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.
Australian marine scientists have discovered that the massive whale shark also eats plants, making it officially the largest omnivore on Earth.
As the evolution of a very large body size requires a ubiquitous and abundant source of food, the consumption of plants could present an energetic challenge for these animals unless some components can be digested.
Over the last few years, Fuvahmulah has become a world-famous pristine destination for close encounters with large tiger sharks. The green island is located at the deep south of the Maldives archipelago. Michel Braunstein reports.
Over a number of years, the actions of fishermen and sea anglers have attracted the attention of marine scientists at the Dunstaffnage Marine Laboratory who quickly became aware of these fishers catching spurdogs in the Loch Etive area near Oban on the west coast of Scotland.
It was found that with traditional fish stocks 90% overfished, sharks (along with tuna) have become the most lucrative prey for fisheries due to the value of their fins. So, with fishing scarcely profitable any more, fishing fleets around the world have joined in the hunt for them. The meat is pushed onto consumers using other names, so it is largely the shark fin trade that drives the so-called market for shark meat.
As a result, those species of sharks and rays accessible to fishing fleets are approaching extinction.
Devanshi Kasana, a Ph.D. candidate in the Florida International University (FIU) Predator Ecology and Conservation lab, was working with local Belizean fishers to tag tiger sharks when the surprise discovery was made.
New research, mentioned in a post on National Geographic, suggests that great white sharks can change colour—perhaps as a camouflage strategy to sneak up on prey.
A team of researchers from Murdoch University, the New England Aquarium and Mote Marine Laboratory who have been tagging and monitoring several species of sharks in the Gulf of Mexico discovered that some sharks share resources by foraging at different times.
Complex interactions and conflicts between protected populations may challenge the recovery of whole ecosystems. Several factors indicate that white sharks may be currently limiting the recovery of California sea otters.
Protected white sharks (Carcharodon carcharias) and pinnipeds have an established predator–prey relationship along the California coast.
White sharks are considered threatened by the IUCN Red List, and though they are protected at state, federal, and global scales, their current status in the northeastern Pacific is debated.
Text by David McGuire
Imagine witnessing a white spot moving quickly up from below. From a blur of white and gray, it turns into an open mouth, two black eyes, and large wing-like fins. In three seconds, the image transforms from a vague spot to a great white grin. Five rows (with two protruding rows) of around 300 triangular serrated teeth line a jaw of cartilage around one meter (three feet) wide in a mature great white shark sized around 5 to 6 meters (16.5 to 20 feet).
The great hammerhead shark is categorized as “critically endangered” by the International Union for Conservation of Nature. That’s the designation just before “extinct in the wild.” The species is highly threatened with extinction.
To that end, the Center for Biological Diversity has submitted a petition urging the National Marine Fisheries Service to protect the great hammerhead shark under the Endangered Species Act.
