Members of the extant genus, Spheniscus, are known as the banded penguins, because of the band of black coloration that runs around their bodies. The genus name literally means "wedge-shaped". The four extant species are similar in color pattern and are known as "jackass" penguins because they emit loud calls to locate each other that resemble the bray of a donkey (Stefoff, 2005).
A common coloration theme unites the extant species such as, distinct spots on their abdomens, a small vertical stripe upon their back and a small patch of lightly feathered or nude patch of skin around its eyes that has a pink or whitish coloration (Stefoff, 2005).
The genus Spheniscus, both extant and extinct, is not found anywhere along the Antarctic coasts. All but one of the extant species of Spheniscus inhabit temperate climates, which include South Africaand the southern coastal areas of Argentina and Chile. The Galápagos penguin (Spheniscus meniculus) is found on along the coasts of theGalapagos Islands and inhabits one of the most northern extents of the globe occupied by any penguin species (Stefoff, 2005).
All species of penguin within the genus Spheniscus raise their young in burrows (Stefoff, 2005).
The genus Spheniscus (banded penguins) is comprised today of four extant species: Magellanic penguin (Spheniscus magellanicus), Humboldt penguin (Spheniscus humboldti), Galápagos penguin (Spheniscus mendiculus) and the African penguin, black-footed or jackass penguin (Spheniscus demersus) (Stefoff, 2005).
The genus Spheniscus (banded penguins) also presently contains four known extinct species, which include three from the Late Miocene to the Early Pliocene (3.6 -11.6 Ma) of the central Andean coast (Spheniscus chilensis, Spheniscus megaramphus, Spheniscus urbinai) and the oldest known member of the genus is from the Middle to Late Miocene (11–13 Ma) of Cerro La Bruja, Peru (Spheniscus muizoni) (Gohlich, 2007; Ksepka & Clarke, 2010).
Spheniscus demursus is a fairly accurate representative for the genus, Spheniscus. Adults of the species stand around 45 cm tall and weigh an average of 3.1 kg (Cooper, 1977; Stefoff, 2005).
Researchers analyzed skeletal remains and estimated body mass for all fossil penguins. The study found that fossil species ranged from 3 kg to 81 kg in total mass. The largest fossil species of penguin was approximately 2.5 times as massive as the largest extant spheniscid. The findings show that members of Spheniscus are small-sized penguins in both extant and extinct forms (Livezey, 1989).
All extant members of the genus have coloration that serves as camouflage, with a white stomach to match the bright surface of the ocean (to fool oceanic predators from below) and a black coloration on their back that serves disguise them in the water from aerial predators. A common coloration theme unites the extant species such as, distinct spots on their abdomens, a small vertical stripe upon their black and a small patch of lightly feathered or nude patch of skin around its eyes that has a pink or whitish coloration (Cooper, 1977; Stefoff, 2005).
Compared to other genera within the spheniscids, the genus Spheniscusis moderately dimorphic, with size differences between the sexes (Livezey, 1989).
Spheniscus live between 10 to 27 years in the wild. Extinct members of the genus most likely fell within those natural lifespans (Crawford et al., 2001; Stefoff, 2005).
Members of the genus Spheniscus are coastal-dwelling predators and prey on small shoaling fish, such as anchovies (Engraulis capensis) and sardines (Sardinops sagax). Various crustaceans and cephalopods are also known to regularly fall prey to the banded penguin (Cunningham et al., 2008).
Natural predators of the genus Spheniscus include seals, feral cats, genets, leopards, mongooses and toothed whales. Eggs and chicks are also preyed upon by gulls and ibises. They also must compete with breeding space with many pinniped (e.g., seals) species (Crawford, et al., 2001; Randall and Randall, 1990; Stefoff, 2005).
Members of the genus Spheniscus are predators of small shoaling fish, including anchovies (Engraulis capensis) and sardines (Sardinops sagax). Various crustaceans and cephalopods are also known to regularly fall prey to the banded penguin.
A recent study has shown thatSpheniscusdemersus has a functioning sense of smell that assists them in finding and locking onto their specific prey items. This sensory aptitude was, until recently, unknown and significantly increases what we know about their foraging efficiency (Cunningham et al., 2008).
Extant members of the genus Spheniscus are noisy. African penguins (Spheniscus demersus) are also known by the common name "jackass penguins" because of the loud donkey-like sounds that they produce. The noise is for the distinct purpose of communication, and research has shown that there are three types of calls, the bray, the yell, and the haw. Each call is intended to communicate or serve a specific social purpose, to make contact, defend territory or attract mates, respectively. Spheniscus is a very social genus (Frost, et al., 2009; Thumser & Ficken, 1998).
