So I asked leading shark ethologist and behaviourist, Professor Samuel 'doc' Gruber to elaborate. After pointing out how much pain women feel when they give birth, making the point that suffering has no effect on reproduction, he reminded me that sharks evolved their mating behaviours and the physical structures involved, separately from other animals.
Hopes that shark cartilage would prove to be a useful treatment for cancer were not borne out in one of the most rigorously designed and executed studies of an alternative therapy ever conducted. Adding a drug derived from shark cartilage to standard cancer treatments did not improve survival among patients with late-stage lung cancer in the study.
While using the liver as an energy store and for buoyancy is well documented in adult sharks, this study provides the first evidence of a decline in liver mass of newborn sharks, from 20% of body weight at birth to 6% when they start to feed themselves.
Research by a Bangor University-led international team found that during the critical period after birth, shark pups lose weight by consuming their liver reserves. This weight loss is not necessarily an indicaton that the sharks are in a poor nutritional state, as has been previously thought.
A new 4-million-year-old fossil from Peru described in this month’s issue of the Journal of Vertebrate Paleontology provides important evidence suggesting the shark’s origins may be more humble than previously believed.
Dana Ehret, Gordon Hubbell and Bruce MacFadden studied an exceptionally well-preserved fossil of a species of white shark (Carcharodon sp.) from Peru (estimated to be about 5 m long by the authors), consisting of a complete jaw with 222 teeth, and 45 vertebrae, in their paper.
Researchers believe this quality could be harnessed to help slow the spread of diseases such as cancer.
Potentially, it could lead to a new generation of drug treatments.
The Australian team found that shark antibodies can withstand high temperatures as well as extremely acidic or alkaline conditions.
The minute scales, which are just 200 micrometres long, are made from tough enamel, such as that found on teeth, giving the skin a rough texture like sandpaper. Lying flat, they had previously been found to reduce drag as the shark swims. Some reports had also suggested that sharks can bristle their scales, causing them to stand up on end.
Experiments have now revealed that tiny vortices or whirlpools formed within the cavities between the scales.
