Hawaiian Monk Seal — Kenyon and Rice 
tween Monachus and the Antarctic phocids of 
the subfamily Lobodontinae has been pointed 
out by King (1956). Biological similarities, 
such as voice and certain aspects of behavior, 
are shared by the monk seal and Weddell 
seal {Leptonychotes weddelli), while the monk 
seal shares with elephant seals {Mirounga) a 
unique method of molt. It is evident that the 
Monachinae are even more closely related to 
the Lobodontinae and Cystophorinae than 
previously recorded biological data had indi- 
cated, and that the three subfamilies are more 
closely related to each other than any one of 
them is to the northern *'hair seals” (sub- 
family Phocinae). Trouessart (1897) placed 
the Antarctic phocids and the monk seals to- 
gether in the subfamily Monachinae, an ar- 
rangement with which V. B. Scheffer agrees 
{in lit.). 
distribution 
The breeding range of Monachus schatiins- 
landi is confined to the islands and atolls of 
the Leeward Chain, which extends for 1,200 
miles northwestward of the main Hawaiian 
Islands, The Leeward Chain consists of two 
geologically distinct portions (Bryan, 1942). 
In the eastern half are four high volcanic 
islands: Nihoa Island, Necker Island, La 
Perouse Pinnacle, and Gardner Pinnacles. 
These rise precipitously from deep water. The 
only extensive area of shallow water is French 
Frigate Shoals, a crescent-shaped atoll con- 
taining a dozen sand islets, which half sur- 
rounds La Perouse Pinnacle. Paty (1857) gave 
the following account of a visit to Nihoa on 
April 27, 1857, . .on the sand beach ten or 
twelve hair seals were found; they didn’t take 
much notice of us until His Majesty [King 
Kamehameha IV] had shot several, when they 
became more scared.” None were seen at 
Nihoa between August 7-17, 1940, although 
looked for (Vanderbilt and de Schauensee, 
1941), and Frank Richardson {in lit) who 
visited the island in late 1953 and again in 
early 1954 found none. A small breeding 
colony occupies French Frigate Shoals. They 
217 
are not reported from Necker or Gardner. 
The western half of the Leeward Chain con- 
sists of six low coral atolls. From Maro Reef, 
where only a few rocks are awash at low tide, 
two monk seals were reported in 1951 (Bailey, 
1952). Lt. Comdr. D. E. Moritz flew over 
Maro Reef twice in October, 1957, and re- 
ported seeing no seals. Virtually all Hawaiian 
monk seals breed on the outermost five atolls : 
Laysan Island, Lisianski Island, Pearl and 
Hermes Reef, Midway Atoll, and Kure Atoll. 
Wandering seals are occasionally seen 
among the main Hawaiian Islands. At Hilo 
Bay, Hawaii, one was killed and eaten by the 
natives in 1900 (Henshaw, in Dill and Bryan, 
1912). Here, perhaps, is an explanation of the 
restricted breeding range in the Leeward 
Chain, which had no aboriginal human popu- 
lation. Recent reports from waters of the 
main islands are shown in Table 2. 
environment 
Climate 
The fairly uniform subtropical maritime 
climate at Midway Atoll is typical of the 
western half of the Leeward Chain. Tempera- 
tures near freezing are unknown. Reef corals 
and their associated fauna grow fairly well but 
are near the northern limit of their range. 
They do not occur north of Kure Atoll. Two 
seasons are well marked. Winter, from early 
December through March, is characterized by 
low temperatures, frequent rains, and winds 
which sometimes reach velocities of 90 miles 
per hour. These gales cause heavy swells 
which break violently over the protecting 
reef and result in rough water in the lagoon. 
Summer, from April through November, is 
warm, very humid, and sunny, with occa- 
sional showers. The northeast trade winds 
blow quite steadily but mildly, and the sur- 
face of the lagoon and ocean is calm. Mean 
daily maximum and minimum air tempera- 
tures, and mean water temperatures, are pre- 
sented in Table 3. 
During the period March 23 to June 15, 
1957 , surface water temperatures in Midway 
