Los mamíferos marinos, buzos por naturaleza.

Marine mammals are a diverse group, including 130 species. These animals have acquired, through evolution, traits that allow them to live at sea. One of the most striking features of marine mammals is that, although they have lungs, they can dive to great depths while holding their breath for extended periods. Diving allows them to meet basic needs such as feeding, mating, and can provide protection from predators. The duration and depth of the dives is associated to physiological adaptations, including increased hemoglobin and myoglobin reserves, and antioxidant defenses, that can be influenced by the size of each species. For example, sea otters can reach depths of less than 20 m, while larger marine mammals such as the sperm whale can descend up to 3000 m. This paper presents the general characteristics of marine mammals and briefly describes the morphological and physiological adaptations that allow them to dive without suffering the consequences of oxidative stress.