Right whales have also been observed taking these strong stances to protect their vulnerable calves. To defend against killer whales, for example, such whales have been reported to group together and defend themselves with powerful tail, pectoral fin or head blows at their attackers. For them, a fight rather than flight defence strategy against predators may be taken. Some other baleen whales, such as southern right whales that can reach over 16m-long, are less streamlined than blue whales due to their chunkier, but more flexible, bodies. Unless you’re a large shark, say, over several meters long, you simply may not have sufficient power in your jaws to effectively tear off the meat, even if you could keep up with a blue whale. AAP Image, Mike Johnson/Australian Antarctic Divisionīut the difficulties for a shark in capturing a blue whale don’t end with their limited endurance at high speed. This is how blue whales maximise their energy intake while minimising effort.īlue whales can unhinge their jaw and take in thousands of litres of water. Instead of teeth, blue whales (along with humpbacks, and many other whale species) have bristle-like baleen, which strain the small organisms from the water when their mouth cavity is compressed. With this remarkable device, blue whales can engulf thousands of litres of water in one go. The lunge builds enormous water pressure against their mouth, inflating the pleat-like grooved blubber around their mouth cavity to balloon like an accordion’s bellows. They lunge through dense patches of thousands, if not millions, of krill, with large, gaping jaws that can open up to around 80 degrees. Rather, they evolved an efficient way of consuming very large amounts of tiny prey: krill. Marcelo Cidrack/Unsplash, CC BY A grand banquetĪt up to 30 metres long and weighing over 100 tonnes, a blue whale easily outsizes a white shark, which can measure perhaps over 6m and weigh less than a tonne.īut the blue whale didn’t get so big from killing and eating other large animals such as sharks. Depletion of this predator due to overfishing may be leading to unknown cascading top-down effects in the mesopelagic realm.White sharks have teeth designed to rip flesh. Blue shark feed on a large variety of passive pelagic prey, mainly mesopelagic cephalopods, that could be preyed upon as well as scavenged. A thorough review of studies on blue sharks stomach contents analysis is given. Tiny diet differences due to shark size or sex were inconclusive. Diet varied greatly between months with no clear seasonal pattern. Other prey included teleost fish, amniotes and floating items. The single most abundant prey was the pelagic, red crab Pleuroncodes planipes (41.7%). Feeding habits and the probability of scavenging on mesopelagic cephalopods is discussed. constitutes the first record for Mexican waters. A pair of beaks of giant squid Architeuthis sp. and Vampyroteuthis infernalis were also abundant prey. The most abundant (17%) and frequent (32%) was Histioteuthis heteropsis and the most important by estimated weight (22%) was ‘Gonatus californiensis’. A large variety of pelagic cephalopods occurred in 55.5% of all stomachs and accounted for 46.2% of all prey and 84% by estimated weight of stomach contents. Stomach contents of 893 blue shark ( Prionace glauca) caught off Ensenada, Todos Santos Bay, Baja California, from 1995 to 1997 were analysed.
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