Dog hair do not have the same length for the whole year, since they are changing constantly during the year. The summer coat is shorter and thinner, the winter coat longer and thicker. But also in the middle-time are the individual hair changing. In every case, the dog has, except of hairless, the most thick coat dorsally (at the top of back), where it saves the animal against the bad weather, while the ventral (belly) parts of body is the coat less thick. The dog hair are growing from nests (dermatoms). The individual nest creates a skin fold, which from grow groups of hair, and they vary in length and thickness. It is meant - one thick medullar hair, a few thinner medullar hairs both dark and light. Also a few thin medullar dark or light hairs and a few thin light hairs without medulla. At dogs kept outside are the nests united to groups of three (triads), at dogs kept inside are the nests individual. At the belly area are the nests individual at all breeds. The hair on dorsal parts of body are longer, thinner and darker. On ventral area grow (up to exceptions) hair shorter and lighter.

number of nests on cm2	number of hair in one nest	number of hair on 1cm2	the occurrence of individual types of hair in the nest length mm/thickness mm number of hair in nest
			type 1	type 2	type 3	type 4	type 5	type 6
Czechoslovakian wolfdog - September 1997
432 (triads)	31 - 37	13392 -15984	33-35 / 0,1305 1	33 / 0,1215 2-3	25-30 / 0,06-0,09 3-4		25 / 0,04-0,054 9	20 / 0,03 20-37
German Shepherd - July 1997
168 (triads)	6 - 20	1008 - 3360	40-50 / 0,12-0,14 1	20-30 / 0,07-0,1 3-4		20-25 / 0,03-0,04 8		20 / 0,02 16
New-foundland - October 1997
210 (triads)	6 - 8	1260 - 1680	90 / 0,058 1	130 / 0,085 3	60-70 / 0,054 6	30-40 / 0,027-0,036 11-17		30 / 0,02 rare
Briard - November 1997
240-270 (triads)	5	1215 - 1350	the ratio of individual kinds of hair wasn´t mentioned
Poodle - large white - December 1997
330-390 (triads)	4 - 5	1650 - 1980	80 / 0,07 1	75 / 0,054-0,06 8	70 / 0,027-0,036 18	70 / 0,018-0,054 18		40 / 0,013 5
Red fox - August 1997
1350 (triads)	8	10800	45-50 / 0,085 1	20 / 0,1 2	35 / 0,047 16	15 / 0,012-0,02 40		-
Siberian husky - November 1997
216 (triads)	8 - 10	1728 - 2160	55 / 0,12 1	45 / 0,09 3	35 / 0,06 3	40 / 0,005-0,022 5		-
Alaskan malamute - January 1998
162 (triads)	7 - 8	800 - 1139	25-30 / 0,1-0,108 1	25-30 / 0,08 2	25-30 / 0,045 1	25-30 / 0,026-0,036 8	25-30 / 0,03 1	-
Irish setter - November 1997
240 (triads)	7	2310	80-100 / 0,07 1	40 / 0,09 40	18-20 / 0,054-0,09 50		16-18 / 0,04 140	-
Foxhound shorthair (hybrid) - January 1998
162 (triads)	7 - 8	800 - 1139	15-20 / 0,12 1	15-20 / 0,06 2	15-20 / 0,04 1	15-20 / 0,03 4	15-20 / 0,01-0,02 3	-
American Staffordshire terrier - October 1997
240	12 - 15	2800 - 3600	13 / 0,126 1	9-10 /0,07- 0,1 3		7-11 / 0,03 8	6-8 / 0,013-0,027 2	-
Yorkshire terrier - December 1997
780-810 (triads)	3	2160 - 2430	180 / 0,08-0,13 1	140 / 0,05-0,06 9	90-140 / 0,02-0,04 15	50-90 / 0,02-0,04 7	50 / 0,03 1	-
Japan chin (3 month old) - November 1997
560-651	6	3300 - 3900	25-50 / 0,03-0,06 1	30-35 / 0,01-0,02 4		20-45 / 0,009-0,01 6	-	-
Doberman - November 1997
297-510 (triads)	3 - 4	891 - 1530	the ratio of individual kinds of hair wasn´t mentioned
Collie (hybrid) - October 1997
300 (triads)	5 - 6	1500 - 1800	70-100 / 0,099 1	70-100 / 0,054 2	20-30 / 0,018-0,036 8-12		-	-
Shar-pei - December 1997
240 (triads)	5 - 6	1200	the ratio of individual kinds of hair wasn´t mentioned
German longhaired pointer - December 1997
687 (triads a diads)	5	3437	the ratio of individual kinds of hair wasn´t mentioned

The largest amount of hair from the researched group has Czechoslovakian wolfdog and red fox. The fox has also at the most hair on belly. The same length or longer hair on belly as on the back has Czechoslovakian wolfdog, New-foundland, Poodle, Siberian husky, Alaskan malamute and Irish setter. At the other cases the hair on belly is shorter. At all cases the hair is thinner on belly. At some dogs the hair is graded to five, four or three lengths, at other all hairs grow the same length (Malamute, Foxhound, Japan chin). For a loyal to dog genus we can consider those individuals, which have on their back dermatoms, created with triads of nests. Where these triads are not so visible, it comes to the first genetic difference from the original dog line, which allows the surviving in wild.

Worked out according to the article of Prof.MVDr. Vladimir Komarek DrSc. with his kind agreement. The article and dates are shortened, the whole article was printed in Magazine "Pes pritel cloveka" 3/2000.