MercoPress. South Atlantic News Agency

What about a new species of penguins, the Rockaronis, a cross between Rockhopper and Macaroni

Rockhoppers are much smaller and are, in fact, the smallest penguin that nests in the Falkland Islands.

The docuseries “Secrets of the Penguins” from National Geographic captured footage of several rare penguin chicks for the very first time. Their parents are a mixed-species couple: a rockhopper mother and a macaroni penguin father. The resulting chicks, called “rockaronis” successfully hatched and appeared to be healthy and thriving so writes Jenifeer Geer for IFL Science.

The National Geographic series took place on the Falkland Islands which is also known as the penguin capital of the world, and is an excellent spot for a documentary on penguins. Falklands has five of the world’s 17 penguin species: gentoo, king, magellanic, rockhopper, and macaroni.

In the summer, the Islands are overrun with penguin families as more than one million penguins make their nests.

However in the docuseries, filmmakers captured a very rare occurrence, a pair of penguins from two distinct species formed a bond, mated, and had chicks. A macaroni penguin, (Eudyptes Chrysolophus) and a southern Rockhopper penguin (Eudyptes Chrysocome) paired up.

Filmmakers followed them beginning in courtship all the way to parenthood.

Hybrid animals are the offspring when two separate species of animals that mate. A well-known hybrid, for example, is a mule. A mule is the cross between a male donkey and a female horse. Scientists believe that hybridization plays an important role in evolution. Sometimes, hybrids end up being more resilient to their environment or having some evolutionary advantage over their parents.

National Geographic explorer, Dr. Pablo “Popi” Garcia Borboroglu, told IFL Science that hybrids between macaroni and rockhopper penguins are “extremely rare.” Despite the fact that the two species are closely related, there have been very few hybrid chicks documented. Borboroglu explained that for a hybrid to be born, “both species need to be present at the same site during the breeding season, and a mating pair must form across species lines, which is uncommon.”

Oftentimes, hybrid animals are infertile and cannot reproduce. Mules are an example of this. The only way new mules can be born is when a horse and a donkey mate. Mules cannot produce their own children. Often, a hybrid offspring is the end of the line for the mixed species.

However, when two distinct species reproduce and create a fertile offspring that is capable of having its own offspring, a new species may emerge. One reason that scientists are so excited to discover the rockaroni penguin is that rockaroni chicks are not sterile.

They are not only successfully surviving into adulthood, but they are also successfully breeding. Some have formed pairs with one of their parents’ species, while others have mated with other rockaronis. Although it may take many, many years, this is how a new species may form.

Southern rockhopper and macaroni penguins are both crested penguins. All crested penguins are black and white with yellow head feathers and red bills and eyes. Crested penguins live in the southern hemisphere on sub-Antarctic islands.

Both the Rockhopper and macaroni penguins arrive in the Falkland Islands in the summer to breed. Both species nest on the steep cliff sides and cliff tops along the coast. Also, the parents of both species take care of their young; incubating the eggs, and protecting and feeding the chicks after they are born. Rockhopper and macaroni penguins are in danger from predators at sea, including killer whales, fur seals, and leopard seals. Both species eat a diet of crustaceans and small fish.

Despite the many similarities between rockhoppers and macaroni penguins, there is one key difference. They are slightly different sizes. Macaroni penguins are about 24 to 27 inches tall and weigh around 7 to 12 pounds. Rockhoppers are much smaller and are, in fact, the smallest penguin that nests in the Falkland Islands. On average, rockhopper penguins are slightly under 19 inches tall, weighing around eight pounds.

Rockhoppers are small penguins, but their hybrid rockaroni chicks come out a bit larger. This means the baby hybrids demand more food and require more foraging trips from their smaller rockhopper parent.

Borboroglu says to IFLScience, “The rockaroni is a vivid example of how nature pushes boundaries and experiments with new possibilities. Penguins are truly an ocean of adaptation secrets, and these hybrids remind us how much we still have to learn about their biology, behavior, and evolutionary potential.”