human being have observed marine mammal strand themselves on body politic since at least the first century CE , when the ancient Romans and Greeks commemorate beach incident . New marine biologists are only able-bodied to limit the campaign of a beach about 50 pct of the prison term , according to the Woods Hole Oceanographic Institution , and the reasons they see are wide-ranging .
Often the campaign is obvious injury or malady . Disease or wounds from predators can leave an animal too weak to keep itself afloat , and at some power point it pay up and lets the tide wash off it ashore .
Cases where a group of animals beach themselves together , and not all of them exhibit signs of trauma , are more puzzling . One explanation life scientist offer is that whales and dolphinfish , which Leigh Hunt and travel together in groups called seedpod , fall down dupe to their own social construction . If the group loss leader or prevailing animal is unbalanced or hurt and runs ashore , the rest of the group might follow . Other times , the pod may just get itself stuck by a low lunar time period after hunting or traveling too close to shore .
In some case , pot beachings have pass shortly after fighting use of military sonar in an area . In 2000 , for good example , 17 animals from four metal money ( Cuvier ’s pick hulk , Blainville ’s beaked whale , Minke whale , and the spotted dolphin ) were found beach within a 36 60 minutes period in the Bahamas the day of , and after , a U.S. Navy sonar exercise . A joint Navy and National Oceanic and Atmospheric Administration ( NOAA ) probe soonconcludedthat the tactical mid - range frequency sonars used by the Navy ships “ were the most plausible source of the acoustical or impulse trauma ” that occured . The evidence suggests that sonar may have bothphysicalandbehavioraleffects on maritime mammals .
Some animals also beach themselves purposefully as a hunt maneuver . Killers whales , or orcas , frequently chasepinnipeds , like seals and ocean lions , into the breakers zone and onto shoring , where the quarry has to make a clumsy transition from swim to walking in shallow , roiled urine . As the fair game struggles to escape , the orca launches itself , or rides a undulation , onto the beach and grabs the prey in its jaw . After the meal is secured , the killer can either wriggle back into deeper water or let a magnanimous undulation go up it off the ground and back out to ocean .
