Buzz
According to scientists, if a mother killer whale gives birth to a male, it could be the last time they reproduce.
In a study conducted by the Center for Whale Research (CWR) in Harbor, Washington, USA, published in the journal Current Biology, male killer whales matured living along the Pacific coast of North America exhibit a special bond with their mothers.
The research found that a subset of non-migratory killer whales, residing permanently off the coast of the North Pacific, tends to exhibit bias towards their sons even after they have matured. The CWR study shows that similar behaviors are not displayed towards the daughters of these killer whales.
However, what has been observed is not just parental favoritism. According to the center's findings, there seems to be a certain evolutionary advantage for mother killer whales to provide extra care for their sons. CWR's research director, Michael Weiss, states: 'For over a decade, we have known that mature male killer whales still rely on their mothers for survival.'
Non-migratory killer whales in the North Pacific's West Bering Sea often feed on chinook salmon, and what CWR researchers discovered is that mother whales only consume half of the fish they catch.
Meanwhile, their sons tend to follow behind their mothers to eat the leftover portion. This study was conducted across multiple generations of killer whales in the North Pacific region, and further research is needed to determine if these behaviors occur in other killer whale populations.
According to CWR's research director, Michael Weiss, this is the first sign that an animal species is making long-term investments in the health and happiness of its offspring. Weiss adds, 'Our previous research has shown that in killer whales, sons have a higher chance of survival with their mothers by their side.'
Researchers aim to investigate whether this additional assistance involves sacrificing anything, and the answer is undoubtedly yes. Weiss notes, 'Mother killer whales will have to pay a steep price in terms of future reproductive capabilities to ensure the survival of their sons.'
What CWR's study concludes is a trade-off for mother killer whales when they give birth to males – they won't have the ability to reproduce again. This is believed to be because mother killer whales do not consume enough nutrients for successful reproduction – mother whales share half of what they catch with their matured sons.
However, what mother killer whales achieve in doing so is the potential for their sons to become reproductively dominant in the community.
Evidence indicates a coordinated effort between mature male killer whales and their mothers, and in some killer whale populations, grandmothers play a crucial role in social structure. Regarding this, Professor Darren Croft of the University of Exeter, a participant in the study, states: 'If a mother killer whale can make its son a dominant male in the community, then subsequent generations in neighboring pods will be its descendants.'
A study in 2004 revealed that the decoded structure of the killer whale's brain surprisingly resembles that of the human brain - not only with highly folded cortex but also with similar brain regions responsible for perception and emotion, showcasing their remarkable intelligence.
Furthermore, the level of affinity of this animal species with humans even makes people forget its image as the 'underwater menace.'
In the wild, there has never been any recorded incident of killer whales attacking humans; in fact, they have been known to assist those who fall into the water. Even when fishing boats capture killer whale calves, the mother killer whales only vocalize distress instead of retaliating.
