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er¡¡become¡¡curiously¡¡blended¡¡together£»¡¡and¡¡for¡¡a¡¡long¡¡period¡¡exhibit¡¡traces¡¡of¡¡the¡¡instincts¡¡of¡¡either¡¡parent£º¡¡for¡¡example£»¡¡Le¡¡Roy¡¡describes¡¡a¡¡dog£»¡¡whose¡¡great¡­grandfather¡¡was¡¡a¡¡wolf£»¡¡and¡¡this¡¡dog¡¡showed¡¡a¡¡trace¡¡of¡¡its¡¡wild¡¡parentage¡¡only¡¡in¡¡one¡¡way£»¡¡by¡¡not¡¡coming¡¡in¡¡a¡¡straight¡¡line¡¡to¡¡his¡¡master¡¡when¡¡called¡£¡¡
Domestic¡¡instincts¡¡are¡¡sometimes¡¡spoken¡¡of¡¡as¡¡actions¡¡which¡¡have¡¡become¡¡inherited¡¡solely¡¡from¡¡long¡­continued¡¡and¡¡compulsory¡¡habit£»¡¡but¡¡this£»¡¡I¡¡think£»¡¡is¡¡not¡¡true¡£¡¡No¡¡one¡¡would¡¡ever¡¡have¡¡thought¡¡of¡¡teaching£»¡¡or¡¡probably¡¡could¡¡have¡¡taught£»¡¡the¡¡tumbler¡­pigeon¡¡to¡¡tumble£»¡¡an¡¡action¡¡which£»¡¡as¡¡I¡¡have¡¡witnessed£»¡¡is¡¡performed¡¡by¡¡young¡¡birds£»¡¡that¡¡have¡¡never¡¡seen¡¡a¡¡pigeon¡¡tumble¡£¡¡We¡¡may¡¡believe¡¡that¡¡some¡¡one¡¡pigeon¡¡showed¡¡a¡¡slight¡¡tendency¡¡to¡¡this¡¡strange¡¡habit£»¡¡and¡¡that¡¡the¡¡long¡­continued¡¡selection¡¡of¡¡the¡¡best¡¡individuals¡¡in¡¡successive¡¡generations¡¡made¡¡tumblers¡¡what¡¡they¡¡now¡¡are£»¡¡and¡¡near¡¡Glasgow¡¡there¡¡are¡¡house¡­tumblers£»¡¡as¡¡I¡¡hear¡¡from¡¡Mr¡¡Brent£»¡¡which¡¡cannot¡¡fly¡¡eighteen¡¡inches¡¡high¡¡without¡¡going¡¡head¡¡over¡¡heels¡£¡¡It¡¡may¡¡be¡¡doubted¡¡whether¡¡any¡¡one¡¡would¡¡have¡¡thought¡¡of¡¡training¡¡a¡¡dog¡¡to¡¡point£»¡¡had¡¡not¡¡some¡¡one¡¡dog¡¡naturally¡¡shown¡¡a¡¡tendency¡¡in¡¡this¡¡line£»¡¡and¡¡this¡¡is¡¡known¡¡occasionally¡¡to¡¡happen£»¡¡as¡¡I¡¡once¡¡saw¡¡in¡¡a¡¡pure¡¡terrier¡£¡¡When¡¡the¡¡first¡¡tendency¡¡was¡¡once¡¡displayed£»¡¡methodical¡¡selection¡¡and¡¡the¡¡inherited¡¡effects¡¡of¡¡compulsory¡¡training¡¡in¡¡each¡¡successive¡¡generation¡¡would¡¡soon¡¡complete¡¡the¡¡work£»¡¡and¡¡unconscious¡¡selection¡¡is¡¡still¡¡at¡¡work£»¡¡as¡¡each¡¡man¡¡tries¡¡to¡¡procure£»¡¡without¡¡intending¡¡to¡¡improve¡¡the¡¡breed£»¡¡dogs¡¡which¡¡will¡¡stand¡¡and¡¡hunt¡¡best¡£¡¡On¡¡the¡¡other¡¡hand£»¡¡habit¡¡alone¡¡in¡¡some¡¡cases¡¡has¡¡sufficed£»¡¡no¡¡animal¡¡is¡¡more¡¡difficult¡¡to¡¡tame¡¡than¡¡the¡¡young¡¡of¡¡the¡¡wild¡¡rabbit£»¡¡scarcely¡¡any¡¡animal¡¡is¡¡tamer¡¡than¡¡the¡¡young¡¡of¡¡the¡¡tame¡¡rabbit£»¡¡but¡¡I¡¡do¡¡not¡¡suppose¡¡that¡¡domestic¡¡rabbits¡¡have¡¡ever¡¡been¡¡selected¡¡for¡¡tameness£»¡¡and¡¡I¡¡presume¡¡that¡¡we¡¡must¡¡attribute¡¡the¡¡whole¡¡of¡¡the¡¡inherited¡¡change¡¡from¡¡extreme¡¡wildness¡¡to¡¡extreme¡¡tameness£»¡¡simply¡¡to¡¡habit¡¡and¡¡long¡­continued¡¡close¡¡confinement¡£¡¡
Natural¡¡instincts¡¡are¡¡lost¡¡under¡¡domestication£º¡¡a¡¡remarkable¡¡instance¡¡of¡¡this¡¡is¡¡seen¡¡in¡¡those¡¡breeds¡¡of¡¡fowls¡¡which¡¡very¡¡rarely¡¡or¡¡never¡¡become¡¡'broody£»'¡¡that¡¡is£»¡¡never¡¡wish¡¡to¡¡sit¡¡on¡¡their¡¡eggs¡£¡¡Familiarity¡¡alone¡¡prevents¡¡our¡¡seeing¡¡how¡¡universally¡¡and¡¡largely¡¡the¡¡minds¡¡of¡¡our¡¡domestic¡¡animals¡¡have¡¡been¡¡modified¡¡by¡¡domestication¡£¡¡It¡¡is¡¡scarcely¡¡possible¡¡to¡¡doubt¡¡that¡¡the¡¡love¡¡of¡¡man¡¡has¡¡become¡¡instinctive¡¡in¡¡the¡¡dog¡£¡¡All¡¡wolves£»¡¡foxes£»¡¡jackals£»¡¡and¡¡species¡¡of¡¡the¡¡cat¡¡genus£»¡¡when¡¡kept¡¡tame£»¡¡are¡¡most¡¡eager¡¡to¡¡attack¡¡poultry£»¡¡sheep£»¡¡and¡¡pigs£»¡¡and¡¡this¡¡tendency¡¡has¡¡been¡¡found¡¡incurable¡¡in¡¡dogs¡¡which¡¡have¡¡been¡¡brought¡¡home¡¡as¡¡puppies¡¡from¡¡countries£»¡¡such¡¡as¡¡Tierra¡¡del¡¡Fuego¡¡and¡¡Australia£»¡¡where¡¡the¡¡savages¡¡do¡¡not¡¡keep¡¡these¡¡domestic¡¡animals¡£¡¡How¡¡rarely£»¡¡on¡¡the¡¡other¡¡hand£»¡¡do¡¡our¡¡civilised¡¡dogs£»¡¡even¡¡when¡¡quite¡¡young£»¡¡require¡¡to¡¡be¡¡taught¡¡not¡¡to¡¡attack¡¡poultry£»¡¡sheep£»¡¡and¡¡pigs£¡¡¡No¡¡doubt¡¡they¡¡occasionally¡¡do¡¡make¡¡an¡¡attack£»¡¡and¡¡are¡¡then¡¡beaten£»¡¡and¡¡if¡¡not¡¡cured£»¡¡they¡¡are¡¡destroyed£»¡¡so¡¡that¡¡habit£»¡¡with¡¡some¡¡degree¡¡of¡¡selection£»¡¡has¡¡probably¡¡concurred¡¡in¡¡civilising¡¡by¡¡inheritance¡¡our¡¡dogs¡£¡¡On¡¡the¡¡other¡¡hand£»¡¡young¡¡chickens¡¡have¡¡lost£»¡¡wholly¡¡by¡¡habit£»¡¡that¡¡fear¡¡of¡¡the¡¡dog¡¡and¡¡cat¡¡which¡¡no¡¡doubt¡¡was¡¡originally¡¡instinctive¡¡in¡¡them£»¡¡in¡¡the¡¡same¡¡way¡¡as¡¡it¡¡is¡¡so¡¡plainly¡¡instinctive¡¡in¡¡young¡¡pheasants£»¡¡though¡¡reared¡¡under¡¡a¡¡hen¡£¡¡It¡¡is¡¡not¡¡that¡¡chickens¡¡have¡¡lost¡¡all¡¡fear£»¡¡but¡¡fear¡¡only¡¡of¡¡dogs¡¡and¡¡cats£»¡¡for¡¡if¡¡the¡¡hen¡¡gives¡¡the¡¡danger¡­chuckle£»¡¡they¡¡will¡¡run¡¡£¨more¡¡especially¡¡young¡¡turkeys£©¡¡from¡¡under¡¡her£»¡¡and¡¡conceal¡¡themselves¡¡in¡¡the¡¡surrounding¡¡grass¡¡or¡¡thickets£»¡¡and¡¡this¡¡is¡¡evidently¡¡done¡¡for¡¡the¡¡instinctive¡¡purpose¡¡of¡¡allowing£»¡¡as¡¡we¡¡see¡¡in¡¡wild¡¡ground¡­birds£»¡¡their¡¡mother¡¡to¡¡fly¡¡away¡£¡¡But¡¡this¡¡instinct¡¡retained¡¡by¡¡our¡¡chickens¡¡has¡¡become¡¡useless¡¡under¡¡domestication£»¡¡for¡¡the¡¡mother¡­hen¡¡has¡¡almost¡¡lost¡¡by¡¡disuse¡¡the¡¡power¡¡of¡¡flight¡£¡¡
Hence£»¡¡we¡¡may¡¡conclude£»¡¡that¡¡domestic¡¡instincts¡¡have¡¡been¡¡acquired¡¡and¡¡natural¡¡instincts¡¡have¡¡been¡¡lost¡¡partly¡¡by¡¡habit£»¡¡and¡¡partly¡¡by¡¡man¡¡selecting¡¡and¡¡accumulating¡¡during¡¡successive¡¡generations£»¡¡peculiar¡¡mental¡¡habits¡¡and¡¡actions£»¡¡which¡¡at¡¡first¡¡appeared¡¡from¡¡what¡¡we¡¡must¡¡in¡¡our¡¡ignorance¡¡call¡¡an¡¡accident¡£¡¡In¡¡some¡¡cases¡¡compulsory¡¡habit¡¡alone¡¡has¡¡sufficed¡¡to¡¡produce¡¡such¡¡inherited¡¡mental¡¡changes£»¡¡in¡¡other¡¡cases¡¡compulsory¡¡habit¡¡has¡¡done¡¡nothing£»¡¡and¡¡all¡¡has¡¡been¡¡the¡¡result¡¡of¡¡selection£»¡¡pursued¡¡both¡¡methodically¡¡and¡¡unconsciously£»¡¡but¡¡in¡¡most¡¡cases£»¡¡probably£»¡¡habit¡¡and¡¡selection¡¡have¡¡acted¡¡together¡£¡¡
We¡¡shall£»¡¡perhaps£»¡¡best¡¡understand¡¡how¡¡instincts¡¡in¡¡a¡¡state¡¡of¡¡nature¡¡have¡¡become¡¡modified¡¡by¡¡selection£»¡¡by¡¡considering¡¡a¡¡few¡¡cases¡£¡¡I¡¡will¡¡select¡¡only¡¡three£»¡¡out¡¡of¡¡the¡¡several¡¡which¡¡I¡¡shall¡¡have¡¡to¡¡discuss¡¡in¡¡my¡¡future¡¡work£»¡¡namely£»¡¡the¡¡instinct¡¡which¡¡leads¡¡the¡¡cuckoo¡¡to¡¡lay¡¡her¡¡eggs¡¡in¡¡other¡¡birds'¡¡nests£»¡¡the¡¡slave¡­making¡¡instinct¡¡of¡¡certain¡¡ants£»¡¡and¡¡the¡¡comb¡­making¡¡power¡¡of¡¡the¡¡hive¡­bee£º¡¡these¡¡two¡¡latter¡¡instincts¡¡have¡¡generally£»¡¡and¡¡most¡¡justly£»¡¡been¡¡ranked¡¡by¡¡naturalists¡¡as¡¡the¡¡most¡¡wonderful¡¡of¡¡all¡¡known¡¡instincts¡£¡¡
It¡¡is¡¡now¡¡commonly¡¡admitted¡¡that¡¡the¡¡more¡¡immediate¡¡and¡¡final¡¡cause¡¡of¡¡the¡¡cuckoo's¡¡instinct¡¡is£»¡¡that¡¡she¡¡lays¡¡her¡¡eggs£»¡¡not¡¡daily£»¡¡but¡¡at¡¡intervals¡¡of¡¡two¡¡or¡¡three¡¡days£»¡¡so¡¡that£»¡¡if¡¡she¡¡were¡¡to¡¡make¡¡her¡¡own¡¡nest¡¡and¡¡sit¡¡on¡¡her¡¡own¡¡eggs£»¡¡those¡¡first¡¡laid¡¡would¡¡have¡¡to¡¡be¡¡left¡¡for¡¡some¡¡time¡¡unincubated£»¡¡or¡¡there¡¡would¡¡be¡¡eggs¡¡and¡¡young¡¡birds¡¡of¡¡different¡¡ages¡¡in¡¡the¡¡same¡¡nest¡£¡¡If¡¡this¡¡were¡¡the¡¡case£»¡¡the¡¡process¡¡of¡¡laying¡¡and¡¡hatching¡¡might¡¡be¡¡inconveniently¡¡long£»¡¡more¡¡especially¡¡as¡¡she¡¡has¡¡to¡¡migrate¡¡at¡¡a¡¡very¡¡early¡¡period£»¡¡and¡¡the¡¡first¡¡hatched¡¡young¡¡would¡¡probably¡¡have¡¡to¡¡be¡¡fed¡¡by¡¡the¡¡male¡¡alone¡£¡¡But¡¡the¡¡American¡¡cuckoo¡¡is¡¡in¡¡this¡¡predicament£»¡¡for¡¡she¡¡makes¡¡her¡¡own¡¡nest¡¡and¡¡has¡¡eggs¡¡and¡¡young¡¡successively¡¡hatched£»¡¡all¡¡at¡¡the¡¡same¡¡time¡£¡¡It¡¡has¡¡been¡¡asserted¡¡that¡¡the¡¡American¡¡cuckoo¡¡occasionally¡¡lays¡¡her¡¡eggs¡¡in¡¡other¡¡birds'¡¡nests£»¡¡but¡¡I¡¡hear¡¡on¡¡the¡¡high¡¡authority¡¡of¡¡Dr¡£¡¡Brewer£»¡¡that¡¡this¡¡is¡¡a¡¡mistake¡£¡¡Nevertheless£»¡¡I¡¡could¡¡give¡¡several¡¡instances¡¡of¡¡various¡¡birds¡¡which¡¡have¡¡been¡¡known¡¡occasionally¡¡to¡¡lay¡¡their¡¡eggs¡¡in¡¡other¡¡birds'¡¡nests¡£¡¡Now¡¡let¡¡us¡¡suppose¡¡that¡¡the¡¡ancient¡¡progenitor¡¡of¡¡our¡¡European¡¡cuckoo¡¡had¡¡the¡¡habits¡¡of¡¡the¡¡American¡¡cuckoo£»¡¡but¡¡that¡¡occasionally¡¡she¡¡laid¡¡an¡¡egg¡¡in¡¡another¡¡bird's¡¡nest¡£¡¡If¡¡the¡¡old¡¡bird¡¡profited¡¡by¡¡this¡¡occasional¡¡habit£»¡¡or¡¡if¡¡the¡¡young¡¡were¡¡made¡¡more¡¡vigorous¡¡by¡¡advantage¡¡having¡¡been¡¡taken¡¡of¡¡the¡¡mistaken¡¡maternal¡¡instinct¡¡of¡¡another¡¡bird£»¡¡than¡¡by¡¡their¡¡own¡¡mother's¡¡care£»¡¡encumbered¡¡as¡¡she¡¡can¡¡hardly¡¡fail¡¡to¡¡be¡¡by¡¡having¡¡eggs¡¡and¡¡young¡¡of¡¡different¡¡ages¡¡at¡¡the¡¡same¡¡time£»¡¡then¡¡the¡¡old¡¡birds¡¡or¡¡the¡¡fostered¡¡young¡¡would¡¡gain¡¡an¡¡advantage¡£¡¡And¡¡analogy¡¡would¡¡lead¡¡me¡¡to¡¡believe£»¡¡that¡¡the¡¡young¡¡thus¡¡reared¡¡would¡¡be¡¡apt¡¡to¡¡follow¡¡by¡¡inheritance¡¡the¡¡occasional¡¡and¡¡aberrant¡¡habit¡¡of¡¡their¡¡mother£»¡¡and¡¡in¡¡their¡¡turn¡¡would¡¡be¡¡apt¡¡to¡¡lay¡¡their¡¡eggs¡¡in¡¡other¡¡birds'¡¡nests£»¡¡and¡¡thus¡¡be¡¡successful¡¡in¡¡rearing¡¡their¡¡young¡£¡¡By¡¡a¡¡continued¡¡process¡¡of¡¡this¡¡nature£»¡¡I¡¡believe¡¡that¡¡the¡¡strange¡¡instinct¡¡of¡¡our¡¡cuckoo¡¡could¡¡be£»¡¡and¡¡has¡¡been£»¡¡generated¡£¡¡I¡¡may¡¡add¡¡that£»¡¡according¡¡to¡¡Dr¡£¡¡Gray¡¡and¡¡to¡¡some¡¡other¡¡observers£»¡¡the¡¡European¡¡cuckoo¡¡has¡¡not¡¡utterly¡¡lost¡¡all¡¡maternal¡¡love¡¡and¡¡care¡¡for¡¡her¡¡own¡¡offspring¡£¡¡
The¡¡occasional¡¡habit¡¡of¡¡birds¡¡laying¡¡their¡¡eggs¡¡in¡¡other¡¡birds'¡¡nests£»¡¡either¡¡of¡¡the¡¡same¡¡or¡¡of¡¡a¡¡distinct¡¡species£»¡¡is¡¡not¡¡very¡¡uncommon¡¡with¡¡the¡¡Gallinaceae£»¡¡and¡¡this¡¡perhaps¡¡explains¡¡the¡¡origin¡¡of¡¡a¡¡singular¡¡instinct¡¡in¡¡the¡¡allied¡¡group¡¡of¡¡ostriches¡£¡¡For¡¡several¡¡hen¡¡ostriches£»¡¡at¡¡least¡¡in¡¡the¡¡case¡¡of¡¡the¡¡American¡¡species£»¡¡unite¡¡and¡¡lay¡¡first¡¡a¡¡few¡¡eggs¡¡in¡¡one¡¡nest¡¡and¡¡then¡¡in¡¡another£»¡¡and¡¡these¡¡are¡¡hatched¡¡by¡¡the¡¡males¡£¡¡This¡¡instinct¡¡may¡¡probably¡¡be¡¡accounted¡¡for¡¡by¡¡the¡¡fact¡¡of¡¡the¡¡hens¡¡laying¡¡a¡¡large¡¡number¡¡of¡¡eggs£»¡¡but£»¡¡as¡¡in¡¡the¡¡case¡¡of¡¡the¡¡cuckoo£»¡¡at¡¡intervals¡¡of¡¡two¡¡or¡¡three¡¡days¡£¡¡This¡¡instinct£»¡¡however£»¡¡of¡¡the¡¡American¡¡ostrich¡¡has¡¡not¡¡as¡¡yet¡¡been¡¡perfected£»¡¡for¡¡a¡¡surprising¡¡number¡¡of¡¡eggs¡¡lie¡¡strewed¡¡over¡¡the¡¡plains£»¡¡so¡¡that¡¡in¡¡one¡¡day's¡¡hunting¡¡I¡¡picked¡¡up¡¡no¡¡less¡¡than¡¡twenty¡¡lost¡¡and¡¡wasted¡¡eggs¡£¡¡
Many¡¡bees¡¡are¡¡parasitic£»¡¡and¡¡always¡¡lay¡¡their¡¡eggs¡¡in¡¡the¡¡nests¡¡of¡¡bees¡¡of¡¡other¡¡kinds¡£¡¡This¡¡case¡¡is¡¡more¡¡remarkable¡¡than¡¡that¡¡of¡¡the¡¡cuckoo£»¡¡for¡¡these¡¡bees¡¡have¡¡not¡¡only¡¡their¡¡instincts¡¡but¡¡their¡¡structure¡¡modified¡¡in¡¡accordance¡¡with¡¡their¡¡parasitic¡¡habits£»¡¡for¡¡they¡¡do¡¡not¡¡possess¡¡the¡¡pollen¡­collecting¡¡apparatus¡¡which¡¡would¡¡be¡¡necessary¡¡if¡¡they¡¡had¡¡to¡¡store¡¡food¡¡for¡¡their¡¡own¡¡young¡£¡¡Some¡¡species£»¡¡likewise£»¡¡of¡¡Sphegidae¡¡£¨wasp¡­like¡¡insects£©¡¡are¡¡parasitic¡¡on¡¡other¡¡species£»¡¡and¡¡M¡£¡¡Fabre¡¡has¡¡lately¡¡shown¡¡good¡¡reason¡¡for¡¡believing¡¡that¡¡although¡¡the¡¡Tachytes¡¡nigra¡¡generally¡¡makes¡¡its¡¡own¡¡burrow¡¡and¡¡stores¡¡it¡¡with¡¡paralysed¡¡prey¡¡for¡¡its¡¡own¡¡larvae¡¡to¡¡feed¡¡on£»¡¡yet¡¡that¡¡when¡¡this¡¡insect¡¡finds¡¡a¡¡burrow¡¡already¡¡made¡¡and¡¡stored¡¡by¡¡another¡¡sphex£»¡¡it¡¡takes¡¡advantage¡¡of¡¡the¡¡prize£»¡¡and¡¡becomes¡¡for¡¡the¡¡occasion¡¡parasitic¡£¡¡In¡¡this¡¡case£»¡¡as¡¡with¡¡the¡¡supposed¡¡case¡¡of¡¡the¡¡cuckoo£»¡¡I¡¡can¡¡see¡¡no¡¡difficulty¡¡in¡¡natural¡¡selection¡¡making¡¡an¡¡occasional¡¡habit¡¡permanent£»¡¡if¡¡of¡¡advantage¡¡to¡¡the¡¡species£»¡¡and¡¡if¡¡the¡¡insect¡¡whose¡¡nest¡¡and¡¡stored¡¡food¡¡are¡¡thus¡¡feloniously¡¡appropriated£»¡¡be¡¡not¡¡thus¡¡exterminated¡£¡¡
Slave¡­making¡¡instinct¡£¡¡This¡¡remarkable¡¡instinct¡¡was¡¡first¡¡discovered¡¡in¡¡the¡¡Formica¡¡£¨Polyerges£©¡¡rufescens¡¡by¡¡Pierre¡¡Huber£»¡¡a¡¡better¡¡observer¡¡even¡¡than¡¡his¡¡celebrated¡¡father¡£¡¡This¡¡ant¡¡is¡¡absolutely¡¡dependent¡¡on¡¡its¡¡slaves£»¡¡without¡¡their

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