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Likeness between the food habits of European wildcats, domestic cats and

their hybrids in France

Estelle Germaina,b, Sandrine Ruettec, Marie-Lazarine Poullea,b,�

aLaboratoire de Parasitologie-Mycologie, EA 3800, IFR 53, UFR Medecine, Universite de Reims Champagne-Ardenne,

51 rue Cognacq-Jay, 51096 Reims, Franceb2C2A-CERFE, 5 rue de la Heronniere, 08240 Boult-aux-Bois, FrancecONCFS, CNERA PAD, Montfort, 01330 Birieux, France

Received 28 November 2007; accepted 28 May 2009

Keywords: European wildcat; Domestic cat; Hybrid; Food habits; Felis silvestris

The European wildcat, Felis s. silvestris Schreber,1777, is considered as an endangered species and isstrictly protected under Annexe IV of the EuropeanHabitat Directive (92/43/EEC). This wild felid can breedwith the domestic cat, Felis catus L. to produce fertilehybrids (Ragni 1993). These hybrids may be responsibleof the introduction of domestic cat’s genes into thewildcat populations (i.e. introgression) when breedingwith wildcats (Beaumont et al. 2001). Hybridization andintrogression are thus considered as a potential threatfor the European wildcat since they compromise thegenetic integrity of their populations (Beaumont et al.2001; Pierpaoli et al. 2003; Lecis et al. 2006).

The importance of hybridization and introgression inwildcat populations differed in a large extent from oneEuropean country to another (see Randi et al. 2001;Beaumont et al. 2001; Pierpaoli et al. 2003; Lecis et al.2006; Oliveira et al. 2007; O’Brien et al. 2009). Pierpaoliet al. (2003) assumed that the reasons of suchgeographical differences are historic, demographic andecologic. However, the respective influence of each ofthese factors is still unknown.

From an ecological point of view, as food foraginginfluences spatial and temporal segregation between

atter r 2009 Deutsche Gesellschaft fur Saugetierku09.05.008

r at: 2C2A-CERFE, 5 rue de la Heronniere,rance.

elazarine.poulle@cerfe.com (M.-L. Poulle).

species (Schoener 1986), the opportunities of meetingsbetween wildcats, hybrids and domestic cats – thatinfluence the risks of hybridization and introgression –may depend in a large part on the importance of thelikeness between their food habits. Data on the degree ofoverlap between their diets could thus provide usefulinformation on the chance they have to meet while dataon the type of food item they share could provideinformation on the type of habitat where the meetingsmay occur.

The diet of the European wildcat has been examinedin various countries like in France, Spain, Portugal,Scotland, Slovakia and Hungary. It varies according toprey availability (Moleon and Gil-Sanchez 2003; Maloet al. 2004; Lozano et al. 2006). Indeed, it includesmainly small mammals such as meadows and forestrodents (Conde et al. 1972; Stahl 1986; Riols 1988;Sarmento 1996; Tryjanowski et al. 2002; Biro et al. 2005)but rabbits are preferred where available (Corbett 1979;Aymerich 1982; Gil-Sanchez et al. 1999). The Europeanwildcat is thus considered as a facultative specialistcarnivore (Moleon and Gil-Sanchez 2003; Malo et al.2004; Lozano et al. 2006). In contrast, the free rangingdomestic cat is considered as a generalist and opportu-nist one because its diet may include as well small-sizemammals as birds, amphibians, insects and anthropo-genic food (review in Fitzgerald 1988). The food habitsof hybrids have only been explored in Hungary by Biro

nde. Published by Elsevier GmbH. All rights reserved.

Mamm. biol. 74 (2009) 412–417

ARTICLE IN PRESSE. Germain et al. / Mamm. biol. 74 (2009) 412–417 413

et al. (2005). These authors found that the compositionof hybrids diet was intermediate between those ofwildcats and feral domestic cats but closer to the wildcatone.

The aim of the present study was to evaluate thelikeness between the food habits of wildcats, domesticcats and hybrids in France by comparing their degree ofspecialization and by estimating their trophic nicheoverlap. Attempts have also been made to identify thehabitat where the meetings may occur (meadows/forests/human settlements) from the one of the fooditems they share.

Food habits were assessed through the identificationof undigested remains found in the stomachs of 59 road-killed adult cats collected from 2001 to 2006 in theFrench range area of the European wildcat (Leger et al.2008; Fig. 1). Cats were collected by the French Huntingand Wildlife Office (ONCFS) rangers at any time of theyear. They were genetically identified (see O’Brien et al.2009). Stomachs were collected during autopsies andthen decontaminated at �80 1C before being defrostedand washed in water above a sieve (mesh size: 500 m).The identification of undigested remains was conductedfrom feathers for birds, from bones and skins foramphibians and from chitin shells for insects. The

0 80 160 Kilometers

Fig. 1. Locations of the European wildcats (n ¼ 26), the hybrids (n

Hunting and Wildlife Office (ONCFS) rangers from 2001 to 2006 in

identification of mammal species was first based on thegeneral aspect of the undigested remains (size of thecorpse, of the tail, of the ears) or on the microscopicexamination of hairs medulla to distinguish rodents orinsectivores from lagomorphs, ungulates or carnivores.Then, the macroscopic examination of teeth associatedwith the microscopic examination of cross-section ofhair (plate method) was used to identify rodents andinsectivores species by comparison to the characteristicsdescribed by Keller (1981a–c), Debrot et al. (1982) andErome and Aulagnier (1982). Results were expressed interm of relative occurrences.

As recommended by Fritts and Mech (1981) andCiucci et al. (1996), we assessed our accuracy inidentifying small mammal hairs and teeth with a blindtest. This test was conducted on 34 samples of hairs and/or teeth of small-size mammals (field voles Microtus

spp., water voles Arvicola terrestris, field mice Apodemus

spp., bank voles Clethrionomys glareolus, garden dor-mice Eliomys quercinus, house mice Mus musculus,norway rats Rattus norvegicus, muskrats Ondatra

zibethicus, shrews Sorex spp. and moles Talpa europaea).Reported accuracy in the examination of teeth (accom-panied or not with hairs of the same individual) was of100%, whereas it was of only 30% for the examination

N

European wildcats locations

European wildcats range area in France (Léger et al. 2008)

Domestic cats locations

Hybrid cats locations

French administrative superficies divisions

¼ 19) and the domestic cats (n ¼ 14) collected by the French

North-eastern France.

ARTICLE IN PRESSE. Germain et al. / Mamm. biol. 74 (2009) 412–417414

of hairs alone. For that reason, food remains onlyidentified on the base of hairs examination wereconsidered as ‘‘unidentified small-size mammals’’.

A G-test with simulated p-value (Monte Carlosimulation based on 10,000 replicates) was used to testthe homogeneity of the distribution of cats collectedunder seasons (spring, summer, autumn and winter).The same test was used to compare the distributions ofthe food items found in the stomachs of the three typesof cats. The standardized niche breadth index of Levins(1968 in Krebs 1999) was used to compare the degree offood habits specialization per types of cat, by taking intoaccount the four food categories considered by Stahl(1986), Fitzgerald (1988) and Biro et al. (2005): ‘‘small-size mammals’’, ‘‘birds’’, ‘‘other animals’’ (amphibians,insects) and ‘‘human-linked food’’. The index of Levinswas calculated as follow: BA ¼ (B�1)/(n�1) with B ¼ 1/P

pj2 where pj is the fraction of food items that are of

food category j and n is the number of food categoriesrepresent. This index ranges from 0 (very specializedfood habits) to 1 (very generalist food habits). Thedegree of similarities between the food habits ofwildcats, domestic cats and hybrids was also estimatedby using the Niche overlap index Ojk ¼ [

Ppij pik ]/

[O(P

pij2Ppik

2) ], where j and k are the taxa compared,pij and pik are the proportions of the ith food item usedby the species j and k respectively (Pianka 1973). TheNiche overlap index ranges from 0 (no overlap) to 1 (fulloverlap).

The stomachs of 26 wildcats, 19 hybrids and 14domestic cats were examined. The number of catscollected was homogeneously distributed into the fourseasons (P ¼ 0.74) and the distribution of the number ofcats collected per seasons did not differed according tothe type of the cats (P ¼ 0.77; Fig. 2).

10

9

8

7

6

5

4

3

2

1

0

Num

ber

of c

ats

colle

cted

SPRING SUMMER

WildHybrDom

Fig. 2. Number of wildcats, hybrids and domestic cats collecte

A total of 40, 36 and 25 food items belonging to 10, 11and 9 different types of food were respectively found inwildcats, hybrids and domestic cats (Table 1). Fooditems from meadows (e.g. Microtus spp. and Arvicola

terrestris), forests (e.g. Apodemus spp. and Clethrion-

omys glareolus) and human-settlements (e.g. Mus

musculus, poultry and pet or human-linked food) werefound in the stomachs of each type of cats (Table 1).

The distribution of the food items significantlydiffered according to the type of the cats (P ¼ 0.002;Fig. 3). Small-sized mammals were the more frequentfood item whatever the types of the cats. They werepresent in 90%, 64% and 52% of the stomachs ofwildcats, hybrids and domestic cats respectively. Forestrodents were more frequent in wildcat and hybridstomachs than in domestic cat ones (Fig. 4). Birds(Passeriformes spp.) were present in 1 to 4 stomachs pertype of cats (Table 1). The occurrences of other animals(insects and amphibians) and the occurrences of human-linked food were similar in the stomachs of hybrids(respectively 9% and 25%) and domestic cats (respec-tively 4% and 36%) whereas they were absent in thewildcat stomachs.

Domestic cats had the broadest standardized trophicniche (BA domestic cats ¼ 0.48) followed by hybrids (BA

hybrids ¼ 0.36) and then, by wildcats (BA wildcats ¼ 0.22).The trophic niche of hybrids was closer to the one ofdomestic cats (0.88) than to the one of wildcats (0.74),wildcats and domestic cats having the less overlappingtrophic niche (0.46).

According to Biro et al. (2005), our results suggest animportant likeness between the food habits of wildcats,hybrids and domestic cats with regard to their frequentpredation on small-sized mammals (rodents and insecti-vores). This likeness is more particularly evident

AUTUMN WINTER

catsidsestic cats

d per season in North-eastern France from 2001 to 2006.

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Table 1. Number (n) of stomachs of wildcats, hybrids and domestic cats containing the different food items and frequency of

occurrence (%) of these items relatively to the total number of occurrences.

Wildcats Hybrids Domestic cats

Categories Food items n % n % n %

Small-size mammals Field vole Microtus spp. 5 13 5 14 4 16

Water vole Arvicola terrestris 1 3 0 0 0 0

Field mouse Apodemus spp. 13 33 6 17 1 4

Bank vole Clethrionomys glareolus 4 10 3 8 0 0

Edible dormouse Glis glis 1 3 0 0 0 0

House mouse Mus musculus 2 5 1 3 2 8

Norway rat Rattus norvegicus 0 0 1 3 0 0

Shrew Sorex spp. 1 3 0 0 1 4

Mole Talpa europaea 1 3 0 0 0 0

Unidentified small-size mammals 8 20 7 19 5 20

Birds Passeriformes spp. 4 10 1 3 2 8

Other animals Insects (Crickets) 0 0 2 6 1 4

Amphibians (Frog spawn, lizard) 0 0 1 3 0 0

Human-linked food Pet food and human food 0 0 8 22 8 32

Poultry 0 0 1 3 1 4

Total 40 100 36 100 25 100

80%

100%

60%

40%

20%

0%Wildcats Hybrids Domestic cats

Human-linked food

Other animalsBirds

Small-size mammals

Rel

ativ

e oc

curr

ence

s

Fig. 3. Relative occurrences of small-size mammals, birds, other animals and human-linked food in the stomachs of wildcats

(n ¼ 26), hybrids (n ¼ 19) and domestic cats (n ¼ 14) collected in North-eastern France from 2001 to 2006.

E. Germain et al. / Mamm. biol. 74 (2009) 412–417 415

between hybrids and domestic cats as they also eatamphibians, insects and human-linked food. However,by contrast with Biro et al. (2005) results, we found thehybrids being at an intermediate degree of specializationbetween wildcats (narrowest trophic niche) and domes-tic cats (broadest trophic niche) but with food habitscloser to the ones of domestic cats than to wildcat foodhabits. This observation let supposed that, in North-eastern France, hybrids and domestic cats may havemore chance to meet than wildcats and domestic catshave.

Since hybrids seemed to consume more frequentlyforest than meadow rodents as wildcats do, these twotypes of cats have more chance to meet in forest than inmeadow. Wildcats and hybrids may also approachhuman settlements as indicated by the occurrence ofhouse mice in their stomachs. In Hungary, Biro et al.(2005) found Mus musculus only in the stomachs ofhybrids and domestic cats while in France we found it inthe stomachs of the three types of cats. This confirms theresults of Germain et al. (2008) who located radio-tracked wildcats and hybrids near farms and villages.

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80%

100%

60%

40%

20%

0%Wildcats Hybrids Domestic cats

Rel

ativ

e oc

curr

ence

sForest rodents

Meadow rodents

Fig. 4. Relative occurrences of forest rodents (Apodemus spp. and Clethrionomys glareolus) and meadow rodents (Microtus spp. and

Arvicola terrestris) in the stomachs of wildcats (n ¼ 26), hybrids (n ¼ 19) and domestic cats (n ¼ 14) collected in North-eastern

France from 2001 to 2006.

E. Germain et al. / Mamm. biol. 74 (2009) 412–417416

Nevertheless, considering the relative occurrence ofhuman-linked food in the stomachs of hybrids anddomestic cats, meetings in the vicinity of humansettlements may the most probably involved hybridsand domestic cats. Further investigations are needed tosee how similarities between food habits may reallycontribute to meetings – and thus potential interbreed-ings – between the three types of cats.

Acknowledgements

The authors are very grateful to Francois Leger andto the French Hunting and Wildlife Office’s rangers forcollecting cat corpses, to the persons who participate tothe autopsies and to the stomach analysis, especiallyKevin Georgin. The authors also sincerely thank CelineSimon for improving the English version. Financial andlogistic support for this study was provided by theFrench Hunting and Wildlife Office, the UMR CNRS5558 ‘‘Biometrie et Biologie Evolutive’’, the ‘‘ConseilGeneral des Ardennes’’, the ‘‘Communaute de Commu-nes de l’Argonne Ardennaise’’ and the ‘‘Zoo d’Amne-ville’’ (Moselle, France). All the statistical analysis wasperformed using R 2.8. free software (www.r-project.org).

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