Researchers documenting the behaviour of humpback whales off the coast of Canada have discovered some unique feeding habits being adopted by the whales.
A team from the Marine Education and Research Society in Canada observed the group of humpbacks using a ‘venus fly trap’ method of feeding on unsuspecting young herring off north eastern Vancouver Island.
It is believed that this method of feeding has not been seen used by humpbacks in other locations.
The trap feeding begins with the whale floating at the surface of the water with his or her mouth open and using its pectoral fins to slowly draw water containing the fish inwards.
On average, the whales keep their mouths open 18 seconds but as long as 90 seconds before closing and trapping the fish. The researchers believe that herring are using the huge whales as some form of protection or shelter from the threat of attack by seabirds above, unaware that they are actually entering a trap set by the whales.
Various seabirds circle above looking to dive and pick off the herring, so the fish form large protective groups called bait balls in the hope that they won’t get taken one by one. When the birds start to gather to begin their feeding frenzy, the whales will appear and gobble up these tight schools of fish.
Normally humpbacks use a tactic known as lunge feeding to target larger schools of herring, and so it is thought that this trap feeding might be adopted when there are fewer fish around. Humpback whales feed in the rich waters off Vancouver Island before they head to warmer water in places like Hawaii or Mexico to give birth.
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