, -~ .

~4 G . A VERY I:T Al.

van Zyl. typing hy S. Saven and M . Schcincr. J. A. J. Ncl. M . L. Wll so n and W. J. J. " '"' R1jsscn ;tre thanked for comments on an early draft of this paper .

REFERF.N ·. Ne, ·h~trgh . Ahcrdt'

~b R. D . STONE

synchronized on a daily basis . Species with rhythms that illustrate thi> include "'""'''11111.1 .IT!nuicus (El ton . Ford. Baker & Gardner. 1931: Kikkawa. 1964: Gurnell. I

'. 9M R. 11 . STONF.

.~ tJ ., ~ .,~-~-~ -· ··-1-JH~J~~ ·-~·"¥;

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. . . !: ;' • ! (A ·"A _.if. ~ r:. ~ .

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PLAn: 11. Close up ofMHIUI of a P~rc l h.'an ~k,man ((ialenn' l'•rc 'llfltc 111)

.\}uciul orgulli:olintt

The social o rganization of the Pyrenea n desman has hccn de tailed c•l,cwhcn: (Stone. I- ~ ~ :; -,

a1ea

' • ' '. ·. . . .. ACT t Vi~·~,· I'ATTf:.RN~ -~lF TilE PYRENEAN DES~;-~ ·~

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a1ea (%) aArpeur awr1

~~~- -===-=--==-- -:.-- -----·-- ·.-.... J.' ...... ...

4'J

[' (13)

(24)

(

'l " 11 '4X' 1X 7' B June IYX .l

M2 Adull 59 119 June JYX.l ~YJunc I YX.l

Artill ;u: Jno" 11 ' ~11 " .111 711 M .1 Adul1 S\) ~7 Jun'-· 19X.l Artill : ~~o: I ~ - ~6 - · 11 ' -l~ -- :!S 7 ~ IXJulv l'IX .1 M4 Adull 112 16 June I Y~ .1 ArtilhH.· 15':?6 . 11 ' 1 ~ .. 1'1 71

IY July 19X.l MS Ju v~nile 40 02 July 19M3 Art iliac 15'21>" 10'54" ~() 71

14 July 19H.1 M 6 A dull 6'! 04 Jul y I Y~.l An iliac I Y :!t• I l Oll ' .111 70

IX July 19X.1 M 7 Adult 59 02Junc IYX-1 Boutg o.anc 15' .15 .. 10 ' 4 ~ -- .22 7X

14 June 19H4 MX A dull 62 11.1 June IYX4

14 June IYX4 Bnuiganc 15'1.1" 11 ~ -~ . ~ -' 77

MY Adult 59 07June 19X-I Uo uiganc Jn s- · ~~ ·oo · 17 X.1 ~0 June IYH -1

M 10 Adult ~X 04June IYX-1 13 June IYX4

Boutganc 15'.15" 10 '.16" 21 7Y

Mll Juvenile .15 04June IYX-1 I~ Junl' I~X~

BtlUJ~anc 15 '.15 . ,, . ,o~ I~ X-I M I~ Juvenile .17 (~ Junc 141l >~ l e was used cxc:lusivcly hy each animal. Tempo rary shelters were loc:aled in small cre vices in the hanks o f the stream anU in heaps of'rol.:k~ along its co urse: no nes ting mat eria l wa s f'ound a l t lH l 'l'

Unlike 1nos1 other members nfJhi' family. the l' yrenea n des man does no! show an y ada pt"li

' .

' .. 102

M 2

F 4 M 3

F 5

~ M 4

& F 6 t3 M 1

F 2

F

M 5

F 3

M 6

I I 12:00 16:00

sunset

'

20:00

R. 0 . STONI:

24 :00 Time (h)

sunr1se

t

04 :00 08:00 12:00

fiG . 2. The activity patterns of male: (M) and female (f) dc:srnans which w~rc: radiLHro.td.c:d un thc: Artlil;u.: a nU NCJC streams during June and July 19tD . Solid line~ indi~:.11c: the m~.· an fl'=tiPd of lll ill.:t i\ it y t 1111 11..' ,r~.·nt oil tlh.' Ill''') (Pr 1 he duration o r study.

M 7

F 7

M 8

F 8 c: M 9 "' E

' ' '

104 R . D . STONE

been well documented in studies of circadi~n rhythms (Weigent. 19f>l; Kikkawa. 1%4; Amhrose. 1973; Stebbins. 1974; Madison . 1978). but less frequentl y amongst tlws.: of short-term rhythms (Daan & Slopsema , 1978). Possible benefits which ~ccrue from such behaviour indude reduced levels of predation (Daan & Slopsema. 197!!), incre~sed cflici.:n.:y in feeding ( Lchmann. 1976). and mutual avoidance of conspecifies (Stone. 19!!6) . According to the pr.:sent data. within each part icula r stream. the onset and cessation of activity amongst neighbouring desmans was highly synchronized and the overall biphasic pattern was upheld hy all members of each population studied. Avoidance of predators is unlikely to be the key factor accounting for the observed activity patterns in desmans. si nce being active during both day and night they ar.: subjec t to a wide range of po tential preda tors. Yet. social synchroni za tion may play an integral role in reducing the level of predation. si nce the risk of an individual being killed. if active at the same time as it s conspecifics, might be less than if it w~s active independently of its conspecilics .

The mutual avoidance of neighbouring conspecilics ma y he facilitated through a sys tem of social synchronization. This may be achieved either through the regulation of activity p~ttern s, e.g. Ta/pa europaea (Stone, 1986), or movement p~ttcrn s. e.g. Tamia.1· stria/liS (Getty, 1981 ). In Galemys, the utilization of areas of range overlap by both neighbo urs Juring dilfcrcnt periods of d~ily activity (Stone. 1987) allows for their mutu~l avoidance. This. in turn. reduces the likelihood of aggressive encounters as neighbouring animals rarel y corn.: into direct contact. Indirect communic~tion is, however. possible via the regular deposition of sct•nt marks along the boundaries of individual territories (Stone. 19g6).

A fin~ I advantage of social synchronization may relate to diet and to being active at a time wh.:n prey availability is at its highest. This ha s often been shown to ht: the case . For example. some species. such as Apndemu.v sylratinH and Peromyscll.\' lllistrcllus pipistrel/u.1·) arc closely correlated with this diel abundance of aeri~l prey. At a certain . critical time when insect activity is reduced, bats cease to feed and await the secondary surge of insec ts in the prc-dawn period. In the present study. the temporal abundance of prey was renected by the foraging and feeding behaviour of desmans. which was always concentrated within this period of darkness . Unfortunately. it was not possible to determine whether the feeding success of individuals varied

At'TtVI"t Y I'AT't l'RNS O l ' l ttt ' I'YRI'Nl'AN DESMAN 111 .'1

according to the temporal availability or prey. Desmans, alt hough uctivc for 11 shorter pcnod during daylight. were rarely observed feeding during this time.

The existen

A-ihhy. K . R. ( IY 721 . Path:rns ~~r J a•l y ;.u.:ti vit y in nwmm;ds. Mamm . Rcr . 1: 171 IX5 . lh:rn~\1..'11\. I. S. ( 1'1 721 . Daily ou:ttvlly t.:ydc:-. anJ \lol'allh.:r tntl m:nt.:c~ 1111 a pt~l :tilnlllll~cy grnup. rohllf' l' /11 1111"1 IK: .WO .t I ~ Brown. T . N . ( I~K .\) . /Jrou '/1 ·.,. wwlic ·ol almcmm·. Brown , T . N . (EU .). Glasgow: Brown. Snn & Fergu.,.on Ltd . Brnwn . T . N . ( l tJX4) . Brmm \ wwlinil alnumc11 ·. Brown . T . N . (f.d .). Gli1s~ow : Brnwn. Stlll & Fer~usnn Ltd CalhtlUil . J. B. ( 1945). Die I activity rhythms of the rodt:nls MicroiiH orhrt'J!.''·"'''' ;111d St):moclon hi.,pidw lmp11lu.' . 1-."ndoJ.: r

26: 25t 27 .1. Cro v.. ~rort . W . P. (IY~4) . The ll:.tily l·yde ofaclivi ty in Hritish shrl'WS . /'nw . :=ool . .\'oc. l .oud. 12J: 71~ 7 ~9 . r>aan. S. & Slopscma, S. (I Q7X). Short · ll'l'lll rh ylhms in f

.,

1116 R 11 SlONE

GuJfrc:~ . G . K . ( 1955) . A ticiU !i tudy of thl.' a..:! I \ 11 y pf the moll· ( (alpa ntrnl'o, ·u) /:', ol"c' .\h; h 7X 6K~ Grodl insk y, W. ( 1 '16~) . ScaSllllal changc:s in the c m.:;,~t..ll a n ;.u.: lt \. it y of ''nail rod~.· nl\ 1-.'n•/ /1o/. t /J) 9: .\ 17. Gurncll. J . (I ~75) . Notes llO the ;u.:ti vity nf wild Wo~H.I mi..: c. At'"'/,·mu' ,r/1'111/t U\, 111 andi ..: t.d ..: ndn..;url.' ..; J 7.oo/ . l .m1d

17~ : ~19 ~29 .

K ;l\ ;t !l41ll. .f . I. ( 1969). lnnu ~.·IH.'I.''i ~~r li)!hl tlll ih : ll\11) nr 'lll.dl ll\.111\ll l. tl, / .t "'"C' ~11 : qx tf'"donn, 'fl''' rahdt.\) and l"n:'n''

(/) . mtru!nidt•.r} kangarOll ra ts . A mm . lldwr . 22: ~h~ ::!7l Madison . D . ( \97H) . Mnvl'ml'nt llllill"iltor:-. o f rl.' proUUI."II \t' 1.'\CI\I.' alllP ilg l"t' lll .dt• tl lt'ad~m ,,,If..•, "' n .. '\'t';t lcd h)

radiotelemetry . J . . \lammed. ~Y : 10~ X·O Marten . (i . G . t II.J7.l) . 1 ime p:lltcrn ... ~~r Pn•lllll '' " ' il~ll \il~ ,ln, l tllnr t''" '':l ;r\rHII \\rill 1\t'.i\ lr •• : r .I .\ lom111!1l ~: 1(,'} lXX Miller. R. S. (I Y55). A~:t iv ity rh yth m~ in thl' \\\111J Jlll.lll:-ot' 1.-lt'""' 'lllll\ "lt 0111 11 1 J .tnJ 1 ht· ILtnL \oh: t ( 'll·thrtot/oHn'

xlan•tdll.t) . fro, ·. ::.m d . . \ "oc /.mu/ 12~ : ~()~ 51 1.1 . Nkull. M . E. (I 'IX:!). Rt•prodllf tin· ,·,-,doKy of Tt'nru t•t·uuJutu' I /111t '1 f11'11ro J'o,·,·, tdw ·J 111 1/t, · ."i1 ·1 1 /w//1·1 ll 11ruhl Ph i)

thesis. Uni\'crsit)' of A~rtkt'll . Ni~th ;tmmcr . U . (II.J70). Bco h;u:h tungen am P}rc n l.';t n · lk~man . (:o/1'111 n f'IH ' • I