For decades, fish-eating killer whales in the Pacific Northwest have been observed harassing and even killing porpoises without consuming them—a perplexing behavior that has long intrigued scientists.

A study published today in Marine Mammal Science, co-led by Deborah Giles of Wild Orca and Sarah Teman of the SeaDoc Society, a program of the UC Davis School of Veterinary Medicine, looked at more than 60 years of recorded interactions between Southern Resident killer whales and porpoises in the Salish Sea to better understand why they exhibit this behavior.

Southern Resident killer whales are an endangered population, numbering only 75 individuals. Their survival is intimately tied to the fortunes of Chinook salmon — also an endangered species. Without enough Chinook salmon, these whales are in danger of extinction.

“I am frequently asked, why don’t the Southern Residents just eat seals or porpoises instead?” said Giles. “It’s because fish-eating killer whales have a completely different ecology and culture from orcas that eat marine mammals — even though the two populations live in the same waters. So we must conclude that their interactions with porpoises serve a different purpose, but this purpose has only been speculation until now.”

Three plausible explanations

While scientists have recorded instances of Southern Resident killer whales engaging in porpoise harassment as early as 1962, reasons for this behavior have long remained a mystery. Giles, Teman, and a team of collaborators analyzed 78 documented incidents of porpoise harassment from 1962 to 2020. The study suggests three plausible explanations:

• Social play: Porpoise harassment may be a form of social play for killer whales. Like many intelligent species, these whales sometimes engage in playful activities to bond, communicate, or simply enjoy themselves. This behavior might benefit group coordination and teamwork.
• Hunting practice: Another hypothesis suggests that porpoise harassment might hone their salmon-hunting skills. Southern Resident killer whales could view porpoises as moving targets to practice their hunting techniques, even if they do not intend to consume them.
• Mismothering behavior: This theory suggests that the whales may be attempting to provide care for porpoises they perceive as weaker or ill–a manifestation of their natural inclination to assist others in their group. Females have been witnessed carrying their deceased calves and have been seen similarly carrying porpoises.

“Mismothering behavior — also known as ‘displaced epimeletic behavior’ to scientists— might be due to their limited opportunities to care for young,” Giles explained. “Our research has shown that due to malnutrition, nearly 70% of Southern Resident killer whale pregnancies have resulted in miscarriages or calves that died right away after birth.”

Salmon specialists

Despite these intriguing insights, Giles, Teman, and their collaborators acknowledge that the exact reason behind porpoise harassment may never be fully understood. What is clear, however, is that porpoises are not a part of the Southern Resident killer whale diet. Southern Resident killer whale diets are highly specialized for salmon, making the idea of eating porpoises highly unlikely.

“Killer whales are incredibly complex and intelligent animals. We found that porpoise-harassing behavior has been passed on through generations and across social groupings. It’s an amazing example of killer whale culture,” Teman says. “Still, we don’t expect the Southern Resident killer whales to start eating porpoises. The culture of eating salmon is deeply ingrained in Southern Resident society. These whales need healthy salmon populations to survive.”

This research underscores the importance of conserving salmon populations in the Salish Sea and throughout the whales’ entire range. Maintaining an adequate supply of salmon is vital for the survival and well-being of Southern Resident killer whales and the overall health of the Salish Sea ecosystem.

Affinity for play

This study comes at a time when a separate population of killer whales on the Iberian Peninsula has drawn international headlines for interacting with, and on three occasions, sinking boats off the coast of Portugal and Spain. Ultimately, the Southern Resident killer whales and the Iberian Peninsula orcas are two different populations with distinct cultures. One thing the two might have in common is their affinity for play behavior.

The study was funded by Wild Orca and SeaDoc Society. Additional partners include the University of Exeter, Fisheries and Oceans Canada, Orca Behavior Institute, National Oceanic and Atmospheric Administration, Cascadia Research, The Whale Museum, Center for Whale Research, Ocean Research College Academy (ORCA) at Everett Community College, Bay Cetology, North Gulf Oceanic Society, George Mason University, and Marine-Med.

September 28, 2023 – Recently popularized utility terrain vehicles (UTVs) with “side-by-side” passenger seating are associated with higher rates of severe hand injuries when compared to traditional all-terrain vehicles (ATVs), reports a study in the October issue of Plastic and Reconstructive Surgery®, the official medical journal of the American Society of Plastic Surgeons (ASPS). The journal is published in the Lippincott portfolio by Wolters Kluwer. 

“Our study finds much higher rates of mutilating hand injuries and amputations associated with side-by-side UTVs, compared to ATVs,” comments ASPS Member Surgeon Shaun D. Mendenhall, MD, of Perelman School of Medicine at the University of Pennsylvania, Philadelphia who performed the study along with colleagues at his prior institution, the University of Utah. “We believe hand surgeons can play a key role in increasing awareness and prevention of ATV-related hand injuries.” 

Higher rates of mutilating hand injuries and amputations with UTVs 

Side-by-side UTVs are an increasingly popular category of off-road vehicles, used for outdoor adventure and work. Utility terrain vehicles have side-by-side passenger seating, safety belts, and a rollover protection system (ROPS). These design features provide a false illusion that UTVs are safer than ATVs, which have straddle seating, no safety belt, and no ROPS.  

In recent years, the hand surgery center at the University of Utah, situated in the Mountain West, has seen more cases of upper extremity (hand, arm, and shoulder) injuries in UTV riders – more so than in ATV riders. Although enclosed UTVs may prevent riders from being ejected, those whose arms are extended outside the vehicle during a collision or rollover event may sustain serious hand and arm injuries.  

Dr. Mendenhall and colleagues compared the rates, patterns, and severity of upper extremity injuries in ATV versus side-by-side UTV riders. From 2010 to 2021, the authors’ department treated 87 individuals who were injured in ATV accidents and 67 individuals who were injured in UTV accidents.  

Although injury location along the upper extremity were similar between groups, UTV riders had significantly higher rates of mutilating injuries. Mutilating injuries were defined as traumas that caused irreparable damage to the appearance and function of the hand. Overall, UTV riders had three times the amount of mutilating injuries compared to ATV riders (64% versus 22%) and nearly ten times the amount of amputations (30% versus 3%). 

Due to the severe nature of these injuries, patients in the UTV group spent more time in the hospital (5 versus 2.5 days) and underwent twice as many surgeries (2.4 versus 1.1 surgeries) compared to patients in the ATV group. After adjustment for other factors, UTVs were the only independent risk factor for these outcomes. 

Call for steps to reduce hand injury risks in ATVs and UTVs 

Injuries occurred in UTV riders of all ages and in those who were the drivers and passengers of accidents. Seatbelt use was unrelated to the risk of injury or amputations in UTV riders. There were insufficient data on the use of other protective equipment, such as mesh windows or doors and wrist straps.  

As they grow in popularity, side-by-side UTVs may be “a new source of mutilating hand injuries,” according to the authors. The injury patterns are consistent with those previously described in riders who extend their hands outside the vehicle during a rollover incident, with “a high likelihood of having their hand crushed between the ROPS and the ground.” 

“Hand surgeons are in a unique position to serve as forerunners for increasing public awareness and promoting patient advocacy,” Dr. Mendenhall and coauthors conclude. “Working alongside manufacturers in community education initiatives and product development are ways we can promote safe rider habits and prevent upper extremity trauma.” 

Read Article [ A New Source of Mutilating Hand Injuries: The Side-by-Side Utility Terrain Vehicle ] 

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About Plastic and Reconstructive Surgery 

For over 75 years, Plastic and Reconstructive Surgery® (http://www.prsjournal.com/) has been the one consistently excellent reference for every specialist who uses plastic surgery techniques or works in conjunction with a plastic surgeon. The official journal of the American Society of Plastic Surgeons, Plastic and Reconstructive Surgery® brings subscribers up-to-the-minute reports on the latest techniques and follow-up for all areas of plastic and reconstructive surgery, including breast reconstruction, experimental studies, maxillofacial reconstruction, hand and microsurgery, burn repair and cosmetic surgery, as well as news on medico-legal issues. 

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The American Society of Plastic Surgeons is the largest organization of board-certified plastic surgeons in the world. Representing more than 7,000 physician members, the society is recognized as a leading authority and information source on cosmetic and reconstructive plastic surgery. ASPS comprises more than 94 percent of all board-certified plastic surgeons in the United States. Founded in 1931, the society represents physicians certified by The American Board of Plastic Surgery or The Royal College of Physicians and Surgeons of Canada. 

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