.

NASALS REACH OR CROSS ORAL LEVEL OF ORBITS: III

::: 24 ~ 23 III 22

o ~~

em

RED DEER

:

CJ

SIKA DEER

19

;: 18 :;) 17 Z

III 15 14 13 12 II 10 9

4

I

3

2 I

NASALS DO NOT REACH ORAL LEVEL OF ORBITS: III

:)

17 ~ III III 15 14 13 IX 12 III :E 11 :;) 10 Z 9 8 7

0

...

II 5

" 3

2 I 5

II

7

8

TYPES OF PALATAL BONES

Fig. 4. The relation of the occurrence of different levels of nasals and orbits and occurrence of different types of the palatal bone

The frequency of the exterior and interior angle of the mandible in red and sika deer is shown in Fig. s.

267

L. BARTOS et aL: Hybridization Between Red and Sika Deer. 1. THE INTERIOR ANGLE OF THE MANDIBLE

'"

~35 III

is

Z30

c:t :E 25

(;

~20 III

~

15

Z

10

65

70

75

80

85

90

95

100

105

110

115

120

125

THE EXTERIOR ANGLE OF THE MANDIBLE

""~

35

~

l::::::~::::1

30

OSIKA DEER

III

c:t :E 25

RED DEER

(;

...a: 20 III

:E 15 ;:)

Z

10

65

70

75

80

85

90

95

100

105

110

115

120

125

ANGLES IN DEGREES

Fig. 5. The frequency of the exterior and interior angle of the mandible

Discussion The area defined between both confidence ellipses and between their tangents can be considered as "hybrid zone". The values of skulls of adult male deer, which would be situated within the "zone", correspond mathematically to the intermediate sika/red deer hybrid. The position of the craniometrical value of the dubious trophy gives clear evidence that this trophy, as well as twelve others (8.33% of all skulls available), belonged to a typical intermediate hybrids. The extreme values (in circle in Fig. 2) suggest that the original European red deer has been influenced by some subspecies of Cervus elaphus (e.g. mara!, wapiti and the like). In practise, to find out whether the particular skull belongs to the "hybrid" or "pure" zone, it seems to be sufficient to measure one or several more variables and to compare them to the "hybrid zone·' in Tab. 2. The more variables measured (respecting the order of importance), the better for the more objective conclusion. In the doubtful cases, when part of variables measured would be within the "hy_ brid zone" and part not, it would be necessary to count the 1st and 2nd canonical variable and to compare the results with the position in Fig. 2. The "hybrid zone" is based on skulls originated from Bohemia and Moravia. Therefore they may be applied with no doubt in these localities only. However, for the sika deer skulls, the widespreid significance within Europe is very probable.

268

L. BARTOS et al.: Hybridization Between Red and Sika Deer. 1.

The dependence of the level of the nasals and orbits shows no significant trend which would be congruent with the distribution of the craniometric values (Fig. 2). The study of the levels of the nasals and orbits was designed on the assumption derived from SOKOLOV (1959) that crossing of both species might be accompanied by a shift in the level of an aboral end: in sika deer below the level of the orbits and vice versa. However, this trait would have to be tested in representative set of skulls of the original deer species in pure form. Naturally, in evaluating the criteri~, possible manifestations of hybridization might be found in a much greater extent (Fig. 2). If this trait is of qualitative nature, it may manifest itself even at a slightest degree of hybridization. Hence it would not express the degree of hybridization but might provide information (if present in a manifestation which is not typical for a given species) that some hybridization had taken place in some generations of ancestors. This conclusion may be in agreement with the findings of hybrid phenotypes occurence (BARTOS and ZIROVNICKY 1981). As to red deer, this parameter showed different occurence in different localities during skull measurement. A lighter percentage of the occurence of this trait on the skulls (e.g. in Horsovsky Tyn region) was always connected with the revealed potential historical possibility of crossing. In the actual case of the Horsovsky Tyn hunting district this possibility was suggested by the existence of Baron Kotz's preserve in which sika deer were formerly kept together with red deer. This preserve does not exist now and the progeny of this population have merged with wild population. In sika deer the variability in the level of the nasals and orbits ("crosses or touches" and "does not cross") was also different. The variability was about the same in all the sika populations studied by us. The proportions of different shapes of the palatal bone (Fig. 3) suggest a direct dependence on the criterion of the level of the nasals in sika deer (Fig. 4). When· the nasals "touch or cross" the level of the orbits, the proportion of palatal bone No.1 is at its significant maximum (Fig. 3, 4). On the other hand, when the nasals do not "cross" or "touch" the level of the orbits, palatal bone shape NO.8 occurs most frequently. These results suggest speculation that the shape of the palatal bone might be another qualitative trait for the identification of hybrid skulls. The initial sika deer would have palatal bone shape No. 1. Shapes No.2, 3, 4, 5 would be transient, and No.6, 7 and particularly 8 would characterize red deer. Palatal shape NO.9 was found in two sika deer skulls in the Velke Mezifici game preserve. It is apparently atypical, perhaps induced by mutation. The external and internal angles measured on the mandible seem not to be useful for hybrid determination (Fig. 5). In conclusion, only the method of canonical variate analysis has brought doubtless results. On the other hand, the method of canonical variate analysis is apparently usable only for the identification of an intermediate hybrid of the Fi or perhaps F2 generation. If we admit that the hybridization is not limited to formation of Fj individuals (BARTOS and ZIROVNICKY 1981), then significant part of hybrids need not be determined by this method. In practice the presented method may be probably used successfully when judging sika deer trophies, when we may presume that the intermediate hybrids mIght belong to the strongest heads. The 13 skulls determined by the canonical variate analysis as of the hybrid origin, came almost proportionally from all the examined localities (West and Central Bohemia, Moravia). One hybrid sika deer skull was even found in the sika deer population in Velke MezifiCi game preserve, where the population has been kept separated from the red deer since nineteen fourties, accompanied by fallow

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269

deer and mouflons only. These facts as well as the result of parallel methods (BARTOS and ZIROVNICKY 1981, 1982) suggest that the hybridization between sika and red deer is more widespread within the examined localities than it was proved.

Acknowledgements We are indebted to Dr. S. MOTTL, CSc., Chief of the former Game Management Department, Research Institute of Animal Produ~tion, for making possible to perform the investigation. We wish to thank the personnel of the Ministry of Forestry and Water Management for assistance in seeking material and information. Our thanks for stimulative discussion, expert assistance and provision of material go to j. W. P LOWE and A. S. GARDINER of the Institute of Terrestrial Ecology, England, G. K. WHITEHEAD, Vice President, British Deer Society, V. E. PRISYAZHNYUK, The Central Laboratory of Nature Conservation, USSR, Dr. R. ANGERMANN and Dr. H. HACKETHAL, Humboldt University Museum of Nature Science, GDR. We are also obliged to many Czechoslovak specialists, namely to Doc. Dip!. Ing. R. SILER, DrSc. (Research Institute of Animal Production, Prague), Dr. Dipl. lng. L. DOBRORUKA (Prague Zoological Garden), Dipl. Ing. j. VAVRUNEK, Chairman of the Advisory Board for the Sika Deer Area, Plzeii., Dr. V. MAZAK, National Museum, Prague, and a number of other experts.

Zusammenfassung Bei der Erforschung der Hybridisation zwischen europaischem Rothirsch und Sikahirsch in ausgewahlten Gebieten der Tschechoslowakei wurden einige Parallelmethoden verwendet. Bei der Beurteilung der Schadel war es: Bearbeitung der kraniometrischen Angaben durch kanonische Faktoranalyse; das Verfolgen der Lage von Nasenbeinen zu Augesprossen; Verfolgen der Form des Gaumenbeins und Messung von auf3eren und inneren Winkeln der Kiefer. Durch das Ausrechnen von Konfidenzellipsen wurde die "Hybridzone" in graphischer Veranschaulichung der Werte der ersten und zweiten kanonischen Zufallsvariablen mathematisch definiert. Mathematisch wurden Kriterien abgeleitet, nach denen es moglich ist, in der Praxis (durch Messung einer oder mehreren kraniologischen Maf3e) den Schadel des intermediaren Hybrids von den Schadeln der "reinen" Individuen der Cerviden der Ausgangsarten zu unterscheiden. Die Nasenbeinlage und die Form des Gaumenbeins werden als mogliche Folgen der Hybridisierung diskutiert. Einzelne zwischenartliche Hybride wurden in allen erforschten Lokalitaten (West- und Mittelbohmen, Mahren) nachgewiesen. Die festgestellten Ergebnisse deuten an, daf3 die zwischenartliche Kreuzung des europaischen Rothirsches mit dem Sikahirsch im Rahmen der erforschten Gebiete weit verbreitet sein konnte.

References ANTONIUS, 0.: Verh. Zool.-bot. Ges. Wien 92 (1951) 106-115. Cited by STEKLENEV (1969). BARTOS, L., and j. ZIROVNICKY: Hybridization between red and sika deer. II. Phenotype analyses. Zool. Anz., lena 207 (1981) 271-287. -: Hybridization between red and sika deer. III. Interspecific behaviour. Zool. Anz., lena 208 (1982) (in press). -, M. HYKSOvA and L. POLAKovA: Hybridizace siky (Cervus nippon Temm.) s jelenem evropsk-im (Cervus elaphus L.). Closing report. Prague: Research Institute of Animal Production 1978.

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-, -, -: V-yskyt znaku kfizeni jelena evropskeho se sikou u ulovene zvere vybranych oblasti. Closing report. Prague: Research Institute of animal production 1979. BENNETSEN, E.: Some facts about sika deer in Denmark. Deer 4 (1977) 153-157. BLACKITH, R. E., and R. A REYMENT: Multivariate morphometrics. London, New York: Academic Press 1971. DELAP, P.: Hybridization of red and sika deer in North-West England. Deer 1 (1967) 131133. -: Observations on deer in North-West England. J. Zoo1. 156 (1968) 531-533. FLEROV, K. K.: Fauna SSSR. Tom 1, (2) Kabargi. i oleni. Moskva, Leningrad : Izdatelstvo Akademii Nauk SSSR 1952. GEPTNER, V. G., A A NASIMOVICH i A G. BANJKOV: Mlekopitayushchie Sovetskogo soyuza. Tom perviy. Parnokopytnye i neparnokopytnye. Moskva: Gosudarstvennoe Izdatelstvo "Vysshaya shkola" 1961. HARRINGTON, R. (1973): Hybridization among deer and its implications for conservation. Ir. For. J. 30 (1973) 64-78. LOWE, V. P. W., a nd A S. GARDINER: A re-examination of the subspecies of red deer (CerDUS elaphus) with particular reference to the stocks in Britain. J. Zoo1. 174 (1974) 185-201. -, -: Hybridization between red deer (Cervus elaphus) and sika deer (Cervus nippon) with particular reference to stocks in N.W. England. J. Zoo1. 177 (1975) 553-556. MIROLYUBOV, I. I.: Gibridizaciya pyatnistogo olenya s izyubrem. Karakulevodstvo i Zverovodstvo 1 (1949) 74-75. MOFFAT, C. B.: Mammals of Ireland. Dublin: Hodges, Figgis & Co. 1938. RocHoLL, W.: Gebt "griines Licht" fUr Sika-Wild. Wild und Hund (1967) 134-137. SALGANSKIY, A A, 1. S. SLES, V. D. TREUS i G. A USPENSKIY: Zoopark "Askaniya Nova" (Opyt akklimatizacii dikich kopytnykh i strausov). Kiev: Gosozdat S.-Kh. Literatury USSR 1963. SARKISOV, A A: Tr. Jerevansk. Zoo1. Parka 1-2 (1944) 91-97. Cited by SOKOLOV (1959) . STEKLENEV, E. P. (1969): Genetika i selekciya tvarin. Vid-vo "Naukova Dumka" (1969) 111-113. WETTSTEIN, 0.: Zwei Rot-Sikawild-Bastarde aus freier Wildbahn. Z. Saugetierkd. 6 (1931) 177-285. WHITEHEAD, G. K.: The deer of Great Britain and Ireland. London: Routledge & Kegan Paul 1964. LUDEK BARTOS and JAROMIR HyANEK, Department of Genetics, Research Institute of Animal Production, CS-251 61 Praha 10-Uhfineves (Czechoslovakia) JIiH ZIROVNICKY, Game Management Department, Research Institute of Forestry and Game Management, CS-255 01 Jl1oviste-Strnady (Czechoslovakia)