Anti-Predatory Strategies of

Cape Fur Seals at Seal Island

From direct observation and the data collected, Cape Fur Seals apparently reduce their vulnerability to White Sharks by:

In short, the Cape Fur Seals' main anti-predatory strategies rely on vigilance and agility

Porpoising in Cape Fur Seals

As noted previously, two basic types of porpoising have been noted at Seal Island. 

1) high porpoising is most often near (within 100 metres) the shore and is often followed by minor course changes. Therefore, this behavior may help seals get their bearings on beaching or rafting sites.

2) low porpoising is typically observed relatively far (more than 100 metres) from shore and often aborted in favor of anti-predator movements. Thus, this behavior may be a way for seals to maximize sub-surface vigilance and thereby reduce their vulnerability to White Sharks.

Curiosity in Cape Fur Seals

Cape Fur Seals are intensely curious animals, using their large, well developed eyes and sensitive mouths to investigate virtually everything in their environment.  The individual at right is clearly craning its neck to get a better look at the photographer (my lovely wife, Anne).  But when White Sharks are about, such curiosity is abandoned and all eyes search anxiously beneath the surface.  Curiosity may have killed the proverbial cat, but it probably won't snuff one of these bear-descended explorers.

Note: Although the contents of this page is drawn largely from my own observations, I would like to acknowledge that many of these seal behaviors were first pointed out to me by two very talented South African naturalists, Chris Fallows and Rob Lawrence, of African Shark Eco-Charters. Were it not for Chris's and Rob's generosity in sharing their observations, I could not have gotten a conceptual handle on what's going on at Seal Island as quickly as I did.


ReefQuest Centre for Shark Research
Text and illustrations R. Aidan Martin
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