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Scien i ic RepoR s | 6:20552 | DOI: 10.1038/s ep20552
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Human beha iou can igge la ge
ca ni o e a acks in de eloped
coun ies
Vincenzo Pen e iani1,2, Ma ía del Ma Delgado2,3, F ancesco Pinche a4, Ja ie Na es1,
Albe o Fe nández-Gil1, Ilpo Kojola5, Sauli Hä könen6, Ha i No be g6, Jens F ank7,
José Ma ía Fed iani1,8, Ve onica Sahlén9,10, Ole-Gunna S øen9, Jon E. Swenson9,10,
Pe e Wabakken11, Ma io Pelleg ini4, S ephen He e o12 & José Vicen e López-Bao2,7
The media and scien i ic li e a u e a e inc easingly epo ing an escala ion o la ge ca ni o e a acks on
humans in No h Ame ica and Eu ope. Al hough a e compa ed o human a ali ies by o he wildli e,
he media o en o e play la ge ca ni o e a acks on humans, causing inc eased ea and nega i e
a i udes owa ds coexis ing wi h and conse ing hese species. Al hough la ge ca ni o e popula ions
a e gene ally inc easing in de eloped coun ies, inc eased numbe s a e no solely esponsible o he
obse ed ise in he numbe o a acks by la ge ca ni o es. He e we show ha an inc easing numbe
o people a e in ol ed in ou doo ac i i ies and, when doing so, some people engage in isk-enhancing
beha iou ha can inc ease he p obabili y o a isky encoun e and a po en ial a ack. Abou hal o
he well-documen ed epo ed a acks ha e in ol ed isk-enhancing human beha iou s, he mos
common o which is lea ing child en una ended. Ou s udy p o ides unique insigh in o he causes,
and as a esul he p e en ion, o la ge ca ni o e a acks on people. P e en ion and in o ma ion ha
can encou age app op ia e human beha iou when sha ing he landscape wi h la ge ca ni o es a e
o pa amoun impo ance o educe bo h po en ially a al human-ca ni o e encoun e s and hei
consequences o la ge ca ni o es.
Du ing he las ew decades, la ge ca ni o e a acks on humans in de eloped coun ies ha e inc eased o e ime1–8
(Fig.1). This is expec ed o inc ease people’s app ehension and educe hei willingness o sha e he landscape
wi h la ge ca ni o es. Un o una ely, such a e e en s a e usually o e played by he media. Indeed, media co e -
age o such a acks gene ally includes sensa ional ex s and d ead ul pic u es (Ex ended Da a 1), appealing mo e
o he public’s emo ions han hei logic. Denomina o neglec 9 is a well-s udied phenomenon leading humans o
o e es ima e he isk o a e e en s ha e oke s ong emo ions. O e es ima ing he isk o la ge ca ni o e a acks
on humans i a ionally enhances human ea and igge s a icious cycle ha may a ec he inc easingly posi-
i e conse a ion s a us o many o hese con en ious species10–12. Wi h an inc easing numbe o la ge ca ni o e
a acks on humans he e is, now mo e han e e , a need o objec i e and accu a e in o ma ion ega ding no
only he long- e m end and unde lying mechanisms o la ge ca ni o e a acks on humans, bu also po en ially
isky si ua ions and isk-enhancing human beha iou s8. Su p isingly, he ew a ailable s udies ocus on a acks by
1Depa men o Conse a ion Biology, Es ación Biológica de Doñana, C.S.I.C., c/Amé ico Vespucio s/n, 41092 Se ille,
Spain. 2Resea ch Uni o Biodi e si y (UMIB, UO-CSIC-PA), O iedo Uni e si y-Campus Mie es, 33600 Mie es, Spain.
3Me apopula ion Resea ch Cen e, Uni e si y o Helsinki, FI-00014 Helsinki, Finland. 4C.I.S.D.A.M., Via S. Libe a a
1, Rosello (CH) I-66040, I aly. 5Na u al Resou ces Ins i u e Finland, P.O. Box 16, FI-96301 Ro aniemi, Finland.
6Finnish Wildli e Agency, Sompion ie 1, FI-00730 Helsinki, Finland. 7G imsö Wildli e Resea ch S a ion, Depa men
o Ecology, Swedish Uni e si y o Ag icul u al Sciences, 73091 Ridda hy an, Sweden. 8Cen e o Applied Ecology
“P o . Bae a Ne es”, Ins i u e Supe io o Ag onomy, Uni e si y o Lisbon, Tapada da Ajuda, 1349-017 Lisboa,
Po ugal. 9Depa men o Ecology and Na u al Resou ce Managemen , No wegian Uni e si y o Li e Sciences,
Pos box 5003, NO-1432 Ås, No way. 10The No wegian En i onmen Agency, P.O. Box 5672 Sluppen, N-7485
T ondheim, No way. 11Facul y o Applied Ecology and Ag icul u al Sciences, Hedma k Uni e si y College, E ens ad,
NO-2480, Koppang, No way. 12Facul y o En i onmen al Design, Uni e si y o Calga y, Calga y, Albe a, Canada T2T
2Y2. Co espondence and eques s o ma e ials should be add essed o V.P. (email: [email p o ec ed])
Recei ed: 27 July 2015
Accep ed: 06 Janua y 2016
Published: 03 Feb ua y 2016
OPEN
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Scien i ic RepoR s | 6:20552 | DOI: 10.1038/s ep20552
single ca ni o e species and hus hey do no p o ide a comp ehensi e pe spec i e conce ning he pe asi eness
and socio-ecological co ela es o his phenomenon in de eloped coun ies.
Ou main hypo hesis is ha lack o knowledge o people abou how o a oid isky encoun e s wi h la ge ca -
ni o es engende s isk-enhancing beha iou s, which can de e mine an inc ease in he numbe o a acks i mo e
humans a e sha ing landscape wi h la ge ca ni o es. Th ee main p edic ions a ise om his hypo hesis: (1) an
inc eased numbe o people a e engaging in ou doo leisu e ac i i ies in a eas inhabi ed by la ge ca ni o es; (2)
many people a e no p epa ed o sa ely enjoy ou doo ac i i ies o hey beha e inapp op ia ely in he coun yside;
and (3) la ge ca ni o e a acks a e in luenced by he in e ac ion be ween se e al human- and animal- ela ed
ac o s.
Thus, we i s explo ed whe he he long- e m pa e ns in he numbe o a acks ha e been simila among di -
e en la ge ca ni o e species, and how hey a ied h oughou he yea . Then, we e alua ed whe he he e migh
ha e been a gene al long- e m change in he a ack pa e ns by assessing whe he ic im ages and he equency
o a acks on pa ies s. lone humans ha e changed in a cong uen manne o he di e en species. Finally, we
assessed he possible ela ionships be ween empo al ends o a acks on humans and ou doo ac i i ies, as well
as he ole ha isk-enhancing human beha iou can ha e played in he obse ed inc ease in la ge ca ni o e
a acks.
Figu e 1. Tempo al ends in la ge ca ni o e a acks on humans in de eloped coun ies. The numbe
o a acks on humans by la ge ca ni o es has inc eased signi ican ly (Ex ended Da a Table 1) du ing he las
ew decades o almos all la ge ca ni o es. The le panel shows he ela ionship be ween he numbe o la ge
ca ni o e a acks in he US and he numbe o isi o s (hund eds o millions, ed line) in Ame ican p o ec ed
a eas since 1955, which has inc eased signi ican ly o e ime (Ex ended Da a Table 4). The igh panels show
( om op o bo om) he empo al ends in la ge ca ni o e a acks in Canada, as well as he ends o pola
bea (Eu ope, Russia, he Uni ed S a es and Canada) and Eu opean b own bea (Sweden, Finland and Spain)
a acks. I is wo h no ing ha : (i) con lic s wi h pola bea s ha e been inc easing in he las decade. Causal
ac o s include a g owing human popula ion and mo e ou is s isi ing pola bea a eas, inc eased oil and gas
de elopmen along he A c ic coas line, and dec easing ice olume and seasonal ex en due o clima e change63.
Indeed, human-pola bea encoun e s a e expec ed o inc ease as he sea ice con inues o mel and hung y
bea s a e d i en asho e (h p://www.pola bea sin e na ional.o g/abou -pola -bea s/essen ials/a acks-and-
encoun e s; h p://www. hegua dian.com/wo ld/2013/no /04/pola -bea -a acks-scien is s-wa n-wa ming-
a c ic); (ii) he ema kable inc ease in coyo e a acks may be ela ed o bo h he ecen subs an ial expansion
o he coyo e ange in eas e n No h Ame ica64 and inc eased con lic s in subu ban esiden ial a eas. In hese
a eas, coyo es can elax human a oidance mechanisms as a esul o elying on an h opogenic ood esou ces
and e en in en ional eeding by esiden s4; and (iii) wol es we e he only species o show a dec easing end in
he numbe o a acks, declining om 10 a acks du ing he decade 1975–1984 o only wo o h ee a acks pe
decade s a ing in 1985. (The b own bea pic u e has been downloaded om 123RF ROYALTY FREE STOCK
PHOTOS (h p://www.123 .com), Image ID 7250879, E ic Isselee).
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Scien i ic RepoR s | 6:20552 | DOI: 10.1038/s ep20552
We analysed he ci cums ances o ca. 700 la ge ca ni o e a acks on people om 1955 in de ail (when mo e
eliable da a became a ailable) un il he p esen o six species esponsible o mos o he la ge ca ni o e a acks
eco ded in No h Ame ica and Eu ope: b own/g izzly bea U sus a c os, black bea U sus ame icanus, couga
Puma concolo , wol Canis lupus and coyo e Canis la ans in No h Ame ica, b own bea in Eu ope, and pola
bea U sus ma i imus ci cumpola , i.e. Eu ope, Russia and No h Ame ica. We also collec ed s a is ics conce ning
ou doo ac i i ies du ing he same pe iod (see Me hods o mo e de ails).
The numbe o la ge ca ni o e a acks on people has inc eased signi ican ly o e ime, wi h con as ing ends
ac oss species (Fig.1; Ex ended Da a Table 1). In No h Ame ica, coyo es (31.0% o he o al numbe o a acks)
and couga s (25.7%) we e esponsible o he majo i y o a acks, ollowed by b own bea s (13.2%), black bea s
(12.2%) and wol es (6.7%). A simila inc ease o e ime was obse ed o b own bea s (9.3%) in Eu ope and ci -
cumpola o pola bea s (1.9%; Fig.1). Mo eo e : (a) he age o ic ims has also inc eased signi ican ly o e ime
showing di e en pa e ns ac oss species (Ex ended Da a Table 2 and Ex ended Da a Fig.1); and (b) he p open-
si y o a ack lone humans o pa ies depends on he la ge ca ni o e species, and only a sligh bu non-signi ican
inc easing end o a acks on pa ies has been obse ed (Ex ended Da a Table 3 and Ex ended Da a Fig.2A,B).
The pa e ns o a acks epo ed he e may also e lec an inc easing numbe o bold indi iduals in la ge ca ni-
o e popula ions, as his ai is o en co ela ed wi h agg essi eness13,14, and his migh lead o mo e agg essi e
esponses when la ge ca ni o es encoun e humans. We hypo hesise ha in ense and p olonged human-caused
mo ali y imposes selec ion p essu es on a ge popula ions (selec i e emo al o ce ain pheno ypes) and migh
lead o apid e olu iona y changes15. Na u al selec ion main ains a mix o beha iou al pheno ypes in popula-
ions16, he shy-bold beha iou al con inuum17; bold indi iduals h i e on isk and no el y, whe eas shy indi idu-
als sh ink om he same si ua ions18. Pe secu ion, howe e , is expec ed o esul in he disp opo iona e emo al
o bold indi iduals, as hey a e less cau ious19, and hus mo e likely o be killed. As a consequence, shy indi id-
uals migh ha e been o e ep esen ed in emnan la ge ca ni o e popula ions in he pas 17,18,20–22. Addi ionally,
indi iduals may become mo e igilan and ac i ely a oid con ac wi h humans du ing imes o in ense pe secu-
ion23. Al hough he his o y o la ge ca ni o e pe secu ion and conse a ion di e ac oss egions9, he con empo-
a y conse a ion pa adigm eme ged du ing he 1960s–1970s24, when mos boun y sys ems we e banned25 and
la ge ca ni o es we e eclassi ied om e mins o boun ied p eda o s o game o p o ec ed species. Since hen,
al hough la ge ca ni o es ha e con inued o be hun ed o managed (Ex ended Da a Fig.3), mos popula ions
ha e gene ally inc eased du ing he pas ou decades9,11,12. Inc easing popula ion ends in conjunc ion wi h
elaxed a i icial selec ion may po en ially engende highe a ia ion in beha iou al empe amen s26, which is
likely o al e indi idual esponses o human encoun e s22. This signi ican inc ease o la ge ca ni o e popula ions
in bo h No h Ame ica and Eu ope, and hei consequen ange expansion, also may con ibu e o explain he
obse ed inc ease in he a acks on humans.
Howe e , simila o he inc easing end in a acks, he numbe o people engaging in ou doo leisu e ac i i ies
also has isen o e ime, a phenomenon ha is signi ican ly co ela ed wi h he obse ed end in he numbe
o a acks (Fig.1; Ex ended Da a Table 4, Ex ended Da a Fig. 4A–C). Seasonally, mos o he a acks occu ed
be ween la e sp ing and ea ly au umn (Fig.2), when mos people pu sue ou doo ac i i ies7,8; in addi ion, because
bea s hibe na e, hey a e unlikely o a ack people in win e . Such an inc ease in ec ea ional ac i i ies in a eas
inhabi ed by la ge ca ni o es implici ly inc eases he p obabili y o a isky encoun e and, he e o e, a po en ial
a ack. Howe e , e en wi h mo e people isi ing hose a eas, a acks a e s ill ex emely a e (Fig.1): al hough
some people may only ocus on he o al numbe o a acks, we ha e o bea in mind he long ime pe iod du ing
which hese a acks occu ed.
Figu e 2. Tempo al ends in la ge ca ni o e a acks on humans in de eloped coun ies: mon hly pa e ns.
Mos la ge ca ni o e a acks occu ed om la e sp ing o ea ly au umn, when mos people usually engage in
ou doo ac i i ies. (The coyo e pic u e has been downloaded om 123RF ROYALTY FREE STOCK PHOTOS
(h p://www.123 .com), Image ID 14988151, James Ma il).
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Scien i ic RepoR s | 6:20552 | DOI: 10.1038/s ep20552
Rema kably, isk-enhancing human beha iou has been in ol ed in a leas hal o he well-documen ed
a acks (47.6%; Fig.3). F om highes o lowes , he i e mos common human beha iou s occu ing a he ime o
an a ack we e (a) pa en s lea ing child en una ended, (b) walking an unleashed dog, (c) sea ching o a wounded
la ge ca ni o e du ing hun ing, (d) engaging in ou doo ac i i ies a wiligh /nigh and (e) app oaching a emale
wi h young. These a e clea ly isk-enhancing beha iou s when sha ing he landscape wi h la ge ca ni o es. Fo
example, he mos equen ly eco ded human beha iou was child en le una ended (47.3%), which we e mos
o en a acked by couga s (50.8% o he a acks), coyo es (27.9%) and black bea s (13.2%). Risk-enhancing human
beha iou is no he sole eason behind la ge ca ni o e a acks on humans. The causes o he o he hal o he
a acks do no seem o be ela ed o isk-enhancing human beha iou , o example, acciden ally walking close o a
mo he wi h young o o a ca cass wi h a bea nea by o an encoun e wi h a ood-condi ioned indi idual (which
is an indi ec esul o a isk-enhancing human beha iou 8).
Thousands o in e ac ions occu be ween people and la ge ca ni o es wi h no human inju ies o a ali ies.
E en i a acks ha e inc eased o e ime, hey emain ex emely a e e en s (e.g. a c oss-con inen al a e age o
24.1 a acks and 3.9 a ali ies pe yea du ing he las decade, all species pooled; Fig.1). O he wildli e (bees and
mosqui os, spide s, snails, snakes and ungula es) and domes ic dogs a e a mo e esponsible o human a ali-
ies1,27. Bu humans a e no he only ic ims. When a acks occu , la ge ca ni o es a e equen ly killed and nega-
i e a i udes owa ds la ge ca ni o es ha den6. Le hal emo al o ‘p oblema ic’ indi iduals is e ec i e in sol ing
he local p oblem caused by a gi en indi idual28, bu gene ally his happens a e an agg essi e beha iou , human
inju y o dea h has occu ed. Consequen ly, bo h humans and ca ni o es su e om hese inciden s.
A e decades o minimal in e ac ion be ween humans and la ge ca ni o es in many egions o de eloped
coun ies, many people in ol ed in ou doo ac i i ies may lack knowledge abou how o a oid isky encoun e s
wi h la ge ca ni o es and wha o do when such encoun e s occu . F om an ea ly age mos o us lea n social
no ms, ules and how o dec ease isks in u ban en i onmen al se ings, bu much less e o is expended o
each us how o sa ely enjoy ou doo ac i i ies o o beha e app op ia ely in he coun yside. Howe e , i is up
o us o educe he likelihood o an a ack. The inc easing human p esence in a eas inhabi ed by la ge ca ni-
o es, oge he wi h hei popula ion eco e ies9,11,12, equi es an imp o emen in in o ma ion, educa ion and
p e en ion guidelines, and hei en o cemen , which a e o pa amoun impo ance o educe bo h he isks o
humans and he killing o ca ni o es1,4,7,28,29. Educa ing people ha sha e landscape wi h la ge ca ni o es can
ep esen a c ucial ac o o help educing he numbe o a acks and also he nega i e a i udes owa ds la ge
ca ni o e conse a ion, especially because o he di icul y o en isage isk es ima es. Indeed, scena ios o a acks
a e ex emely di e en and may depend on many di e en ac o s, such as human popula ion and ca ni o e
densi ies, ime o he day, human ac i i ies, pe sonali y and condi ion o he la ge ca ni o e, pa y size o e en
sub le de ails, like he p esence o an unleashed dog a he momen o he a ack and/o he landscape ea u es o
he a ea whe e an a ack has happened. As con lic s be ween humans and la ge ca ni o es con inue o inc ease,
accu a e in o ma ion becomes c ucial o in o med human–wildli e con lic managemen . Communica ing abou
la ge ca ni o e-in lic ed human inju ies and a ali ies in a s a is ical manne con ibu es o be e unde s anding
o common pa e ns in la ge ca ni o e a acks, u he educes chances o inju y o dea h and p omo es public
app ecia ion o hese species. An impo an s a egy o educe a acks on humans is o in o m people how o a oid
Figu e 3. The numbe o a acks is modula ed by human beha iou . A ound hal o he a acks we e
associa ed wi h isk-enhancing human beha iou s. Ou o 271 well-documen ed a acks, 47.6% we e associa ed
wi h ce ain human beha iou s ha may ha e con ibu ed o he p obabili y o su e ing an a ack. Wi hin
he p incipal ca ego y (child en le una ended by hei pa en s), he main species esponsible o 91.9% o
hese a acks we e couga s (50.8%), coyo es (27.9%) and black bea s (13.2%). (The couga pic u e has been
downloaded om 123RF ROYALTY FREE STOCK PHOTOS (h p://www.123 .com), Image ID 2597979, E ic
Isselee).
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Scien i ic RepoR s | 6:20552 | DOI: 10.1038/s ep20552
and manage agg essi e encoun e s. Bu nowadays, educa ional and in e p e i e e o s aimed a dec easing he
isk o la ge ca ni o e a acks should no ocus exclusi ely on people li ing in u al and wilde ness a eas. Indeed,
many people li ing in ci ies should also be included wi hin he ca ego y o g oups a isk because o he inc easing
numbe o hem enjoying ou doo ac i i ies in a eas inhabi ed by la ge ca ni o es and he expanding popula ion
o ca ni o es (mainly coyo es) in subu ban a eas.
Al hough la ge ca ni o e a acks on humans a e in luenced by he in e ac ion be ween mul iple human- and
animal- ela ed ac o s, adap ing ou own beha iou s when coexis ing wi h la ge ca ni o es has he po en ial o
educe he numbe o a acks o abou hal o oday’s le el. The examples p o ided by he nume ous cases o chil-
d en inju ed/killed while le una ended by hei pa en s, a acks on people jogging/walking alone a wiligh and
du ing hun ing, should make us e lec on ou esponsibili ies, he possibili y o dec easing he numbe o hese
agic e en s and changing he obse ed ends. Unde s anding he ci cums ances associa ed wi h la ge ca ni o e
a acks should help us o educe hem and he eby minimize he ole ha ea and supposi ion may play in la ge
ca ni o e managemen and conse a ion.
Me hods
Collec ion o eco ds o la ge ca ni o e a acks on humans. Reco ds o la ge ca ni o e a acks (i.e.
a acks esul ing in physical inju y o dea h) on humans o he b own bea , black bea , couga , wol and coyo e
we e collec ed o No h Ame ica ( he Uni ed S a es and Canada). In addi ion, wi h he aim o b oaden ou
esea ch and ob ain a gene al pic u e o la ge ca ni o e a acks on humans in de eloped coun ies, we com-
plemen ed he No h Ame ican da ase wi h in o ma ion on b own bea a acks in h ee Eu opean coun ies
(Sweden, Finland and Spain) as well as da a on a acks by pola bea s in Eu ope (S alba d; No way), Russia, he
Uni ed S a es, and Canada. Ou ime pe iod spanned om 1955 o 2014 and ou sea ch esul ed in a o al o 697
a acks o la ge ca ni o es on people.
We conside ha we bo h eco ded he majo i y o such e en s occu ing du ing he las six decades in hese
de eloped coun ies and a oided bias due o possible changes in epo ing p obabili y gi en (i) he la ge numbe
o expe ienced people in ol ed in he wo k (some o hem had hei own da abase on a acks, which s a ed a he
beginning o he 1900s), (ii) he mul iple sou ces o in o ma ion used o collec eco ded a acks and (iii) he sen-
sa ional na u e and media impac s o a acks ha end wi h inju ies o he dea h o he ic im since he beginning
o he pas cen u y. Reco ds o a acks we e collec ed om unpublished epo s and PhD/MS heses, webpages
(las accessed in No embe 2014, bu cu en ly a ailable a he speci ic add esses lis ed by species below), books
and scien i ic a icles, as well as pe sonal da ase s om some o he co-au ho s. In addi ion, o comple e he da a
ob ained om he abo e-ci ed sou ces, we also collec ed dozens o news epo s om online newspape s. To do
his, o each species and a ea, we sea ched on an annual basis o news a icles on Google using he combina ion
o he ollowing e ms: “species name” + “a ack” and “species name” + “a ack” + “human”. Because o he use
o mul iple sou ces, se e al a acks ecu ed epea edly du ing he sea ch, bu we used in o ma ion such as da e,
locali y and sex/age o he ic ims o p e en duplica e eco ds in he da ase . Howe e , he lack o some eco ds
would s ill no esul in a bias in he gene al pa e ns we obse ed in he p esen wo k, because: (i) we ollowed
he same p ocedu e o each species and, hus, we collec ed a leas an equally biased sample o a acks pe species
and (ii) pa e ns o a acks on humans o e ime a e less sensi i e o unequally biased samples o a acks han
quan i a i e compa isons o he equency o a acks ac oss species (which is no he aim o he p esen wo k).
When possible, we eco ded he ollowing in o ma ion o each a ack: (1) species; (2) yea ; (3) mon h; (4)
coun y; (5) ime o he a ack du ing he day (which we classi ied in o h ee ca ego ies: wiligh , day, nigh ); (6)
ac i i y o he ic im (15 ca ego ies: hun ing, ishing, ield wo k, camping, hiking, jogging, skiing, biking, ho se
iding, ui /mush oom picking, pho og aphy, walking, dog walking, ac i i y nea he house/in he backya d,
playing); (7) size o pa y being a acked (simpli ied in o h ee ca ego ies: ic im alone, child – om 0 o 16 yea s
old– in a pa y o adul s, adul – > 16 yea s old – in a pa y o adul s); (8) end o he a ack, i.e. a ack esul ing in
human inju ies o dea h; and (9) scena io when he a ack occu ed, i.e. he ac o ha could ha e igge ed he
a ack. We we e able o delinea e eigh ca ego ies: emale wi h young, agg essi e eac ion a e a sudden encoun-
e (i.e. a pe son su p ises he la ge ca ni o e a close ange), ood de ence (e.g. a bea close o a ca cass), ood
condi ioning (i.e. encoun e wi h a la ge ca ni o e ha consumes human-de i ed oods, consequen ly associa ing
people wi h easily accessible, a ac i e oods, and which has los much o i s a oidance mechanisms owa ds
humans), p eda o y (i.e. when he la ge ca ni o e exploi ed a human as p ey), wounded animal (i.e. du ing hun -
ing), eeding la ge ca ni o es, and p esence o one o mo e dogs. Unleashed dogs can exace ba e he p obabili y
o a la ge ca ni o e a ack, because a dog ha uns away om a la ge ca ni o e owa ds he owne can igge a
dange ous si ua ion when he ca ni o e chases i 30. When dogs we e in ol ed, la ge ca ni o es usually ocused
hei a en ion on he dog a he han on he pe son. Howe e , in some ins ances he human was a acked as a
consequence o i s p oximi y o he dog o because o i s eac ion owa ds he la ge ca ni o e.
Below, we desc ibe he sou ces used o collec da a on la ge ca ni o e a acks on people o each species since
1955:
1. No h Ame ican b own and black bea s. We eco ded a o al o 92 and 85 a acks, espec i ely. In o ma-
ion was compiled om28, Wikipedia Lis o a al bea a acks in No h Ame ica (h p://en.wikipedia.o g/
wiki/Lis _o _ a al_bea _a acks_in_No h_Ame ica), Fa al Bea A ack S a is ics o he USA & Canada
(h p://www.blackbea hea en.com/bea -a ack-s a is ics.h m) and online newspape s. Addi ionally, we also
ex ac ed in o ma ion o he black bea om8 and Cali o nia Black Bea Public Sa e y Inciden s, Cali o nia
Depa men o Fish and Wildli e (h ps://www.wildli e.ca.go /News/Bea /Bea -Inciden s).
2. Couga . We eco ded a o al o 179 a acks. Da a on a acks we e collec ed om1,31, he Lis o Moun ain
Lion A acks (h p://www.couga in o.o g/a acks.h m), Moun ain Lion A acks om 1991 o 2000 (h p://
www.couga in o.o g/a acks2.h m), Moun ain Lion A acks om 2001 o 2010 (h p://www.couga in o.o g/

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a acks3.h m), Moun ain Lion A acks om 2011 o Now (h p://www.couga in o.o g/a acks4.h m) and on-
line newspape s.
3. Wol . We eco ded a o al o 47 a acks. Da a on a acks we e collec ed om32,33, he Wikipedia Lis o wol
a acks in No h Ame ica (h p://en.wikipedia.o g/wiki/Lis _o _wol _a acks_in_No h_Ame ica), Wikipe-
dia Lis o wol a acks (h p://en.wikipedia.o g/wiki/Lis _o _wol _a acks), Wol A acks on Humans (h p://
www.aws. cn.com/wol _a acks_on_humans.h ml) and online newspape s. We did no include he wol in
Eu ope, because p eda o y a acks on people ha e been ex emely a e du ing he las six decades, wi h he
las eco ded p eda o y a ack occu ing in 1974 in Spain32.
4. Coyo e. We eco ded a o al o 216 a acks. Da a on a acks we e collec ed om4,34–36, he Wikipedia Coyo e
a acks on humans (h p://en.wikipedia.o g/wiki/Coyo e_a acks_on_humans), Coyo e A acks on Child en
(h p://www. a min al.com/a ac.h m), Coyo e A acks: An Inc easing Subu ban P oblem (h p://eschola -
ship.o g/uc/i em/8qg662 b), Coyo e A acks On People in he U.S. and Canada (h p:// ches e .o g/sgm/lis s/
coyo e_a acks.h ml) and online newspape s.
5. Eu opean b own bea . We eco ded a o al o 65 a acks. In o ma ion om Spain was a ailable om he un-
published pe sonal da abase o J.N. and A.F.G., whe eas Fennoscandian eco ds we e ob ained om37,38 and
unpublished da a om I.K., H.N. and J.F.
6. Pola bea . We eco ded a o al o 13 a acks. In o ma ion was eco ded om Wikipedia Lis o a al bea
a acks in No h Ame ica (h p://en.wikipedia.o g/wiki/Lis _o _ a al_bea _a acks_in_No h_Ame ica) and
online newspape s (bo h No h Ame ican and Eu opean –some a acks ha e been ecen ly eco ded in he
No wegian S alba d a chipelago–).
Collec ion o eco ds on ou doo human ac i i ies. Da a on ou doo ac i i ies was only a ailable
o he US and Sweden. We collec ed he ollowing in o ma ion: (1) annual ec ea ion isi a ion in Ame ican
P o ec ed A eas published by he Na ional Pa k Se ice Visi o Use S a is ics (IRMA da a sys em), Na ional
Pa k Se ice, U.S. Depa men o he In e io , Na u al Resou ce S ewa dship and Science (h ps://i ma.nps.
go /S a s/Repo s/Na ional). To educe bias in ou analyses, we only used in o ma ion om he Na ional
Pa ks loca ed in he 30 s a es whe e a leas one la ge ca ni o e a ack occu ed since 1955 (Alaska, A izona,
Cali o nia, Colo ado, Flo ida, Geo gia, Idaho, Illinois, Kansas, Ken ucky, Massachuse s, Michigan, Minneso a,
Mon ana, New Hampshi e, New Je sey, New Mexico, New Yo k, No h Ca olina, No h Dako a, Ohio, Oklahoma,
Pennsyl ania, Tennessee, Texas, U ah, Ve mon , Vi ginia, Washing on, Wyoming); (2) s a is ics on numbe o
people doing ou doo ac i i ies in he US, which we e ob ained om39, he U.S. Depa men o he In e io , U.S.
Fish and Wildli e Se ice, and U.S. Depa men o Comme ce, U.S. Census Bu eau40–44; (3) Ame ican ends in
he spo ing goods ma ke ela ed o ou doo ac i i ies associa ed wi h a acks (c oss-coun y aining shoes,
jogging and unning shoes, camping, op ics, snow skiing, bicycles and ela ed supplies), which we e collec ed
om he U.S. Census Bu eau, S a is ical Abs ac o he Uni ed S a es45,46; and (4) S a is ics Sweden’s ime se ies
ables conce ning ou doo ac i i ies, which de i e om ULF su eys (Li ing Condi ions Su eys) om 1975
onwa ds (h p://www.scb.se/s _/Hi a-s a is ik/S a is ik-e e -amne/Le nads o hallanden/Le nads o hallanden/
Unde sokninga na-a -le nads o hallanden-ULFSILC/12202/12209/#). In o ma ion on ou doo human ac i i ies
was only used o suppo he highligh ed ends and pa e ns o la ge ca ni o e a acks; hus, i s sole unc ion is o
be suppo i e o he main ex and i was no used in ou analyses.
Collec ion o eco ds on la ge ca ni o e ha es . We used da a om b own bea , black bea , couga
and wol ha es s in ce ain US and Canadian s a es as examples o ends and numbe s in la ge ca ni o e ha es
o e ime. Fi s , b own bea ha es ing eco ds o Alaska and B i ish Columbia we e ob ained om he Alaska
Depa men o Fish and Game47,48 and M. Wolowicz unpublished da a (Big Game Ha es S a is ics 1976–2012,
B i ish Columbia), espec i ely. Second, da a on black bea ha es ing s a is ics in Alaska was ob ained om he
Alaska Depa men o Fish and Game49–51. Thi d, couga ha es ing eco ds in Colo ado, Albe a and B i ish
Columbia we e ob ained om52–54, J. Apke unpublished da a (Colo ado Di ision o Wildli e) and M. Wolowicz
unpublished da a (Big Game Ha es S a is ics 1976–2012, B i ish Columbia). Finally, wol ha es ing s a is ics
we e ex ac ed om he Alaska Depa men o Fish and Game55–58. Again, as we did o he in o ma ion on ou -
doo human ac i i ies, he eco ds on la ge ca ni o e ha es we e only used o suppo he highligh ed ends
and pa e ns o la ge ca ni o e a acks; hus, hei sole unc ion is o be suppo i e o he main ex and hey we e
no used in ou analyses.
Da a analysis. Conside ing he o al da ase on la ge ca ni o e a acks since 1955, we i s assessed whe he
he numbe o a acks a ied o e ime, on a yea ly basis, and among species by i ing a Gene alized Linea Model
(GLM) wi h he numbe o a acks agains yea and species (Ex ended Da a Table 1). We also included he in e -
ac ion e m be ween yea and species o accoun o he ac ha he numbe o a acks may a y o e ime he -
e ogeneously ac oss species. Because ou da a we e o e dispe sed, we i ed he GLM using a Nega i e Binomial
dis ibu ion ins ead o a Poisson dis ibu ion. Nex , o assess a po en ial change in he beha iou al empe amen
o la ge ca ni o es o e ime, we es ed whe he he log- ans o med age o he ic im and pa y size ( h ee le -
els) a ied o e ime and among species by i ing a linea model wi h a Gaussian dis ibu ion and a GLM wi h a
mul inomial dis ibu ion ( h ee le els), espec i ely (Ex ended Da a Tables 2 and 3). Pa y size was classi ied in o
h ee ca ego ies, which allows di e en ia ing be ween a acks on lone indi iduals and g oups, as well as i he ic-
im in a g oup was a young pe son: i) he ic im was alone; ii) he ic im was a young pe son (< 16 yea s old) in a
g oup o adul s (2 o mo e people); and iii) he ic im was an adul (> 16 yea s old) in a g oup o adul s (2 o mo e
people). We also conside ed he in e ac ion e m in hese models o accoun o he ac ha he su oga es o he
changes in he empe amen o la ge ca ni o es used may a y o e ime di e en ly ac oss species. Finally, we
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analysed a subse o he da ase conside ing only hose a acks occu ing in he US and, oge he wi h in o ma ion
on human in lux in na u al a eas, we es ed i he numbe o a acks was ela ed o he numbe o people in ol ed
in ou doo ac i i ies by building a GLM wi h a Gamma dis ibu ion, conside ing yea , he numbe o isi o s and
hei in e ac ion e m as ac o s in he model (Ex ended Da a Table 4).
Fo each analysis, we used an in o ma ion heo e ic amewo k o ank a se o compe ing models based on
AIC (Akaike’s In o ma ion C i e ion [AIC]59). We used a s epwise selec ion p ocedu e o c ea e a candida e se
o a p io i compe ing models s a ing om he simples null model (in e cep only model) o he ull model
(Ex ended Da a Tables 1, 2, 3 and 4). To selec he bes candida e model, we used AIC alue co ec ed o small
sample sizes (AICc) and Weigh ed AIC, which indica es he p obabili y ha he model selec ed is he bes among
he candida es59. Models wi hin Δ AIC < 2 we e conside ed o ha e subs an ial empi ical suppo 59. All s a is i-
cal analyses we e pe o med using R 3.0.2 s a is ical so wa e60. GLMs we e un wi h he “lme4”61 and “nlme”62
package.
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Acknowledgemen s
We hank J. Apke and M. Wolowicz o ha es s a is ics o couga s in Colo ado and b own bea s and couga s
in B i ish Columbia, espec i ely, as well as K. Logan and A. Rod igues o gene al da a on ca ni o e hun ing
and a acks. P. F edman, G. No ds öm and D. Rydbe g helped collec s a is ics on ou doo human ac i i ies
in Sweden. Ma co Fes a-Bianche , B ock Fen on and an anonymous e e ee imp o ed he i s d a o he
manusc ip . This wo k was suppo ed by he Spanish Minis y o Economy and Compe i i eness (CGL2012–
33240; FEDER co- inancing). MMD ecei ed a g an om he Kone Founda ion (#44-6977). JVLB was suppo ed
by he Spanish Minis y o Economy and Compe i i eness.
Au ho Con ibu ions
V.P., M.M.D., F.P. and J.V.L.B. ini ia ed and concei ed he s udy, V.P. p epa ed he da abase wi h he collabo a ion
o M.M.D., J.V.L.B., J.N., A.F.-G., I.K., S.H. and H.N. M.M.D. and J.V.L.B. analysed he da a, V.P. w o e he
manusc ip wi h M.M.D. and J.V.L.B. and all au ho s commen ed on he manusc ip d a .
Addi ional In o ma ion
Supplemen a y in o ma ion accompanies his pape a h p://www.na u e.com/s ep
Compe ing inancial in e es s: The au ho s decla e no compe ing inancial in e es s.
How o ci e his a icle: Pen e iani, V. e al. Human beha iou can igge la ge ca ni o e a acks in de eloped
coun ies. Sci. Rep. 6, 20552; doi: 10.1038/s ep20552 (2016).
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