Orcas

    Orcas, also known as Orcinus Orca, are carnivorous mammals that can weigh up to 6 tons, are 23 to 32 feet long, and can live from 50 to 80 years old. An orca is the largest dolphin and is the world’s most powerful predator with teeth that measure up to 4 inches. Orcas can swim up to 40 miles a day and dive 100 to 500 feet several times a day. 

    They travel in pods, family groups that consist of up to 40 orcas. Each pod has its own distinctive noises that its members can recognize even from a long distance. Orcas are known to be smart and social, an example of this is when pods hunt using cooperative techniques that liken them to wolf packs. An orca uses echolocation to hunt and communicate and eat fish, penguins, and marina animals. While orcas are generalized eaters, once they’ve learned what their family eats, it’s unlikely that they’ll change their diets after. Orcas can be found from the polar regions all the way to the equator, but most often frequent cold, coastal waters. 

       Orcas are also referred to as killer whales due to ancient sailors’ observations of pods hunting and eating bigger whales. They first called orcas “asesina ballenas”, or whale killer, a term that was flipped to killer whale later on in time. Orcinus Orca reflects the sailors’ observations with Orcinus meaning ‘of the kingdom of the dead’ and orca referring to some kind of whale. 

    While humans have a breathing reflex that lets us automatically breathe while sleeping, orcas do not. To combat their manual breathing problems, orcas only allow one half of their brain to fall asleep while the other half makes sure that the orca continues breathing and looks out for danger. Orcas close only one eye when sleeping; the right eye will be closed while the left side of the brain is sleeping, and vice versa. This kind of sleep is known as unihemispheric sleep, only one half of the brain sleeps at a time. Periodically, orcas will change which side of their brain sleeps so that they can get rest without ever falling unconscious and suffocating or drowning.

Sources: nationalgeographic.com, us.whales.org