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.
Anyone who has faced an agitated shark has felt the power of communication through body language. The response is so immediate and so physical, that emotion, expressing through body language, is revealed as an important medium of pre-vocal communication among animals.
Brown-banded bamboo sharks can sense electrical fields even before they've hatched from their egg cases.
Despite being confined to the small space within the egg case, where they are vulnerable to predators, embryonic sharks are able to recognise dangerous stimuli and react with an innate avoidance response.
Normally, an embryo pulses its gills actively. But when researchers turned on electrodes to produce an electric field near the egg cases, the unhatched sharks froze and stilled their gills for several seconds.
‘Banba’ a female basking shark tagged in July with a satellite transmitter off Malin head, Co. Donegal has just released its transmitter west of the Cape Verde Islands, over 5000km away from were it was originally tagged.
The movement by the shark ‘Banba’ into warm tropical waters off West Africa coupled with similar findings by Mattew Whitt working with Scottish Natural Heritage and leading American shark biologist Greg Skomal in the western Atlantic, questions the validity of the established theory that basking sharks inhabit temperate waters only.
Research has revealed that bull sharks bite with almost 6,000N, a force that is greater than what is required to kill and eat prey. In a study published in the journal Zoology, Maria Habegger from Tampa’s University of South Florida, along with colleagues in the US and Germany, examined bite forces produced by 13 shark species and their close relatives, ranging from 1m-long ratfish to the great white shark.
The PhD study bt Dr. Susan Theiss showed that the wobbegong visual system contains only a single class of cone photoreceptor. Cone photoreceptors are the retinal cells that are used for vision under bright light conditions, whereas as rod photoreceptors are used in dim light.
These previous studies looked at opsins, which are light-sensitive proteins found in the photoreceptor cells of the retina. Rod opsins are used in low light and produce a black and white image, while cone opsins are used in bright light, and often to see colours.
One of the dreams of any naturalist is to be the first to find and detail the life of a hidden or unknown animal first hand. Since 2003, scientific divers with the Greenland Shark and Elasmobranch Education and Research Group (GEERG) have begun to unravel the mysterious life of the Greenland shark, which at over seven meters in maximum body length and exceeding a ton in weight, is the second largest carnivorous shark after the great white.
To gain a better understanding of how sharks manage to keep their teeth in such pristine condition, a team of German researchers looked at two species that eat in very different ways
The researchers looked at Isurus oxyrinchus and Galeocerdo cuvier (mako and tiger sharks) and found, as they explain in their paper published in the Journal of Structural Biology, after very close examination, that the outer coating of the shark teeth contained one hundred percent fluoride.
Scientists identified two distinct populations of white shark at the east and west of Bass Strait in Australian waters, prompting researchers to suggest the huge fish may need a regional conservation plan.
Announcements in June, 2006 reported the discovery of a possible new species of hammerhead off the US eastern seaboard.
Nearly seven years ago, scientists from Nova Southeastern University Oceanographic Center sampling sharks caught on charter boats off Fort Lauderdale and South Carolina stumbled on a startling discovery: some of the sharks that looked like scalloped hammerheads were actually a different, unidentified species.
Maybe the concept of ‘responsible shark diving’ sounds a little oxymoronic, but there are many things that you can do to protect yourself and the sharks during your interaction. First and foremost, I can’t stress enough the need to gain as much knowledge as possible about the animals and their environment. To go into the water without at least a basic idea of how the sharks are likely to react is foolhardy to say the least.
