To sleep, perchance to dream?

[sanford]

I've always been aware that many dogs, in addition to sleeping through the night, also sleep a great deal of the time during the day.

Now that I have my own dog, I'm seeing this first-hand. I'm curious as to why this is so. Do dogs, in their natural state, require so much sleep? If so, why? I can't see what biological purpose so much sleep serves. Has anyone/ any animal behaviorists ever studied this? Of course, boredom may be one cause...My dog has interactive toys, is walked & played with throughout the entire day. As soon as activity stops - he sleeps/naps.

Just curious.

[bradl]

Excellent question - am curious myself. I understand that canids are generally crepuscular with activity peaks around dusk and dawn. There are apparently some breed variations as well, with some of the larger dogs sleeping nearly 18 hours a day. Active dogs left to their own devices may sleep 'only' 12-14 hours a day.

One article I read on wolves found that activity correlated fairly well with temperature, and/or may be influenced by prey activity.

Even during continuous daylight at 80o N. latitude, the wolves showed a definite circadian rhythm in their activities (Mech and Merrill 1997;Mech and al. 1998). Wolves occupy a wide range of latitudes, varying substantially in the seasonal changes in light:dark ratios and temperature. Within the basic constraints of the daily and seasonal cycles, the activity patterns of wolves appear quite flexible, adjusting to changes in reproductive stage, nutritional condition, activity of prey, probability of threats and temperature (Table 3.2).

On very cold or very hot days, wolves may appear extraordinarily lazy (Mech 1988: 58). Locating radio-collared individuals by airplane on winter days in Superior National Forest, Mech (1992) was much more likely to find them inactive (65%) than traveling (28%) or engaged in activities such as feeding or socializing. Similarly, during the summer denning season on Ellesmere, we passed many chilly hours watching wolves "mimic boulders", curled in tight balls at favored sleeping sites throughout the day.

In northwestern Alaska, 23 wolves monitored continuously by satellite were more active in summer than winter and activity was positively correlated with temperature (Fancy and Ballard 1995). During summer, crepuscular activity peaks occurred at 0600 and 2200. Activity was more likely in the morning than afternoon during the summer, but occurred throughout the day in winter. Lower activity during midday was interpreted as due to heat intolerance during summer days (Harrington and Mech 1982b). Whether such seasonal shifts in activity are due to the wolves' own intolerance of heat or due to the activities of their prey is hard to determine (Fuller 1991;Oosenbrug and Carbyn 1982;Scott and Shackleton 1982). Also, when individuals are in very poor nutritional condition, they are less likely to be active (Mech 1977b).

from http://canis.tamu.edu/wfscCourses/Concepts/Packa98.html

I think dog vision is very well adapted to low-light conditions (as at dawn and dusk) and their activity may be tuned to times when their acuity is a special advantage - and timed to the activity of the types of things they would normally chase and might eat: rats, squirrels, rabbits (also apparently crepuscular) and so on.

Clearly dogs are adaptable to each family's situation. I know our dogs are only too glad to see the back of us on Monday following a busy weekend where they are 'on alert' and joining in activity throughout the day when they would normally be sleeping.

[Eliz222]

MIne are alot more active when it's cooler out, so the heat is making them sleep more. We take them on walks (DD) in the late evening. I have been puttuing them outside for 10 min at a time (with a bucket of ice) and they seem to do ok with this..but I worry about too much heat. I have been doing this several times a day just to get them outside. We are going to have MUCH cooler weather this weekend so I'm sure they will be going nonstop then!