Icadyptes

Icadyptes is a group of giant aquatic birds that once existed in the South American tropics during the Late Eocene. They’re members of the Sphenisciformes family, meaning they are modern penguins’ ancestors. Expectedly, they were significantly larger and lived in completely different environments compared to present-day penguins. Only one species, Icadyptes salasi, has been identified so far.

Description and Size

The genus name is formed from the words “Ica,” which is another name for the Peruvian region where fossils of the species were first discovered, and “dyptes,” which is the Greek word for “diver.” The full interpretation of this name means “diving bird found in Peru.” The specific name “salasi” refers to renowned Peruvian paleontologist Salas Gismondi.

Icadyptes salasi is one of the largest species of penguins to have ever existed. In fact, it is the third largest penguin known to man. The ancient penguin would have been about the same size as a regular small human being. It was about 5 feet (1.5 meters) tall, and its weight fell within the range of 110–176 pounds. 

Another unique thing about the species was its abnormally long beak that resembles the spearlike heron’s beak (a species of long-beaked, long-legged, and long-necked birds). The Icadyptes beak was almost eight inches long. The beak also had an unusual texture with a matrix of shallow grooves, which were probably blood vessels. Scientists believe the distinct, long, pointed beak is a common characteristic of prehistoric penguins.

Despite their large sizes, Icadyptes salasi had a relatively small head. Studies of their skeleton show that this penguin probably had a streamlined body that was adapted for diving. Icadyptes salasi wings were not as paddle-like as that of their living relatives. The bones were stronger than those of flying birds, but they could not fly, too, just like the present-day versions. 

Diet—What Did Icadyptes Eat?

The giant penguin fed on fish from the rich tropical waters in its native habitat. It would dive into the waters along the coast of South America in search of prey. On sighting suitable prey, it did not capture it in between its jaws like most birds. Instead, scientists think it speared fishes with its long beak.

Habitat—When and Where Icadyptes Lived

Icadyptes lived in the warmer latitudes near the equator, unlike present-day Sphenisciformes. The planet’s temperature at the time was at its warmest, and ice was not yet formed around the poles at the time. The African and Galapagos penguins are the only existing penguins that flourish under such warm conditions.

Icadyptes lived in Peru when the climate was much warmer than what we have today. This has led to the conclusion that penguins had already been accustomed to warm climates 30 million years earlier than previous speculations. 

Researchers had first believed that the evolution of penguins took place in the pole region of Antarctica and New Zealand before they moved toward the equator some million years ago. The discovery of fossils in more recent times led to a reevaluation of how the penguins might have evolved. 

Threats and Predators

The greatest threat to the Icadyptes was the change in the climate. The temperature of the earth greatly became cooler. This destroyed the majority of plant life and destabilized many local ecosystems. Over time, the population of fish in the ocean would have declined as well. Since the giant penguins needed a significantly large amount of food to thrive, they could not keep up with the dwindling food supply. Experts think the emergence of marine mammals would have also been a major threat to the struggling penguin population. 

Discoveries and Fossils—Where Icadyptes was Found

A team of scientists found the first fossilized remains of Icadyptes in the southern coastal desert of Peru. The remains, dated to be about 36 million years old, were discovered in the Otuma Formation. The rock is a marine deposit in the Pisco Basin. 

The skeleton of penguins is very solid, unlike the hollow bones of normal birds, such as pigeons. This makes them resistant to destruction. Hence, the bones were preserved in relatively good condition. Fossils of the Icadyptes salasi were so well preserved that the skeleton of the wings was almost complete. This makes it one of the most complete penguin fossils ever found. Hence, it gave scientists deeper insights into the biology and anatomy of the Icadyptes species.

One major anatomical difference that could be observed in this penguin was the shape of their beaks. Scientists have known for a long time that the stubby bill found in most living penguin species was an adaptation developed much later. Pieces of penguin skulls had been found in the past, which showed that prehistoric penguins had long and strongly built beaks. However, the Icadyptes provides the first complete evidence of a spear-beaked penguin. 

The Icadyptes fossil was found alongside the remains of Perudyptes devriesi (another ancient Eocene species) and three other undescribed species. All the species seemed to have stayed within the tropics instead of the colder latitudes like most of today’s penguins. 

Extinction—When Did Icadyptes Die Out?

The species became extinct towards the end of the Eocene Epoch (about 35 million years ago). Drastic climate change caused by a drop in temperature led to the loss of a lot of marine life at the time. The Icadyptes, which thrived on a piscivore diet, also suffered the consequences. Growing competition for food may have also contributed to their obliteration. Fossil studies indicated that marine carnivorous mammals became even more diverse around the same period as the giant penguins declined. 

Similar Animals to the Icadyptes

• African penguins — They are also referred to as Cape penguins or South African penguins. They are flightless birds and are natives of the Southern edge of Africa. They weigh 4.9-7.7 pounds and are around 24-28 inches tall. There are pink skin patches around their eyes, and their body is spotted. 
• Emperor penguin — The Emperor Penguin is native to Antarctica. It is also the only penguin species that breed during the winter in Antarctica. It is the largest and heaviest penguin still in existence. It is about four feet (1.3 meters) tall, and its weight ranges from 55–100 pounds. 
• Galapagos penguin — The species lives on the Galapagos Islands in Ecuador. They are the only modern penguin species living near the equator. Others prefer a cooler climate. The Galapagos penguin is considered the second smallest penguin to have ever lived. They have special mechanisms to keep them cool in their habitats. 

Related Animals 

• Emperor Penguin
• Galapagos Penguin
• African Penguin