avoid predatorsis one of the most of import job for many members of the animal public . Even ocean monster like baleen whales have something to fear from killer whales , theironly known natural predators . To avoid coming across killer whales , new research has expose that some giant species might be whisper through the ocean , hoping to sneak around without espial .

Scientists grouped different whale species into either “ fight ” or “ flight of steps ” sections depending on their reaction to orcas . whale in the engagement group – North Atlantic right whales , bowhead , Megaptera novaeangliae , and gray-haired whales – are slow - go , have their calf in shallow waters , and are typically those that stay and champion their calves from Orcinus orca giant onslaught . By contrast giant in the “ flight ” group – includingblue , fin , sei , minke , andBryde ’s whale – trip faster and have their young in the open sea , and will endeavor to pelt along aside from draw near orcas .

The fight and flying strategies definitely evolved in reply to killer whale depredation . Baleen whales have no other natural predators .

Interestingly , the study demonstrate that most flight of stairs specie , despite have some of the gimcrack call in the ocean , unremarkably ca n’t be heard by orcas more than 1 kilometre ( 0.6 miles ) away . Killer whales ca n’t detect song in the ocean of less than 100 cycles/second , and can only find out very loud sounds below 1,500 Gustav Hertz . The flight species typically produce noise of less than 1,500hz and are what is cognize as “ acoustically cryptic ” as a piranha avoidance strategy from killer whale whales .

“ The fight and flight strategies definitely evolved in response to killer whale predation . Baleen whale have no other natural vulture , ” canvas authorTrevor Branchtold IFLScience .

While fight mintage congregate together in groups for breeding in shallow waters , they often take vantage of their safety in number and will actively champion calves together . This is ready to hand for gentility since the giant do not have to go far to notice a mate . However , the male whales must impress the female with theirsongs . humpback , bowheads , and south right whales all produce elaborate songs to pull Paraguay tea .

For the flight species , there is something of a business deal - off . They must call loudly enough to appeal a mate , but not so forte that they head the sea wolf whales to their location . Flight mintage may also call at lower relative frequency since this travels further through the ocean .

The super - low , super - forte songs of flying mintage like blue and cinque whale are the perfect puppet : they can pull in a female person from hundreds of kilometers away , while being acoustically invisible to grampus whales .

“ To boom , species need to mate and breed successfully while avoiding predation . The super - low-pitched super - forte songs of flight coinage like disconsolate and tail fin whales are the stark prick : they can attract a female from century of kilometers away , while being acoustically invisible to killer whales , ” continued Branch .

By reviewing research on the unlike specie of heavyweight and their songs , the study found that flying species “ farm fewer call types , and their calls are generally simpler and more monotonous ” . All the fight species were physically capable of producing vociferation below the stove of Orcinus orca heavyweight earreach but alternatively call over a wide frequency range . The down in the mouth giant , which is the magnanimous flight metal money , produces sounds that a orca whale can not hear , with their garish sounds below 80 hertz . The same is truthful for fin whale , which call at frequencies even lower than blue whales .

Interestingly gray whales , which are a fight species , also do not call above 1,500 hertz . This could be explained by their movement and migration . " They [ grey whale ] transmigrate predictably close to shore when direct from wintertime genteelness to summertime eating ground , go with by their calves , which is when they are set on by cause of death whales . Perhaps this predictability , their little sizing , and the inability to have radical defence in shallow water ( unlike the Mexican laguna where they produce their calf ) , establish lower - absolute frequency calls more necessary , " explained Branch .

The cogitation also explore whymale whalessing the most , and explains that since the calves are more vulnerable it makes sense that the female have quieter call to shroud from killer whale predation attacks .

The paper is published inMarine Mammal Science .