Sunday 16 November 2008

Jackass & Galapagos Penguins

Here are the penultimate penguins: Jackass penguin (Spheniscus demersus) and Galapagos penguin (S. mendiculus). The Jackass penguin is also known as the black-footed penguin, or the African penguin. Penguins, in Africa? Are you bonkers? What’s next, polar bears in the Sahara? No, don’t be silly. There is a cold-water current responsible for this bird’s distribution, the Benguela Current, bringing nutrient-rich cold water from the Southern Ocean to the south-west Atlantic via South Africa and Namibia.

The Galapagos penguin is the most northerly species of penguin, it is even found at the Equator! This is even more crazy than the idea of an African penguin. Why would a classically cold-climate bird be found in the Tropics? The answer also lies in the ocean currents: cold waters from the Antarctic flow up the Pacific coast of South America towards the Galapagos Islands, bringing nutrients. This current, the so-called Humboldt Current, also gives its name to another species of penguin from the coast of South America, covered in the next post. As a result of warmer air temperatures, the penguins of Galapagos, south Africa and other places are smaller. Other than the little blue penguin of Australia and New Zealand, the four penguins of the genus Spheniscus are the smallest.

Jackass penguin
Spheniscus demersus (Linnaeus, 1758)

Adult Jackass penguin (Spheniscus demersus)

Distribution: southern Africa from 24o38’S to 33o50’S; vagrant to other parts of Africa.

Size: 70 cm (27½”); males and females weigh 2.4-4.2 kg (5 lb 5 oz – 9 lb 9 oz), with males larger than females.

Habitat: breeds on Benguela Current influenced coasts, in burrows with suitable substrate or using bushes and boulders as shelter.

Diet: small fish, cephalopods (such as squid), crustaceans and polychaete worms.

Etymology: Spheniscus = “little wedge” in Greek; demersus = “diving” in Latin.

Immature Jackass penguin (Spheniscus demersus)

Galapagos penguin
Spheniscus mendiculus Sundevall, 1871

Adult Galapagos penguin (Spheniscus mendiculus)

Distribution: restricted to the Galapagos Islands; breeds on Fernandina and Isabela, and maybe on Bartholomew and Santiago Islands; non-breeding range extends to other islands of the archipelago.

Size: 53 cm (21”); the smallest Spheniscus penguin; males weigh 1.7-2.6 kg (3 lb 11 oz – 5 lb 11 oz); females weigh 1.7-2.5 kg (3 lb 11 oz – 5½ lb).

Habitat: low-lying volcanic coastal desert.

Diet: fish (such as mullet and sardine) and crustaceans (such as krill).

Etymology: Spheniscus = as S. demersus; mendiculus = “little beggar” in Latin.

Immature Galapagos penguin (Spheniscus mendiculus)

Oh, and while we're on the topic of Galapagos... if you're in London for the next few months, make sure you visit the new exhibition at the Natural History Museum, Darwin: The Big Idea. There is a stuffed Galapagos penguin there, as well as numerous other animals and plants from the archipelago, and two live animals: Charlie the green iguana (Iguana iguana) and Sumo the Argentine horned frog (Ceratophrys ornata). Not to mention a lot of original material from Charles Robert Darwin's epic voyage that first sparked his theory of evolution by natural selection.

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