Table 2.

Summary of conclusions reached in the text.

categories
taxon	principal function of white and black pelagea	likelihoodb
(a) black and white quills
echidnas	aposematism	likely
tenrecsc	aposematism	likely
hedgehogs	aposematism	likely
new world porcupines	aposematism	very likely
old world porcupines	aposematism	very likely
(b) horizontal white dorsal fur
mephitids, mustelidsc, herpestidsc	aposematism	very likely
striped possumsc	aposematism	likely
anteatersc	aposematism	possible
(c) black and white face masks
canidsc, procyonidsc, mustelids, mephitids, viverridsc	aposematism	likely
possumsc, dwarf lemursc and three-toed sloths	anti-glare	best guess
lemursc	conspec signals	best guess
callitrichidsc	sexual signals	best guess
guenonsc	—	unknown
old world monkeysc, gibbons	—	unknown
artiodactylsc	conspec signals	possible
	or thermoregulation	best guess
(d) contrasting necks or chests
gymnuresc, mustelidsc, viverridsc	aposematism	likely
various species (e.g. Ryukyu flying fox)	—	unknown
ursidsc	dominance badges	best guess
(e) body with blocks of black and white fur
various solitary species (e.g. Malayan tapir)	disruptive	best guess
various social species (e.g. b&w colobus, gazelles)	conspec signals	best guessd
various species with horizontal border (e.g. blackbuck)	—	unknown
(f) black body and white spots or blotches
various species (e.g. quolls)	pattern blending	likely
(g) trunk with black transverse stripes
marsupialsc, carnivoresc, duikersc	pattern blending	best guess
zebras	—	unknown
(h) contrasting feet, legs and rumps
feet: kangaroosc, primatesc	non-functional	best guess
legs: carnivoresc	aposematism	best guess
legs: bovidsc	conspec signals	possible
rumps: artiodactylsc	signalse or thermorgn	possible
(i) black and white tails
ringed tails: primatesc carnivoresc	conspec signals	likely
ringed tails: carnivoresc	aposematism	best guess
white tails: carnivoresc	aposematism	likely
white tail tips: many species (e.g. elephant shrew)	luresf	possible
black tail tips: many species (e.g. springhare)	conspec signals	best guess
(j) all white
carnivoresc	background matching or	likelyg
	thermoregulation	possible
artiodactylsc	background matching or	likelyg
	thermoregulation	possible
marsupialsc, sifakasc	—	unknown
(k) sexual dichromatismh
pelage: lemursc, gibbonsc	intrasexual competition	possible
ornaments: various species (e.g. lion)	inter/intrasexual competition	possible
genitalia: baboonsc, managabeysc, macaquesc	intrasexual competition	possible

^aRefers to function most likely to influence fitness but other functional consequences may apply.

^bVery likely: no alternative hypothesis can explain distribution of the coloration across species but still not tested systematically. Likely: best hypothesis but others cannot be dismissed. Possible: based on indirect supporting evidence only. Best guess: alternative hypotheses could apply and no systematic tests carried out. Unknown: no hypothesis stands up to scrutiny.

^cOnly some species in the family exhibit the coloration.

^dBest guess for colobus, but gazelles: possible.

^eSignalling to predators or conspecifics.

^fCarnivores.

^gParticularly arctic species.

^hSee electronic supplementary material.