216 
PACIFIC SCIENCE, VoL XIII, July 1959 
Seven monk seals have been captured on 
Erench Frigate Shoals, with the assistance of 
the U. S. Coast Guard, and one at Pearl and 
Hermes Reef. These were held in captivity in 
the Honolulu Zoo, the Waikiki Aquarium, 
and the San Diego Zoo. One seal is still living 
in the Waikiki Aquarium after more than 
two and a half years in captivity, and another 
in the San Diego Zoo. Others have been kept 
for relatively short periods (Table 1). 
TAXONOMY 
Monk seals are the only phocids of tropical 
and subtropical waters. The genus Monachus 
is represented by three relict populations with 
a widely disjunct distribution. Their probable 
origins and relationships have been discussed 
by King (1956). It appears that the Mediter- 
ranean monk seal, M. monachus, is specifically 
distinct from the Caribbean monk seal, M. 
tropicalis, and the Hawaiian monk seal, M. 
schauinslandi. The differences between the lat- 
ter two are slight and have not been verified 
by comparison of adequate series of speci- 
mens of known sex and age. From the few 
specimens we have examined, certain dis- 
tinguishing characteristics ascribed to M. 
schauinslandi— QsptcidXlj shape of the pal- 
ate and the shape of the zygomatic branch of 
the squamosal — do not appear to be constant. 
The form of the anterior border of the nasals 
and the shape of the infraorbital foramen are 
the most obvious distinguishing features. The 
morphological differences between the Carib- 
bean and the Hawaiian monk seals are less 
than one would expect in two groups of 
animals so widely separated. Further study 
may indicate that M. schauinslandi should be 
regarded as a race of M. tropicalis, 
Monachus is currently recognized as the 
only genus of the subfamily Monachinae 
(Simpson, 1945). The close relationship be- 
TABLE 1 
Record of Monk Seals Held in Captivity^ 
DATE CAPTURED 
DATE DIED 
SEX 
APPROX. 
AGE2 
WEIGHT, 
LBS. 
LENGTH, 
CM.^ 
WHERE 
HELD 
REMARKS 
May 12, 1951 
August, 1951 
juv 
1104 
143 
S. D. Zoo 
Cause of death un- 
determined 
May 12, 1951 
ad 
o 
o 
rCi 
Honolulu 
Zoo 
Refused foods; lib- 
erated near Kane- 
ohe Bay, Novem- 
ber, 1951 
April, 1955 
July, 1956 
9 
juv 
902 
Waikiki Aq. 
Died of ulcers 
October, 1955 
October, 1957 
subad 
2006 
Waikiki Aq. 
Postmortem: large 
gastric ulcer 
August, 1955 
9 
subad 
2306 
Waikiki Aq. 
Alive in November, 
1957 
September 12, 1956 
October 22, 1956 
juv 
96 
131 
S. D. Zoo 
Cause of death un- 
determined 
September 22, 1956 
November 9, 1956 
9 
subad 
1602 
1685 
S. D. Zoo 
Acute pneumonia, 
vegetative endo- 
carditis and peri- 
tonitis 
July 21, 1957 
d’ 
subad 
119' 
S. D. Zoo 
Alive in January, 
1958 
^ All taken at French Frigate Shoals, Territory of Hawaii, except male taken October, 1955, which was captured at Pearl and 
Hermes Reef 
2 Estimated at capture. 
® Measured at death. 
^ Eviscerated — estimated total weight 125 lbs. 
^ Estimated at death. 
•5 Estimated July, 1957. 
"^Weighed at capture. Estimated weight 180 lbs., December 31, 1957. 
