VIDEO: Bamboo sharks play dead
WHILE WORKING ON his thesis for the University of Western Australia, Ryan Kempster made a fascinating revelation about bamboo sharks. When faced with predators, the embryos of this species – developing within their egg cases – will shut down, he says, effectively “playing dead”.
The embryo will actually stop respiring, remain completely still and greatly reduce its heart rate, making it difficult for predators to detect it. The bigger the threat a predator poses, the longer the amount of time that the embryo will play dead, he says (see video above, courtesy of UWA).
Baby bamboo sharks are able to use vibrations to track movements, but they also have an electro-sensory sense that uses biological electric fields to detect movement. These tiny embryos use their electro-sensory pores to detect predators, such as other sharks.
Electric sense of sharks
Commonly found in the Indo-West Pacific region, near the southern coast of New Guinea and the northern coast of Australia, these full-grown, nocturnal bottom-dwellers have other unusual defences too. As adults, they have the ability to survive in low oxygen conditions by switching off non-essential brain functions, and can also survive up to 12 hours out of the water.
Though adult bamboo sharks usually eat small fish, and seafloor invertebrates, such as crabs, Kempster says that they would probably eat their own newborns, if it weren’t for a secreted hormone that reduces their appetite.
Ryan Kempster’s short film documenting the phenomenon, Survival of the Stillest (above), will be shown this week at the prestigious US film festival, Beneath the Waves, in Norfolk, Virginia.
RELATED STORIES
Why sharks attack and how to avoid them
Great white sharks attracted by AC/DC hits
Shark attacks in Australia: a timeline
Are humans to blame for shark attacks?
10 myths about sharks: the truth
13 tips for avoiding a shark attack
Great white shark nursery
Shark attack increase blamed on humans
Mediterranean’s sharks originated in Australia
New shark repellents under development
Shark attack survivors unite to save sharks
Sharks are fantastic navigators
Sharks are colour-blind, new study finds
Great white shark freed from plastic noose
State of our oceans
Outrage over plans to cull sharks in WA
Whale shark spotted in the Southern Ocean
…More shark stories
