The Company of Biologists

Table 1.

Measurements and predictions from the primate specimens analyzed

Sample	Observed colour	Peak reflectance (nm)	Peak spatial frequency (nm^-1)	Modal interfibre distance (nm)	Peak predicted reflectance (nm)	Prediction error (nm)	Sample size
Mandrillus sphinx
Male face (A24)	Light blue	467	0.00646	154	430	37	14
Male face (A23)	Light blue	458	0.00547	182	490	32	20
Male rump (A25)	Dark blue	378	0.00666	150	410	32	39
Male rump (A22)	Dark blue	387	0.00726	138	390	3	29
Female face (A20)	Light blue	490	0.00686	146	460	30	30
Female face (A21)	Light blue	491	0.00786	127	360	131	19
Cercopithecus aethiops sabaeus
Scrotum (A09)	Pearly blue	506	0.00428	233	760	260	6
Cercopithecus aethiops pygerythrus
Scrotum (A13)	Vivid blue	∼475^{^*}	0.00587	170	400	∼75	7

Sample	Observed colour	Peak reflectance (nm)	Peak spatial frequency (nm^-1)	Modal interfibre distance (nm)	Peak predicted reflectance (nm)	Prediction error (nm)	Sample size
Mandrillus sphinx
Male face (A24)	Light blue	467	0.00646	154	430	37	14
Male face (A23)	Light blue	458	0.00547	182	490	32	20
Male rump (A25)	Dark blue	378	0.00666	150	410	32	39
Male rump (A22)	Dark blue	387	0.00726	138	390	3	29
Female face (A20)	Light blue	490	0.00686	146	460	30	30
Female face (A21)	Light blue	491	0.00786	127	360	131	19
Cercopithecus aethiops sabaeus
Scrotum (A09)	Pearly blue	506	0.00428	233	760	260	6
Cercopithecus aethiops pygerythrus
Scrotum (A13)	Vivid blue	∼475^{^*}	0.00587	170	400	∼75	7

Reflectance data for Cercopithecus aethiops pygerythrus from Findlay (1970).