Cape fur seals, sharks, kelp gulls, sacred ibises, mongooses, genets, leopards, and even feral cats and dogs prey on African penguins and their eggs.
Natural threats of the African penguin include competition with Afro-Australian fur seals (Arctocephalus pusillus.) The seals compete with penguins for food, displace them from breeding sites and impose significant mortality at some colonies.
African penguins also face predation of eggs and chicks by avian predators such as kelp gulls (Larus dominicanus) and African sacred ibises (Threskiornis aethiopicus), while natural terrestrial predators, such as yellow mongooses (Cynictis penicillata), cape genets (Genetta tigrina), caracals (Caracal caracal), and leopards (Panthera pardus) are also present at mainland colonies. In the water, African penguins need to fear sharks looking to take birds at sea.
Feral cats and dogs are also present along the coastlines and mainlands of Southern African and have posed a problem with some African penguin colonies.
Sources: (BirdLife International, 2016; Crawford, David, Williams, & Dyer, 1989; Crawford, et al., 2001; Makhado, Crawford, Waller, & Underhill, 2013; Pearce, 2011; Pichegru, 2013; Randall and Randall, 1990; Stefoff, 2005; Underhill, et al., 2006; Weller, et al., 2014, 2016)