Galapagos Penguin
Tagged: animal, animals, bird, cat, dog, fish, mammalSpheniscus mendiculus
The only species of penguin to live on the Equator, the portly Galapagos penguin breeds on at least five of the Galapagos Islands. Because of its restricted range and very small population, a sharp decline in numbers is particularly disturbing. Penguins are normally associated with cold habitats in and around Antarctica, although several species have ranges that include warmer climates. The Humboldt penguin, for instance, breeds in coastal Chile and Peru. However, the Galapagos penguin a close relative of the Humboldt is the only species that lives entirely within the tropics, on at least five islands of the Galapagos group. Life at such latitudes is challenging for the birds, since their insulating plumage, underlying fat, and specialized blood heat exchange-all adaptations for surviving in very cold water-make it difficult for them to cope with the tropical heat when on land. Temperatures in the Galapagos islands can rise to more than 104°F (40°C). Adaptations to Heat In order to survive the heat, the Galapagos penguin has various anatomical and behavioral adaptations. It is one of the smallest penguin species, and the smaller an animal, the greater its surface area relative to its total size. Consequently, the Galapagos penguin has a large surface area from which to dissipate (lose) heat when on land. Heat loss is made easier by its having shorter feathers than any other species of penguin. When ashore, the adults seek shade. They lose more heat by increasing the blood flow to their flippers, feet, and bare facial patches. The flippers are proportionately larger than those of cold-climate penguins, increasing the area where heat exchange can take place. The animals’ blood supply can also bypass the heat-transfer system that helps maintain their body temperature in cold water. Galapagos penguins often breed in rock crevices and caves, such as lava tubes (natural tunnels in lava flows) that shade the birds and their chicks from the sun.
Major Threats
The Galapagos penguin depends directly on the surrounding ocean for its survival. The Cromwell Current, an upwelling of cool, nutrient rich water, maintains the fish stocks that the penguins rely on for food. The current is susceptible to a periodic climatic event called the El Nino Southern Oscillation (ENSO). Records show that a population of 3,400 penguins declined by 77 percent between 1982 and 1983-an ENSO year that adversely affected the Cromwell Current, reducing fish stocks and causing thousands of birds to starve. It is likely that more females than males died, which would have slowed the recovery of the population. Another ENSO event in 1997 caused a further decline of 66 percent. Galapagos penguins are known to be slow breeders, the birth rate averaging out at only 1.3 chicks per year. In ENSO years the entire population can fail to breed at all. The animals also have a restricted breeding range, with about 95 percent nesting on just two islands.
Chicks and eggs are vulnerable to natural predators such as rice rats, snakes, and crabs. More serious threats are posed by introduced predators, including feral dogs, cats, and brown and black rats, which kill adults and chicks. A tenfold increase in the permanent human population of the Galapagos in the last 40 years has led to disturbance of breeding sites and an expansion of coastal fisheries. Penguins are caught in nets and suffer from competition for fish stocks. Tourism adds to disruption; visitors come to look at the birds. To ensure the continued survival of the Galapagos penguin, controls on fisheries, oil spills, human disturbance, and the introduction of mammalian predators are urgently required, as are scientific studies of the penguins to help increase their breeding success rate. Most importantly, we need to cut fossil fuel emissions to reduce global warming, which is likely to increase ENSO events.
Galapagos penguins
feed on the rich fuh stocks around the Galapagos Islands. The small, dapper bird has large flippers and feet that hey it dissipate body heat.
Galapagos penguin Spheniscus mendiculus
- Family: Spheniscidae
- World population: Fluctuates greatly; currently estimated at 1,200 individuals
- Distribution: Galapagos Islands, Ecuador
- Habitat: Breeds on low-lying areas of coastal, volcanic desert, rarely more than 55 yards (50 rm inland; feeds around upwellings of cool, nutrient rich inshore waters
- Diet: Schools of ocean fish, including sardines and mullet. Possibly crustaceans
- Breeding: Breeds at any time, in small colonies or singly, when food supply is adequate; nests in lava tubes, rock crevices, or caves, at least partly shaded from the sun; 2 white eggs laid per breeding attempt; pair shares incubation that lasts 5-6 weeks; young leave nest at 8.5-9 weeks
- Size: Length: 19-21 in (48-53 cm); height: 14 in (35 cm). Weight: average 3.8-5.7 lb (1.7-2.6 kg)
- Form: Small with black head; white stripes on face; black to brownish back and tail; chin and underparts white; variable pattern of black spots and irregular black bands on breast; flippers brown-black above, white below; male more boldly marked. Juveniles have grayish upperparts and lack distinctive face pattern
- Related endangered species: Nine other penguin species are threatened, including African penguin (Spheniscus demersus); Humboldt penguin (S. humboldti); erect-crested penguin (Eudyptes sdaten), Snares penguin (E. robustus)
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