Hawaiian Monk Seal — Kenyon and Rice 
231 
1956 195 7 
Fig. 7. Counts of seals. Midway Atoll, November, 1956-October, 1957. 
yellow to whitish gray, brown, and purplish 
black. No hard parts of food items were 
observed in feces. 
In Captivity 
Two monk seals held captive in the Waikiki 
Aquarium showed a preference for eels. How- 
ever, because other fish were less expensive 
and easier to obtain, the animals were usually 
fed smelt {Osmerus mordax) and California 
horse mackerel {Trachurus symmetricus) from 
California. The female ate both smelt and 
mackerel while the male preferred mackerel. 
Together, the two seals consumed about 
25 pounds of fish per day, roughly one- 
seventeenth of the body weight. When living 
fish were placed in their pool, the seals 
showed a preference for them. All-purpose 
vitamin B capsules were placed in fish and 
fed to the animals daily (S. W. Tinker and 
K. A. Wong, in lit.). A captive Mediterranean 
monk seal was said to prefer eels over other 
fish and consumed about 14 pounds of fish 
daily (King, 1956). 
BEHAVIOR 
Locomotion 
While swimming slowly in shallow water 
near shore, forward motion is attained pri- 
marily with the forefiippers. However, when 
more speed is desired, the hind flippers and 
posterior part of the body undulate laterally 
as in other phocids. The forefiippers were 
seen to be in strong rapid motion through a 
vertical plane perpendicular to the body axis 
while seals were swimming rapidly in clear 
water over a white coral sand bottom. It ap- 
peared to us that the forefiippers were being 
used to increase speed as well as to steer. 
While skin diving, the junior author has 
observed four seals swimming under water at 
close range. Two of these were kept under 
observation for a considerable time. Although 
the lateral undulations of the body trunk and 
