BP asks...
I ain't picking no fight...All the critters we are talking about are canines and don't hibernate. How can one dog breed "hole up" and not eat for a few days in sub-freezing tempatures while the other 2 dog breeds increase their traveling/hunting/eating by adding daylight hours?
Because you are talking about three different critters. They don't hibernate, you're right. They will hole up during extreme conditions,all 3, even Wolves. High winds, heavy snow, heavy rain will force these critters to lay up from hunting/traveling. Their nature is to wait it out. Wait to hunt or to breed. They sense approaching weather fronts and feed up before foul weather. During extended cold periods, they will hunt/travel when hunger urges 'em. Breeding season has a large window, and it will occur, sooner or later.
Grey Fox can hole up because of fat reserves. Any one that has skun a Grey can testify to Fat and having to flesh 'em. Greys live in a small area and don't have to travel far.
Red Fox have little Fat and have to keep moving. Reds do lay up for a day or two or three but have to keep moving and that's part of their nature. Skun a Red and see how much Fat is on the hide.
Coyote hole up too for several days. Coyote do have Fat, just skun a flee biten, stinky Coyote.
Canines, by adding daylight travel hours during or mid-January to late February will get the breeding done and food in their belly.
I am not an expert. These are my obersvations and knowledge from studies I read. Am interested in learning more.
