Fascinating Orcas

 

Among the oceanic dolphin species, they date back eleven million years or more. Orcas are extremely social animal they are cute, knowledgeable, alert, active, and sophisticated apex predators. They have emotions, care, and love for their group members and generations, they even grieve over a deceased member just like humans, one of the incidents noted in 2018 where an orca named j35 lost her calf and carried her dead for days through the ocean. They hunt in packs like wolves and dwell in herds like elephants. They are the largest members of the dolphin family, averaging 23 to 32 feet in length and 6 tonnes in weight. They are one of the few mammals to go through menopause. They possess Bio sonar (echolocation) abilities.

image: creative commons 

Orca Brain

According to Neuroscientist Lori Marino and a team of researchers, Orca (killer whales) has the second biggest brain among all ocean mammals' weight (15 pounds). They found that orca brains are well-wired for sensing and analysing three-dimensional water environment. They possess Bio sonar (echolocation) abilities because they have evolved immersed in water which is a tremendous transmitter of sound four times faster than air, as a result, they utilize sound to see the world around them.

Cortical thickness (cerebral cortex) cognition

This portion of brain is related  with memory, consideration , dialect , thought, and awareness. Additionally, orcas have the thickest corticals. The killer whale has more cortical neurons and gray matter than any other animal, including humans. 

Gyrification

Gyrification is the number of wrinkles and folds in the cortex. Gyrification increments the amount of  cortical nerve tissue that processes information. Gyrification allows cells to be closer to each other. Due to Gyrification, it requires less time and energy to transmit neural impulses. It increases the speed of brain cell communication.GI for Orca is 5.70. This makes the orcas the most gyrified brain in the world

Brain lobes (Paralimbic system) and Amygdala

This part of the brain is related to memory and navigation. And this part of the brain is highly developed in orca. Amygdala is associated with emotional learning and long-term memories.

Orcas have the world's most elaborate insular cortex, which is connected to memory. 

The most fascinating part of the orca brain that amazes scientists is the insular cortex (insula) it is involved in consciousness and playing diverse functions linked to emotions that include compassion, empathy, perception, self-awareness, and interpersonal experience.  

Matrilineal Family Structure and Menopausal orcas

Orcas have intricated social structures with a female at the top. The young spend their whole lives with their mothers, mother prepare them for life through training. They breed primarily in the summer, and their lengthy (15 to 18 month) gestation period results in the delivery of just one calf at a time. If a mother is still alive and doesn't have any sons left, she might be observed swimming with her daughter and grandkids as well. Although adult daughters who have children of their own may temporarily distance themselves from their mothers to care for their needs, they are typically seen traveling close by. Males develop between the ages of 12 and 14, and females begin to procreate at 11 to 13 years of  age.  Because they are often larger than female orcas, male orcas are more reliant on their mother for food.

Menopause occurs in cows (female orcas) around the age of 40, or extremely unusual circumstances, 45. Male orcas live 29 years on average, to a maximum of 50 or 60 years, whereas female orcas live an average of 50 years in freedom, with some living to 80 or 90. The 1960s, grandma theory can be used to explain one of the reasons why menopause has evolved in orcas. According to this theory, grandmothers' assistance allows a younger mother to have more children and they also share their expertise and experience about how to care for themselves and their baby.

Orca habitat and what they eat

Orcas are found in every ocean of the world Orcas are primarily found in cold water due to the availability of food, though they travel in groups of 3 to 50 or more members they can cover 50 km in an hour and can even be found in tropical waters. The majority of orcas species are present in coastal water areas, polar ice caps, the north Pacific Ocean, particularly the Alaskan coast, and Baja California (Mexico). In the North Atlantic, they can be found from the waters of Newfoundland and Labrador to Iceland, Norway, and the British Isles, off the shores of Argentina, South Africa, New Zealand, and the Galapagos Islands, killer whales can be observed in the Southern Hemisphere.

There are various ecotypes of orcas, some of them are Resident orca, Southern Resident orca, and offshore orcas, and depending on where they dwell, their diets vary. However, some of the components of their diets include tuna, salmon, and seal. Depending on the availability of food and the ecology of their habitats, squids, sea lions, penguins, whales, and porpoises are among the other food sources.

How they attack their prey 

They attack in groups and are distinguished by their apparent communication and high level of group coordination. They snoop up on their victim from behind, dive beneath it, and then emerge, slicing it into pieces and sharing it. They are trained for shows despite their unique hunting methods. Namu, an orca who was kept in captivity at the Seattle Aquarium and had become completely tame, drowned when he tried to escape in 1967. Two additional orcas that are trained and kept in captivity are Shamu and Skana. In 1968, a group of killer whales was captured in British Columbia's garden bag and sold to the Vancouver Public Aquarium. one of the members named Hugo (male orca) was sold to Seaquarium Miami, Florida, and there he has shown great interest in people.