Weight Variation in Adrenal Glands of the Mongoose in Hawaii 
P. Quentin Tomich 1 
ABSTRACT: Gross morphology and weight characteristics are described for adre- 
nal glands in a population of the small Indian mongoose, Herpestes auropunctatus 
( Hodgson ) . Mongoose adrenals are anatomically similar to those in the cat and 
dog, and may be typical of those in the Order Carnivora. The right gland is about 
80% as large as the left. Relative adrenal weight decreases in all age and sex 
classes as body weight increases. Adrenals are only slightly larger in young females 
than in young males, but at sexual maturity they enlarge greatly in females and 
remain much larger than those in males. In lactating females the adrenals are 
significantly larger than those in all other classes of adult females. There seems 
to be no major effect of sexual maturity on adrenal size in males. Over a three- 
year period the population demonstrated a remarkable stability of adrenal gland 
weight in the face of increasing drought and decreasing numbers. Minor adrenal 
response to seasonal fecundity, environmental stress, and variations in population 
density may be a character of carnivores quite in contrast to that observed in the 
highly sensitive rodents. 
There have been two recent analyses of how 
the pituitary-adrenocortical-gonadal system ef- 
fectively regulates growth and decline of free- 
living mammalian populations. Christian (1961) 
emphasizes the intrinsic mechanisms of density 
and social interaction as the indirect effecters of 
population control. Negus, Gould, and Chip- 
man (1961) attribute this regulation primarily 
to the extrinsic factors of climate and nutrition. 
Further progress in understanding adrenal gland 
function as it applies to population theory de- 
pends in part on a clearer knowledge of adre- 
nal form and size patterns as they occur in the 
several orders of mammals. 
This report on the small Indian mongoose, 
Herpestes auropunctatus (Hodgson), increases 
what is known about the carnivores, which 
have apparently been omitted from population 
studies dealing with the adrenals. The mon- 
goose was introduced into Hawaii in 1883 from 
stocks earlier transplanted to Jamaica from 
India, and it became rapidly established on four 
of the main islands. 
J Plague Research Unit, State Health Department, 
Honokaa, Hawaii. Manuscript received January 29, 
1964. 
METHODS 
Samples of mongoose adrenals were collected 
monthly in Hamakua District on Hawaii Island 
between April, I960 and March, 1963 during 
ecological studies of the reservoirs and vectors 
of bubonic plague. The mongooses were trapped 
alive, killed with CaCN dust, taken to the lab- 
oratory and weighed. Adrenals were removed, 
trimmed of adherent tissue, and preserved (in 
10% neutral formalin, except for a small num- 
ber of those collected in the third year, which 
were placed in Bouin’s fluid). After fixation 
each pair of glands was blotted on paper towel- 
ing and weighed immediately on a torsion bal- 
ance to an accuracy of 0.1 mg. Weights were 
then expressed in milligrams per 100 grams of 
body weight (mg%), and are presented through- 
out the report in this relationship. 
For statistical analysis the 36 monthly sam- 
ples comprising 784 pairs of adrenals were 
sorted according to age, sex, and reproductive 
state of the individual mongoose. Age classes 
were two: immature and adult. Males with the 
bare testes less than 8 mm long were classed 
as immature (and hence sexually inactive), and 
all others were considered adult; criteria were 
approximately those of Pearson and Baldwin 
238 
