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Characteristics of Rockhopper Penguins
Rockhopper penguins have a variety of characteristics that sets them apart from other penguins. They get the name Rockhopper penguins because they can easily hop from rock to rock compared to other penguins. Although their crests resemble other crested penguins, a trained eye can distinguish the difference even among the Rockhopper subspecies. They also have personality traits that set the apart from other penguins. Even though they have different characteristics from other penguins, they still share a few common traits that all penguins share.
Rockhopper penguins are one six crested species of penguins left in existence today. Rockhopper penguins are further classified into four subspecies. These include:
- the Northern Rockhopper (Eudyptes moseleyi)
- the Southern Rockhopper (Eudyptes chrysocome)
- the Eastern Rockhopper (Eudyptes chrysocome filholi)
- the Western Rockhopper (Eudyptes chrysocome chrysocome)
The Western Rockhopper and the Eastern Rockhopper are considered subspecies of the Southern Rockhopper.
Being a member of the crested penguin family, one of the first physical characteristic noticed is the yellow crest, or superscilium, behind their deep red eyes. The look of the crest varies between each subspecies of Rockhopper penguins. The Northern Rockhopper has large yellow and black crests that fan out. The Eastern Rockhopper has smaller yellow to white crests that lay closer to their head. The Western Rockhopper has even smaller crest that are a pale to bright yellow. The Southern Rockhopper has yellow crests that fan up but aren't a large as the Northern Rockhopper penguin.
All Rockhopper penguins have bright orange to reddish orange bills. Underneath the mandible of the Eastern Rockhopper is a pink line of fleshy skin. The rest of the subspecies has black under their mandible. They are predominantly black with a white front torso. The feathers toward the back of their head are spiked up. They have pale web feet and black leathery flippers. Some Rockhopper penguins have white stripes along their cheeks but the cheeks of juveniles are pale. The younger chicks are fluffy versions of the adults without the yellow crests.
Being a relatively small penguin, adults can reach a height of 18 to 23 inches (48 to 58 centimeters). The average Rockhopper penguin weighs in at approximately 5 pounds. However, there have been a few that have reached 11 pounds. For the most part both males and females look the same. However, the males can be larger in size than the females.
Rockhopper penguins are a grumpy lot of penguins. They have a very aggressive temperament. Rockhopper penguins will fight over practically anything. This includes food, nesting materials, mates, territory, and anything else they want. They are also very loud with their vocalizations. During breeding season, their vocalizations get even louder.
Rockhopper penguins breed in the summer months of the Southern Hemisphere starting in October. The breeding colonies are relatively small due to their aggressive disposition.They will make their nest by digging a hole and lining it with grass or choose a location among tumbled boulders of rocky shores. The females will typically lay two eggs. However, the first egg is smaller and is typically rejected by the parents. Both male and female Rockhopper penguins take turns incubating the egg until it hatches about 35 days later. They continue to care for the chick mutually until around March when the chick is ready to be self-sufficient. The average life span of a Rockhopper penguin is about ten years.
Like previously stated, Rockhopper penguins got their name because of their ability to hop from rock to rock. Their preferred habitat is the rocky shores of various islands across the Southern Indian Ocean, the South Atlantic Ocean, and the Southern Pacific Ocean.
The Northern Rockhopper penguins prefer the islands in the South Atlantic Ocean such as Gough Island and the Tristan da Cunha. They also prefer the islands of Indian Ocean like Amsterdam Island and St. Paul Island.
The Eastern Rockhopper penguins enjoy spending their time in the Indo-Pacific islands of Prince Edward Island, Heard Island, Macquarie Island, Campbell Island, Antipodes Islands, and many others in the region.
The Western Rockhopper penguins prefer the southern tip of South America and the islands off the coast. They also prefer the waters surrounding the islands in the Indian Ocean and the western Pacific Ocean just like other Rockhopper penguins.
The Southern Rockhopper penguins can be found in the Faulkland Islands off the coast of Argentina and Chile as well as the islands that other Rockhopper penguins like to congregate in the Indian Ocean.
Unfortunately, their decline in habitat has placed them on the International Union for Conservation of Nature (IUCN) list as being a vulnerable species because of their decreased population. Because Rockhopper penguins are opportunistic feeders, dining on small fish, squid, and crustaceans, their habitat has become polluted with human waste and debris. This causes their food supply to either diminish or become contaminated; making the penguins more vulnerable to death and disease. Conservation efforts are being done to try to increase the Rockhopper population but since they are so aggressive, this makes it difficult on scientists to study them much less breed them.