[The duration of feedings and the intervals between them in mice during established lactation]

Lactating female mice were shown to spend most of the time in the nest with their litter attached to the nipples. Nursing periods lasted for 1 hr on the average, spaced by half as long breaks. These parameters were not stable within 24 hrs. The longest internursing period was about 2 hrs. The importance of the data concerning animal's behaviour when making physiological and biochemical experiments, is discussed.