Hawaiian Monk Seal — Kenyon and Rice 
On one occasion, we were weighing pup 
MS- 12 recently deserted by its mother. Pup 
MS" 13 and his mother were more than 100 
yards away in the lagoon. Hearing the bleat- 
ing of MS- 12, the mother of MS- 13 swam 
rapidly toward us, head raised and bellowing, 
her pup following closely behind. She con- 
tinued her charge onto the beach for 10 feet 
or more, to within about 2 yards of us. 
On another occasion, when MS- 12 and his 
mother were swimming near the shore, we 
went to the water’s edge to photograph the 
two. With head held high and mouth open 
in threat display, the mother charged to the 
beach, left the water, and pursued us up the 
beach for a distance of 20 feet (Fig. 12). She 
quickly returned to the water, but repeated 
the performance when we again went to the 
¥/ater’s edge. Re-entering the water, she was 
about 50 yards from shore and did not see us 
as we approached the water’s edge a third 
time. Therefore, we yelled loudly at her and 
Fig. \2a. A mother monk seal, her pup dimly visible 
beneath the surface behind her, displays threat be- 
havior when charging human observers on the beach. 
Midway Atoll, May 4, 1957 (KWK 57-17-29). 
241 
once again she charged to shore as before. 
We found that this behavior was quite de- 
pendable and facilitated the capture of her 
pup for weighing, since the pup always fol- 
lowed close to its mother. The same behavior 
was noted among mother seals at Kure, with 
the exception of one female which bellowed 
and opened her mouth in threat display at a 
distance of about 50 yards offshore, but re- 
fused to charge onto the beach. 
One exceptionally aggressive mother be- 
gan a charge on the beach while her newly 
born pup was in front of her. If we had not 
changed the direction of her charge by mov- 
ing to one side, she would have crushed her 
pup. Although she crushed it only slightly 
under her chest, it appeared for a few mo- 
ments to be dazed by having its breath ex- 
pelled under her weight. 
At Pearl and Hermes Reef in late May, 
1956, "Torn Frazier, a fisherman, was attacked 
by an adult seal while spear fishing in about 
six feet of water near a beach where several 
new pups and adults were observed. The seal 
swam rapidly and directly at Frazier with its 
mouth open and turned away only after being 
poked repeatedly with a fish spear,” (E. C. 
Jones, FWS, in lit.) 
The mother of MS- 13 would charge at us 
anywhere along a nearly half-mile stretch of 
beach, at a considerable distance from the place 
her pup was born. The display of hostility 
should probably be interpreted as behavior in 
defense of her pup rather than defense of 
a territory. 
PHYSICAL CHARACTERS AND GROWTH 
Dentition 
The tiny milk teeth are apparently resorbed 
before birth, as in other phocids. When the 
skull of a 9-pound prematurely born pup 
(BDM 491) was cleaned, only one of these 
small teeth could be found. 
At birth, the gums of the monk seal pup 
are almost smooth. Slight irregularities on the 
surface indicate the position of unerupted 
teeth, especially the postcanines. At age 27 
