BBC Focus - 03.2020

Q&A

DO ANIMALS USE MEDICINE?

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CROWDSCIENCE

There’sgrowingevidencethatanimalsare

ableto‘self-medicate’usinga varietyof

plantsandinsects.Chimpanzees,for

example,havebeenobservedswallowing

wholetheroughleavesfromAspiliaplants.

Theseleavesarebelievedtobrush

parasiticwormsfromtheirgutwall,sothat

theycanpoothewormsoutoftheirbody.

Meanwhile, more than 200 species of bird

havebeenobserved‘anting’,wherethe

birdsrubantsalongtheirfeathers,orrollin

antnests.Thiscouldbeanotherformof

parasitecontrol– thebirdsmostlyuseant

speciesthatspraytoxicformicacid.There’s

evenevidencethatAfricanelephants

self-medicate,eatinga plantfrom

theboragefamily in order to help

induce labour.

WHAT KINDS OF MEDICINE DO ANIMALS USE?

Aswitheveryevolvedtrait,it’sdownto
naturalselection.Ananimalthatcomes
acrossa newbehaviourthat’sbeneficialin
somewayis morelikelytosurviveandpass
thatbehaviourontoitsoffspring.A nice
exampleofthiscomesfrommonarch
butterflies,thecaterpillarsofwhichonlyfeed
onmilkweedplants.Monarchbutterfliesare
ofteninfectedwithdeadlyparasites,and
infectedfemalemonarchstendtolayeggs
onmilkweedspeciesthathavehigher
concentrationsofparasite-killingchemicals
called‘cardenolides’.ProfJaapdeRoodeof
EmoryUniversityinAtlanta,US,hasshown
thatthiscanreducelevelsofinfectioninthe
butterflies’caterpillars,andthatuninfected
monarchbutterfliesdon’t show the same
milkweedpreference.

HOWDOESMEDICINE

USE E VOLV E?

Mythsandfolkloreoftenciteanimalsasthe

sourceofmedicalknowledge,andtoday’s

pharmacologistsareincreasinglylookingto

self-medicatinganimalsforinspiration.The

Aspiliaplantsusedbychimpstoflushout

parasiteshavealsobeenfoundtohave

antibacterialproperties,socompounds

extractedfromtheseplantscouldhelpto

treatinfectedwounds.Orangutansin

Indonesia have been observed rubbing a

foamymixtureofsalivaandleavesfrom

anotherplant,Dracaenacantleyi, ontheir

body,andlocalindigenouspeopleusethis

plantina similarwaytorelievejointand

musclepain.Scientificanalysisofthisplant

hassinceshownthatit doesindeedhave

anti-inflammatoryproperties.Thenatural

world,it seems,is fullofhealing

compounds,andanimalscan help to point

us in the right direction.

WHAT CAN ANIMALS TEACH US ABOUT MEDICINE?

RoryGallowayis theproducerofHowdidhumansdiscover medicine?

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