526 
Journal of Agricultural Research 
Vol. XXVII, No. a 
very fond of certain foods which others have not learned to like or will 
not eat. Some individuals are very talkative, always squeaking or 
making some noise at the others, while more of the individuals are 
quiet and generally silent. Some are far more pugnacious than others 
and often bite if handled, while others may be held in the hands and 
stroked without offering any resistance. These differences are noticed 
in the young just beginning to run about, and seem to be to some ex¬ 
tent inherited characteristics. Certain pairs will live together in perfect 
accord, while others will quarrel and fight and refuse to occupy the same 
nest. Some females will accept the attentions of only one male and will 
savagely resent the advances of all others, while others show no prefer¬ 
ence and will accept attentions promiscuously. 
Most of the males are highly polygamous, but one pair that lived to¬ 
gether until after the young were born were from the first very affec¬ 
tionate, remaining much of the time together in the nest box and paying 
little attention to the mice in neighboring cages. This male would not 
voluntarily leave his cage nor enter the cage of another female, even 
when called. This was very unusual, as most of the males were eager 
to go into other cages and make friends with the females or fight with 
the males. 
In No. 6 cage a male and female had lived contentedly together and 
raised two families of young, while against their cage an old female lived 
alone in No. 3 and was on friendly terms with her neighbors through the 
wires. After she had given birth to her fourth family of eight young 
she was making her peculiar squeaking calls, which the male in the other 
cage evidently recognized as an invitation to visit her, and as he eagerly 
came up over the edge of his cage and down into hers the female in cage 
No. 6 became greatly excited and twice forced her way out under the 
roof of her cage and tried to get into cage No. 3 to punish her rival. Not 
being allowed to do this she stormed around her own cage, squeaking, 
kicking up the sand on the floor, biting the wires, and showing every 
indication of rage until her mate came home in the evening. Then she 
pounced upon him, bit his nose, chased him around the cage, squeaking 
and scolding at him until he was severely punished. She was cross 
with him all the evening, but the next day had settled down to her usual 
pleasant frame of mind and had evidently forgotten her domestic 
troubles. 
A neighboring male that came into cage No. 1 during the mating time 
of the old pair that had been captured in their wild state was pounced 
upon by the female and his foot so badly bitten that he was glad to es¬ 
cape to his own cage and nurse his bloody paw. In other and the ma¬ 
jority of cases the females made no objection to their mates visiting other 
females as much as they wished, and these two cases are exceptions to 
the usual free-love manner of life among these polygamous little animals. 
These incidents, however, show variable tendencies in the social life 
of the meadow mice, which, under certain conditions of environment, 
might lead to perfect monogomy if for any reason this should prove 
beneficial to the species. 
PLAYING 
With such quick and energetic little animals it is sometimes difficult 
to distinguish between work and exercise and mere play. The young, 
soon after their eyes are open, will push and pull and roll each other 
about in unmistakable sport and up to half-grown size are conspicuously 
