Adaptation.
Behavior characteristic, body structure or capability of a species produced over millions of years of evolution and developed to increase the chances of survival and reproduction. The penguin flippers are adaptations that help them swim and look for their food in the sea.

Hatching.
Breaking the egg shell, which allows the chicks to get out of it.

Spheniciform.
A Bird that belongs to the order Sphenisciformes. Penguins are Sphenisciformes.

Incubation.
An activity that consists of keeping the eggs warm and safe from laying in the nest until hatching, while the embryos develop. The incubation period varies by species.

Convergent Evolution.
It is an evolutionary process that occurs in distantly related species, creating similar structures but through independent developments. For example, penguins and razorbills have similar plumage layers, the product of convergent evolution, but they are not genetically related animals; However, they may have shared a common ancestor.

Sexual dimorphism.
Set of anatomical variations or differences (size, weight, color, shape, etc.) between males and females of the same species.

Philopatry.
It is the habit or tendency of some animal species to remain all their life in the place where they were born or to return there periodically, to reproduce or lay eggs.

Fossil.
It is called thus the remains, impressions or traces of a species of organism that lived in past geological eras.

Guano.
It is the excrement of certain birds, like penguins and cormorants, as well as of some mammals. This word has its origin in the Quechua language.

Habitat.
It is the living space where a species finds all the resources it needs to survive: water, food, and shelter. Likewise, it must possess a suitable climate for enduring. The habitat of an animal allows it to maximize its biological efficiency and reproduce successfully.

Krill.
Small crustacean slightly similar to shrimp, found in the cold waters of the Atlantic, Antarctic and Pacific oceans. It usually feeds on plankton, and in turn, serves as food for numerous species such as some bearded whales and penguins.

Melanin.
A natural pigment found in the body of many living beings, produced by cells called melanocytes, which gives them dark coloration in the skin or feathers.

Monogamy.
A mating system consisting of having a single partner throughout a reproductive season or an entire life. It is the opposite of polygamy, in which individuals of a species mate with more than one individual of the opposite sex.

Regurgitate.
Action to expel solid or liquid matter that comes from the stomach or the esophagus.

Thermoregulation.
It is the ability to automatically regulate the temperature to keep it stable and within certain limits that allow maintaining the organism in optimal conditions.