Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Distribution of burrowing (a), climbing (b) and upright standing (c) throughout the day at 8 months of age. The dark period was from 11 to 23 h. Data represent mean ± s.e. based on values obtained from six cages housing five (n = 4) or four (n = 2) rats.
