Throwing a baby dolphin to death like a ball! How terrible is it that the killer whale has been focusing on bullying for 60 years?

On July 25, 2022, killer whale researcher Deborah Giles witnessed a severe incident of marine animal bullying .

With the rapid burst of water, several killer whales suddenly rushed towards their boat. The killer whale No. J41 and its 7-year-old son led the way, and the two killer whales swam side by side closely. In the middle of the killer whale's body, there was a young harbor porpoise , which was under the killer whale's control and could not move.

In the Salish Sea, killer whales have been playing with porpoises repeatedly | Wild Orca

Over the next 35 minutes, the five killer whales gathered together and took turns pushing the baby dolphin around like a ball until the poor little dolphin was tortured to death .

This strange bullying behavior has existed in the southern killer whale group in the northeastern Pacific Ocean for more than 60 years - why do killer whales do such excessive things to baby dolphins?

Focusing on bullying for 60 years

Although the frequency is not high, bullying porpoises and even playing with them to death is a long-standing "collective activity" among this group of killer whales. Between 1962 and 2020, 78 such incidents were recorded in the Salish Sea area on the border between Canada and the United States alone. This behavior has been passed down from generation to generation among killer whales and has become more frequent in recent years.

A mouse dolphin being pushed out of the water by a killer whale | Wild Orca

The bullied ones are usually solitary young porpoises, and the killer whales that participate in the bullying are usually 2-4, but sometimes there are as many as a dozen killer whales in a group.

Once caught, the poor dolphin will be pushed out of the water by the killer whales , slapped with their tail fins, or thrown around like a ball. The killer whales seem to have a common "rule of the game", which is to keep the dolphin above the water as much as possible - just like a group of people playing catch in a swimming pool.

Just like playing catch in a swimming pool, porpoises are tossed around by killer whales | Tuchong Creative

Bullying often has fatal consequences for dolphins due to excessive shock, drowning and trauma: in 36% of bullying incidents, the actions of killer whales resulted in the death of the dolphin in question .

Even after the victim was killed, the orcas continued to play with the porpoises over and over again , deliberately throwing them out, diving back into the sea to retrieve the bodies, and playing with them again. This vicious behavior sometimes lasted for up to five hours.

Why hurt if you don't eat it?

What is the purpose of killer whales doing this? Researcher Giles is trying to find the answer.

To be sure, this is definitely not to fill their stomachs . The southern pod of killer whales to which the bullies belong is a group that specializes in eating fish. These killer whales almost exclusively eat king salmon and have no interest in eating mammals. Moreover, in every recorded bullying incident, the killer whales have never eaten the carcasses of the victim dolphins .

Chinook salmon (Oncorhynchus tshawytscha), also known as king salmon, is a staple of southern killer whale diet | Wikipedia

Giles lists three possible motivations for the killer whales , two of which are more purposeful. Killers sometimes deliberately let go of dolphins and then catch them again, possibly practicing hunting techniques . And when reproductive female killer whales carry dolphins, they may also be performing a care behavior - but in a completely misplaced way.

The third and most likely answer is that the killer whales may not have a purpose for doing this, they are just playing . Teasing dolphins may be a popular play culture among killer whales, just like playing ball with human friends. This confusing activity may enhance the feelings and cooperation between killer whales , so that killer whales of all ages can enjoy it.

Killer whales confuse culture

Like humans, killer whales have pop culture that can spread through social learning, the most famous example of which is the salmon hat trend.

This trend also appeared in the southern killer whale group. In 1987, people first observed a female killer whale wandering around with a salmon carcass on her head, looking like she was wearing a hat . In the next 5-6 weeks, this behavior inexplicably spread rapidly among the killer whales, and all the killer whales were wearing "salmon hats" for a while . This trend broke out quickly and disappeared quickly. In the summer of the following year, people still saw killer whales wearing "salmon hats" several times, but this fashion accessory has never appeared since then.

In the summer of 1987, killer whales were wearing salmon hats | Emma Luck

In recent years, another killer whale cultural trend seems to threaten human safety.

This time, the killer whales involved were from a different group. Since July 2020, they have attacked small boats several times near the coast of Spain and Portugal, even sinking at least three ships. These killer whales always approach quietly from the stern, slamming the rudder with their heads and bodies, and even completely breaking the rudder .

Curious killer whales have created all sorts of play styles that have become popular culture — except that the people they play with may not be happy | Wikipedia

Scientists speculate that the killer whales are not trying to kill humans or seek revenge on them - they are probably just curious about the boats and want to play with them . The killer whales may have developed a taste for the rush of water from the propellers.

Although killer whales often look like bullies in the sea, scientists still emphasize that we cannot measure them with human moral vision . In an open letter in response to the killer whale collision incident, animal protection experts pointed out that when wild animals exhibit novel behaviors, humans need to keep a cool head and not punish them for "behaving wildly."

However, I still hope that at least the pop culture of killer whales hitting ships will fade away as soon as possible...

References

[1]https://www.wildorca.org/harbor-porpoise-meets-fish-eating-killer-whales/

[2]https://onlinelibrary.wiley.com/doi/full/10.1111/mms.13073

[3]https://uk.whales.org/wp-content/uploads/sites/6/2023/08/Open-letter-re-Iberian-orcas-FINAL-August2023.pdf

[4]https://www.ucdavis.edu/climate/news/why-are-killer-whales-harassing-and-killing-porpoises-without-eating-them

Author: Window Knocking Rain

Editor: Little Towel, Mai Mai

Image source: Wild Orca