EUGENE M. MCCARTHY, PHD GENETICS
Arctocephalus australis [South American Fur Seal]
× Otaria flavescens [South American Sea-Lion] NHR. CON: southern South America. Copulations have been observed in the wild. Miller et al. (1996, p. 472) says most of the participating females died, “but some survived so that they could have produced hybrid offspring. In addition, several probable hybrids were noted. At Cabo Polonio, a likely hybrid between Otaria and A. australis was captured and handled by F. Machado, a sealer of 50 years’ experience.” The animal was a juvenile male with a coat like a fur seal’s, but a sea-lion’s head. Cabo Polonio is on the eastern coast of Uruguay.
Note: Hunting led to the extirpation of seals on Macquarie Island, but they are now returning. Most breeding animals are A. gazella or A. tropicalis. These, and A. forsteri, occur in the same area, where mixed mating between them is common (Goldsworthy et al. 1999; Page et al. 2001).
Arctocephalus forsteri [New Zealand Fur Seal]
× Arctocephalus gazella (♀) [Antarctic Fur Seal] ONHR(southwestern Pacific). CON: southeastern Australia. Also, although most hybrids on Macquarie Island are A. gazella × A. tropicalis, hybrids of this type do occur there. Brunner reported six variably intermediate skulls (from probable hybrids). Brunner 1998; Goldworthy 1999; Goldworthy et al. 1998, 1999 (p. 263); Page et al. 2001, 2002; Shaughnessy et al. 1998.
× Arctocephalus tropicalis (♀) [Subantarctic Fur Seal] ONHR (MacQuarie Island). Gales et al. 1992 (p. 135); Goldworthy 1999; Shaughnessy 1992.
+ Phocarctos hookeri (♂) [New Zealand Sea-Lion] CON: southern New Zealand (and islands to south). Wilson observed a P. hookeri male copulating with the carcass of a female A. forsteri (dead as a result, probably, of the attempted mating). Miller et al. 1996; Wilson 1979.
Arctocephalus gazella [Antarctic Fur Seal]
See also: Arctocephalus forsteri.
+ Aptenodytes patagonicus [King Penguin] Male Antarctic fur seals have been observed copulating with king penguins on Marion Island. See the separate article “Bird-Mammal Hybrids."
× Arctocephalus tropicalis (♂) [Subantarctic Fur Seal] ENHR(Marion Island, Macquarie Island, Prince Edward Island). HPF(♀♀). CON: southern oceans. Goldworthy et al. (p. 262) say most hybrid pups detected by molecular techniques “were not recognized as phenotypic hybrids based on external features.“ Thirteen of 39 (33%) pups tested by Goldworthy et al. were the products of this cross. Of these 13, only three were phenotypically hybrid. Hybrid males may be partially fertile; they have been seen copulating with non-hybrid females. Lento et al. found that at MacQuarie Island mtDNA haplotypes characteristic of each of these seals were found in the both. Condy 1978; Gales et al. 1992; Goldsworthy et al. 1998, 1999; Guinet et al. 1994; Hofmeyr et al. 1997, 2006; Kerley 1983, 1984; Kerley and Robinson 1987; Lento et al. 1997; Page et al. 2001, 2002; Shaughnessy and Fletcher 1987; Shaughnessy et al. 1988; St. Clair Hill et al. 2001; Wynen et al. 2001.
Arctocephalus philippii [Juan Fernandez Fur Seal]
× Arctocephalus tropicalis [Subantarctic Fur Seal] ONHR(Juan Fernández Archipelago). Probable hybrids have been reported. Francis (in Boness et al. 1993); Torres et al. 1984.
Arctocephalus pusillus [South African Fur Seal]
+ Mirounga leonina [Southern Elephant Seal] An M. leonina male was observed copulating with numerous A. pusillus females (though actual hybrids derived from such mating do not seem to have been reported). He crushed them to death in the process. M. leonina males are far larger than Arctocephalus pusillus females (2,000-2,700 kg vs. 36-122 kg). These seals belong to separate families (Mirounga leonina belongs to Phocidae and Arctocephalus pusillus belongs to Otariidae). Best et al. 1981.
× Zalophus californianus (♀) [California Sea-Lion | Galapagos Sea-Lion] CHR. DRS. Jennison (p. 220) describes a male hybrid: “It is very lively in the water, fond of swimming on its back and stroking its nose with the fore flippers, a trait common to Cape Sea-Lions, which I have never noticed among Californians. The pup was pearly-grey and bears a close resemblance to the male parent” (i.e., A. pusillus). Jennison 1914; Schliemann 1968†. Internet: tinyurl.com/hey3grd.
Arctocephalus townsendi [Guadalupe Fur Seal]
× Callorhinus ursinus [Northern Fur Seal] NHR(western U.S., Pacific Coast). Jameyson et al. (1981) report an animal that was either this hybrid or Callorhinus × Zalophus. DeLong 1982; DeLong (cited by Goldsworthy et al. 1999, p. 262); Stewart et al. 1987.
+ Zalophus californianus (♀) [California Sea-Lion | Galapagos Sea-Lion] Copulation has been observed. Boness et al. 1993 (p. 81); Stewart et al. 1987.
Arctocephalus tropicalis [Subantarctic Fur Seal] See: Arctocephalus forsteri; A. gazella; A. philippii.
Callorhinus ursinus [Northern Fur Seal]
See also: Arctocephalus townsendi; Otaria flavescens.
× Eumetopias jubatus (♂) [Northern Sea-Lion | Steller Sea-Lion] CON: northern Pacific. Ackermann (1898, p. 57) says Georg Wilhelm Steller (1709-1746), the original documenter of the principal animals of the Aleutians, reported that these seals hybridized on Bering Island, where he was shipwrecked in 1741. Recent authors have reported only copulation (Brunner 2002, p. 135). E. jubatus males are dominant over C. ursinus males. Morton 1847b (p. 276, citing Prichard 1836, p. 142) also mentions “the singular fact discovered by the traveler Steller, and mentioned by Rudolphi [1812, p. 165], that the sea-lion, Phoca jubata [=Eumetopias jubatus], of Behring’s Island, produces young with the sea-bear, P. ursina [=Callorhinus ursinus]. ‘I have no doubt of this fact,’ adds Professor Rudolphi, ‘since Pallas speaks of Steller with the greatest respect, and Telesius proved the accuracy of his observations.’” Prichard himself (p. 142), citing Steller and Kulmus (1753), says, “Steller declares, that in Behring’s Islands, sea-lions or phocæ jubatæ frequently breed with the female phocæ ursinæ or sea-bears.”
× Otaria flavescens [South American Sea-Lion] Citing Ackermann (1898), Gray (1972) lists this cross (as C. ursinus × O. byronii), but Ackermann mentions only Phoca jubata (=Eumetopias jubatus), and the site of hybridization mentioned is Bering Island, which is not in the range of O. flavescens. See: Callorhinus ursinus × Eumetopias jubatus.
× Zalophus californianus [California Sea-Lion | Galapagos Sea-Lion] CANHR. CON: British Columbia to central California, including breeding colonies at Año Nuevo and the Farallon Islands (western coast of U.S.). On San Miguel Island in 1972 and 1981, three ostensible Callorhinus pups were found with the fur extending onto the fore flipper beyond the wrist (normally diagnostic of Zalophus). Genetic testing indicated the animal found in 1972 was probably a hybrid. Jameyson et al. (1981) report an animal that was either this hybrid or Arctocephalus townsendi × Callorhinus ursinus. DeLong 1982; DeLong (cited by Goldsworthy et al. 1999, p. 262); Duffield 1999; Miller et al. 1996 (p. 472).
Eumetopias jubatus [Northern Sea-Lion | Steller Sea-Lion]
See also: Callorhinus ursinus.
× Zalophus californianus [California Sea-Lion | Galapagos Sea-Lion] NHR. CON: California (San Miguel Island). Breeding contact seems to be parapatric. Miller (1996, p. 471) says that only 11 of 34 Z. californianus females mating with an E. jubatus male survived (DeLong 1982). Most such encounters involved pre-estrous females, but two involved females that solicited or were receptive to the male. Over three years of observation, at least 84 Zalophus females died as a result of interactions with this male. Most died of suffocation or wounds to the head. The same male killed 12 Zalophus males by lying on them until they died. Miller (1996, p. 472) notes that several probable hybrids were observed. Gorodezky1995.
Otaria flavescens [South American Sea-Lion]
See also: Arctocephalus australis; Callorhinus ursinus.
× Zalophus californianus (♀) [California Sea-Lion | Galapagos Sea-Lion] CANHR. CON: northwestern South America. A male hybrid born at Frankfurt Zoo suffered a ruptured liver during delivery and died. Although two Arctocephalus pusillus males were living in the same enclosure, Kirchshofer says the sire was quite certainly O. byronii (i.e., O. flavescens). He also says that it may be that the reason that this cross had not been previously reported from zoos is that these seals are rarely kept together. Brunner (2002) discusses the skull of a probable natural hybrid (AMNH80082). Kirchshofer 1968†.
Phocarctos hookeri [New Zealand Sea-Lion] See: Arctocephalus forsteri.Zalophus californianus [California Sea-Lion | Galapagos Sea-Lion] See: Arctocephalus pusillus; A. townsendi; Callorhinus ursinus; Otaria flavescens.
By the same author: Handbook of Avian Hybrids of the World, Oxford University Press (2006).
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