Adrenal Glands of Mongoose — TomicH 
241 
TABLE 1 
Adrenal Size (in mg/ 100 g body wt) in Adult Male Mongooses by Season 
SEASON 
NUMBER 
RANGE 
MEAN 
SE 
Breeding (Jan.-July) 
86 
11.9-62.3 
27.9 
± 0.76 
Nonbreeding (Aug.-Dee.) 
40 
14.1-52.9 
25.7 
— 1.73 
those taken in the breeding season and those 
taken after it (Table 1). 
As body weight of males increases there is 
an almost continuous trend in reduction of rel- 
ative adrenal weight (Fig. 2). The transition 
to adulthood is smooth, showing that adrenal 
size is not greatly influenced by sexual matur- 
ity. In contrast, although the trend in young 
females matches closely that in young males, 
adult females demonstrate an explosive increase 
in adrenal size. Once this increase is established, 
the mean trend in its reduction as body weight 
increases covers almost the same amplitude as 
that in adult males (though distributed over 
four weight range classes instead of six ) . 
In the advanced fetus, adrenal glands are 
noticeably large and their relative weights ex- 
ceed those of all other age classes examined 
(P < 0.01). Three fetuses near term and aver- 
aging 20.1 g in body weight had a mean rela- 
tive adrenal mass of 125.0 ± 11.4 mg % (1 
SE). 
DISCUSSION AND CONCLUSIONS 
The cat (Northup and Van Liere, I960) 
has a slightly larger adrenal mass in adult fe- 
males than in adult males, and in smaller mem- 
bers of both sexes than in the larger ones. 
Baker (1936) examined 1250 dogs of a wide 
variety of breeds and ages, and found condi- 
tions in immature animals similar to those 
which I found in the mongoose. When body 
weight of dogs increased, relative adrenal weight 
decreased in all classes; but, as in cats, adult 
females had only slightly larger adrenals than 
did adult males. This may be related to the 
status of both these species as domestic ani- 
mals. Among wild species the basic pattern of 
adrenal weight variation in the vole, Microtus 
montanus (McKeever, 1959), is similar to that 
in Herpestes auropunctatus , although in the vole 
prominent seasonal variation occurs as it does 
in most short-lived rodents, and this is not 
found in the mongoose. 
Mongooses used in this study were collected 
in a period of almost continuously subnormal 
rainfall and increasingly serious drought con- 
ditions. The moderately dense population de- 
creased markedly in most sections of the dis- 
trict (Tomich, ms). Yet no significant differ- 
ences were observed in adrenal size among the 
three years within any of the age and sex 
classes (Table 2). The female reproductive 
stage classes were likewise remarkably uniform 
in the three years, and also showed no signifi- 
cant differences (Table 3). Statistical interac- 
tion was not evident. 
This rigid stability within the various classes 
may be interpreted in terms of stress theory to 
mean that environmental and sociological ef- 
fects were actually slight and easily accommo- 
dated, or that the mongoose is refractory in the 
nature of its pituitary-adrenocortical-gonadal 
system to effects commonly measureable in 
rodents. Fat is not a complicating factor in 
these relationships because few animals had 
fat deposits and these deposits were seldom 
large. 
Unexpectedly, there was within each class a 
downward trend by years in mean adrenal val- 
ues ( see Table 2). In the first year (all classes 
combined) adrenals were larger than in the 
two succeeding years (P < 0.01 for each). The 
implication of this observation is that a nor- 
mally wet year with a high population was less 
favorable to the mongooses than the following 
dry years with a reduced population. In view 
of the generally slight adrenal response within 
the various classes, I prefer to withhold judg 
