Table 1:

Dogs included in the pair-housing study

Dog ID	Dog name	Sex	Reproductive status	Age (years)*	Length of stay (months) at first hair collection
Paired 1A	Nike	Male	Neutered	1.8	12
Paired 1B	Selly	Female	Spayed	2	10
Paired 2A	Thunder	Female	Spayed	2	9
Paired 2B	Snow	Female	Spayed	2	13
Paired 3A	Georgia	Female	Spayed	2	14
Paired 3B†	Clove	Female	Spayed	4	16
Paired 4A	Kato	Male	Intact	1.8	8
Paired 4B	Tucker	Male	Neutered	2	10
Solitary 1	Mystic	Male	Intact	2	9
Solitary 2	Lucy	Female	Intact	3	17
Solitary 3	Lilly	Female	Intact	4	8
Solitary 4	Bumper	Male	Neutered	2	20

All dogs were housed in solitary kennels during the baseline study period; experimental dogs were pair-housed and control dogs remained solitary during the treatment period. Pairs are identified according to the dog they were paired with, once moved into pair housing (eg, dogs ‘Pair1A’ and ‘Pair1B’ were housed together after the change).

*Exact age is rarely known for colony dogs (except for dogs ‘Paired 1A’ and ‘Paired 4A’, who were born onsite); age is estimated by the veterinary staff when the dog is first added to the colony.

†This dog was being treated for anxiety with the tricyclic antidepressant amitriptyline (50 mg orally, twice daily) before the study commenced and for the duration of the study.