Not much is known of the roles of southern elephant seals while they are at sea. However, they are known to be important to their ecosystem as predators of fish, sharks, squid, crabs, and shrimp and as prey for large sharks, Orcinus orca, and Hydrurga leptonyx. Another important role they play in the ecosystem is as a host for many kinds of parasites. Some of the known parasites include cestoda, acanthocephalans, and the louse Lepidophthirus macrorhini. ("Elephant Seal", 2002; "Elephant Seals", 1983; "Southern Elephant Seal", 2003; Anderson, 2003; Crown, 1997; Gaskin, 1972; Nichols et al., 2003; Seal Conservation Society, 2001; Slip and Clippingdale, 2002)
- Bradshaw, C., M. Hindell, N. Best, K. Phillips, G. Wilson, P. Nichols. 2003. You are what you eat: Describing the foraging ecology of southern elephant seals using blubber fatty acids. Proceedings of the Royal Society of London, 270: 1283-1292.
- Gaskin, D. 1972. Whales Dolphins and Seals. London: heinemann Educational Books.