MAMMALS OF THE GULF OF MEXICO 



Gordon Gunter, Institute of Marine Science, The University of Texas 



The mammalian fauna of the Gulf of Mexico 

 consists of the manatee, the West Indian seal, and 

 various cetaceans. In this account repetitions of 

 keys and anatomical descriptions are omitted. An 

 attempt has been made to include only information 

 relating particularly to the Gulf. 



Order PINNIPEDIA 

 Family PHOCIDAE. Hair Seals 

 Monachus tropicalis (Gray). West Indian Seal 



The monk seals are restricted to warm waters 

 of the Northern Hemisphere, and there are only 

 three species. These are Monachus monachus 

 (Hermann), of the Mediterranean and Black Seas, 

 M. schaxdnslandi Matschie, of the Hawaiian Is- 

 lands, and M. tropicalis, of the Gulf and West 

 Indian region. 



So far as scanty historical information goes the 

 former range of the West Indian seal was from 

 the Bahamas and southern Florida through the 

 West Indies to Honduras and Yucatan. Gunter 

 (1947) has given information indicating that single 

 individuals and small herds occasionally visited 

 the western Gulf as far north as Galveston, Texas, 

 as late as 1932. 



Large adults measure up to 7.5 feet in length. 

 The color is "brown, tinged with gray, caused by 

 the hairs being light at the extreme tip. The 

 color becomes lighter on the sides, and gradually 

 passes into pale yellow or yellowish-white on the 

 ventral surface of the body." (J. A. Allen, 1887.) 



Little is known of the natural history of the 

 West Indian seal. J. A. Allen (op. cit.) and True 

 and Lucas (1884) summarized practically all of 

 the information. Several females with fetuses 

 nearing full term were killed in December 1886 

 on the Triangle Keys off Yucatan. Food habits 

 are unknown. Monod (1923) observed M. mona- 

 chus, the Mediterranean species, chasing fish. 



This animal was also called "sea-wolf" for no 

 good reason, for it is mild and unsuspicious when 



on the beach. Glover Allen (1942) pointed out 

 that the many Seal and Lobos Keys are reminis- 

 cent of its former presence. This unfortunate 

 species was easily procurable and was the best 

 source of oil in the southern islands during colonial 

 times. This led to its early and rapid decimation. 

 The famous English geographer and freebooter. 

 Sir William Dampier, noted the fact in 1675. He 

 found the seals in abundance in the Alacranes 

 Islands and said, "the Spaniards do often come 

 hither to make Oyl of their Fat." They were 

 already becoming scarce when P. H. Gosse wrote 

 about them in Jamaica in 1846. The story of 

 their decline to near extinction is succinctly re- 

 corded by Glover Allen (op. cit.). The last speci- 

 men taken was killed at Key West, Florida, in 

 1922 (Townsend 1923). The last sight record was 

 on the Texas coast in 1932 (Gunter, op. cit.). 



However, it seems probable that a few still 

 survive on the Triangle Keys and the Alacran 

 Islands off the coast of Yucatan. Dr. Raymond 

 M. Gilmore told the writer that residents of Car- 

 men, Yucatan, reported seeing seals in the Ala- 

 crans as late as 1948. They were reported to 

 come ashore in greatest numbers in April. Others 

 may exist (Moore 1953). They should be rigidly 

 protected. 



Order SIRENIA. Sea Cows 



Family TRICHECHIDAE. Manatees 



Trichecus manatus Linnaeus. West Indian Manatee 



Harlan (1824) described the Florida manatee as 

 different from the West Indian or South American 

 manatee and gave it the species name latirostris. 

 True (1884) agreed that there were two species, 

 but neither of these workers showed where the 

 difference lies. True considered that the so-called 

 Florida manatee also Uved in the West Indies, 

 while the South American manatee lived from 

 along the mainland to far up into Mexico. This 

 opinion also implies that the habitats are different 



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