cracking white shark , while not the grotesque military man - feeder that pop culture makes them out to be , are peerless when it comes to hunting in the unfastened sea . Their place at the top of the oceans ’ intellectual nourishment string is due in part to their speed , size , and extremely developed skunk , but there ’s also some strategy postulate — include one aspect that scientist have never seen before in any animal besides humans .
Sharks hunt primarily at dawn and dusk , and there ’s a good reason for that . Earlier this year , researchers in Australia establish thatgreat whites work the Sun ’s low positionduring these times to help them stalk and attack their quarry .
The researchers , led by life scientist Charlie Huveneers , went out to sea in a boat off the sea-coast of South Australia and entice sharks to lash out a chunk of tuna that they moved around on a sportfishing business line to mimic live prey . They did this both in the morning and afternoon , on both sunny and overcast day . Whenever a shark go for the bait , they noted the fish ’s sex , size of it , and any identifying marks , as well as the direction it approach from and the position of the Sun . During 30 of these trips over the course of a few month , they record 579 “ predatory approach ” on their tunny by 37 different sharks .
On cloudy solar day , the researcher get hold that the sharks approached the tunny from all unlike focal point , but on sunny days , a radiation pattern emerged . On sunny aurora , the sharks mostly approached from the Orient , and primarily came at the tuna with the Sun directly behind them . In the afternoon , the sharks change things up and mostly approached from the west — again , mainly with the Sun behind them .
The convention did n’t correlate with factors like the situation of the gravy holder or wind focusing , which would affect the diffusion of the tuna ’s odor , lead the research worker to think that the shark track the military position of the Sun and exploit it while hunting .
This is the first grounds of any nonhuman animal using the Sun as part of their depredation strategy , and there are several benefits for shark approaching prey with the Sun behind them . First , Huveneers and his team say , it make it comfortable for a shark to detect and identify likely meal because the Sun is n’t in the shark ’s eyes . It also direct illuminates the side of the prey front the shark and makes it stand out against the background knowledge .
draw close from the same direction as the Sun can also assist keep a shark veil from its target area . Prey whose heads are above the water , like seals or seabirds , would see glare on the water ’s Earth’s surface in the direction of the Sun , which would hold back an oncoming shark below the surface .
If this is in fact what the sharks are doing , it ’s a pretty impressive skill . shark would need to keep track of the Sun ’s wobble lieu over the course of study of the day , and its position proportional to a impress quarry aim and during each approaching . adjust their approach in answer to two different changing cues is n’t a trivial cognitive chore , the researchers say , and suggest we should be giving sharks more credit for having wit as well as sinew . In future discipline , the team desire to explore the cognitive ability that let them use this unique tactic .
