Cranial features of mainland and Commander Islands (Russia) Arctic foxes (Vulpes lagopus) reflect their diverging foraging strategies

Figures & data

Figure 1. (a) Map showing the location where the mainland (approximate coordinates 68°26'N, 171°39'E) specimens was collected (1), and the location of the two Commander Islands, (2) Bering Island (approximate coordinates 55°4'N, 166°4'E) and (3) Mednyi Island (approximate coordinates 54°40'N, 167°50'E); the copyright-free map was downloaded from www.maps-for-free.com and modified. (b) Lateral view of an Arctic fox cranium showing the three measurements taken in this study, CBL, RL and gape angle.

Table 1. ANOVA for CBL, RL, residuals of linear RL/CBL regression, and gape angle between populations: mainland (main), Mednyi Island (Med) and Bering Island (Ber). Significant values are in boldface.

Population pairs	df	CBL		RL		RL/CBL		Gape angle
		F	p	F	p	F	p	F	p
Main/Med	1	35.26	<0.0001	7.72	<0.01^a	12.23	<0.01c	52.96	<0.0001
Main/Ber	1	53.16	<0.0001	45.13	<0.0001	0.00	1.000000	20.48	<0.0001
Med/Ber	1	0.67	0.41587	7.68	<0.01b	9.89	<0.01d	4.59	0.035690

^a p = 0.006983. ^b p = 0.007170. ^c p = 0.000815. ^d p = 0.002452.

Table 2. ANOVA for CBL, RL, residuals of linear RL/CBL regression and gape angle between males (m) and females (f) in each population: mainland (main), Mednyi Island (Med) and Bering Island (Ber). Significant values are in boldface.

Populations	df	CBL		RL		RL/CBL		Gape angle
		F	p	F	p	F	p	F	p
m/f main	1	51.20	<0.0001	27.13	<0.0001	2.62	0.113193	3.01	0.090265
m/f Ber	1	34.72	<0.0001	14.98	<0.001^a	0.43	0.515839	0.31	0.580861
m/f Med	1	29.17	<0.0001	13.02	<0.01b	0.10	0.754175	0.19	0.666259

^a p = 0.000403. ^b p = 0.001188.