Observations on certain physiological processes of the marmot. I.—The heart

Abstract

In the autumn of 1929 thirteen marmots were brought to Cambridge by one of us (Endres) after the hibernation period had commenced. Of these, we owe four to the kindness of Prof. Adolph Löwy of the Schweizer Forschungsinstitut at Davos. The remainder came from Roffna near the Julier Pass. During the first few days of their captivity in Cambridge they were kept at about 5° C. in the Low Temperature Station, and for this hospitality we would like to thank Sir William Hardy. This temperature proved too low. One of the most remarkable facts about marmots, which has been described by Mangili is that they can be awakened, not only by heat but by cold; at temperatures slightly above 0° C. several of the marmots woke. We shall have to refer to this phenomenon later. The marmots were then placed in an unheated wooden “Army hut,” in a wooden box which was contained in a much larger box. Between the two boxes was sawdust. Also sawdust and hay were put in the small box. The smaller box was covered with a lid, and there was a hole in the side, through which the marmots could leave the inner box for purposes of defæcation or micturition. It is stated in the literature that a marmot wakes up about once in three weeks for this purpose. Our experience was that, when the animals first came, they performed the functions of micturition and defæcation more frequently that at a later stage in the winter. They were losing water all the time, which was not replenished. The temperature of the box containing the marmots was always above that of the outside air. During the winter of 1929-30 there was very little frost, and the lowest temperature noted on the “minimum” registering thermometer in the outer box was 2° C., and that only once.