Activity levels of Nautilus in the wild
Article Abstract:
A study of the activity levels in the wild of the Nautilus is reported. The aim was to understand why nautiloids survived relatively unchanged from the Ordovician, while ammonites and all other ectocochleate cephalopods became extinct. The study involved obtaining high-resolution tracks of animal position and depth and telemetered jet pressures to examine animal lifestyle and economics. The results showed that Nautilus is more active in the wild than in captivity, but expend less energy. The animal reduces transport energy costs by taking advantage of vertical movement. Also, it moves to deeper, cooler waters after feeding to allow a single feeding to last longer.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1993
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Nautilus and the art of metabolic maintenance
Article Abstract:
The cephalopod mollusk Nautilus can survive for at least a day in severe hypoxic environments by suppressing its aerobic metabolic rate to 4 to 8% of that at normal oxygen levels. The reduction in metabolic rate decreases the activity level with interspersed periods of high activity followed by longer inactive periods. The ventilatory processes stop, cardiac output decreases and the heart beat slows down. The blood that has a high oxygen affinity is oxygenated at the venous end across the superficially loaded vena cava.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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Why squid can breathe easy
Article Abstract:
Squids in the cold deep oceans have huge gill areas and low blood-water barrier thicknesses which allow them to survive in low oxygen areas. The gills are very fragile and are not a part of the buccal apparatus. This removes the danger to the gills from sharp bones and pieces of cuticle. The squids have a high oxygen diffusion ability and can move quickly even in areas of low oxygen. The high oxygen diffusion rate is probably the reason for the large number of cephalopods present in the deep seas.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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