Aggressive Behavior in Marine Mammals: can’t we all just get along

Photo credit: Cathy Webster

Photo credit: Cathy Webster

Reading the article on aggressive behavior in the Encyclopedia of Marine Mammals is a serious downer. Don’t get me wrong, most of the information is standard wild animal behavior, which the author, Claudio Campagna, nicely summarizes in the introduction. “Aggressive or agonistic behaviors represent a conglomerate of social responses, including male disputes over territorial boundaries, female fights to protect an offspring, female harassment and forced copulations.”

Some of the more benign and less depressing aggressive behavior includes classic male vs. male fights over females during mating season. Not all of this behavior involves physical contact, some is resolved through “vocal signals, facial expressions, and stereotyped postures and movements, such as static open-mouthed threats, open-mouth sparring, foreflipper raise or waving, oblique staring, etc.” Oblique staring sounds like an interesting strategy, it’s not the way to win a staring contest, but maybe a less straight forward stare is more intimidating somehow, gives off a more crazy vibe.

Usually physical contact is only used as a last resort, but in some marine mammal species all out fights do take place. Male elephant seals are famous for their violent throw downs to establish a mating territory. Campagna explains that sometimes violent confrontations will last up to 30 minutes where male elephant seals throw their weight against each other and gouge each other’s face and neck with their teeth.

Whales and dolphins typically use less aggressive actions to establish dominance such as “lobtailing, tail and flipper slaps to the body of other individuals, open-mouth postures, jaw claps and vocal threat displays. ” If things get really crazy then striking each other with flukes and biting might come into play.

But now it’s time to explain some of the more disturbing aggressive behavior. The blue ribbon for most horifying goes to the pinnipeds, the suborder that includes sea lions, seals and walruses. This is possibly linked to their extreme sexual dimorphism where males are often three to five times larger than females, giving males the ability to get away with murder based on their sheer size. Some of their activities would make perfect tabloid news headlines such as “Australian sea lion abducts and abuses young pup” or “Southern elephant seal turns pup serial killer” or “Hooker sea lion males kill and eat their young.”

The story that really got me was about a crazed southern elephant seal male observed at the Patagonian colony of Peninsula Valdes where he killed and ate pups. According to the encyclopedia, “He grabbed weaned pups from the beach, dragged them to sea, kept them underwater until struggling ceased, and then tore off chunks and consumed them. The cannibal returned to the same place at least two consecutive breeding seasons and killed dozens of weanlings.”

I guess even elephant seals have a version of sociopaths lurking in their midst, the Jeffery Dahmers and John Wayne Gacys of the world aren’t soley regulated to the human race.

But despite everything I read about aggressive behavior in marine mammals and what they do to each other, nothing comes close to matching the aggression we have enacted towards them. We have managed to hunt some species to extinction, while others have died off after we destroyed their habitats and reduced their numbers through careless and selfish behavior. Many marine mammals are still struggling to recover after we reduced their numbers to deplorable lows, such as the Atlantic Right Whale, the Western Pacific Gray Whale and  the Vaquita porpoise, just to name a few. If we could learn to control our aggression and respect the rights of other species to exist, this world would be a much better place.

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