Shark eggs also know how to detect enemies

Embryos of sharks that are still growing in eggs have been able to sense predators' electric fields and 'freeze' in place to avoid detection, according to a new study.

Many species of sharks that lay off their babies in a rectangular egg bag are called 'mermaid's purse' or 'devil's purse'. These egg bags often have long tails at each corner to help them anchor to surfaces.

Parental sharks always use highly sensitive electrode receptors (known as Lorenzini's 'ampullae senses' ) to detect electric fields due to muscle contractions of potential prey. . Recently, Australian scientists discovered that their embryos also have similar capabilities, helping to detect the enemy's electric field to avoid being eaten.

During 5 months of growth within the egg bag, the embryo
of zebra sharks have been able to detect guys' electric fields
Vengeance and deal by completely immobile. (Photo: Live Sicence)

Researchers have focused on the understanding of the tiger shark, the scientific name is Chiloscyllium punctatum. Their embryos take up to 5 months to grow inside floating egg sacs in the ocean, so they are vulnerable to fish, marine mammals and even large mollusks.

The team found that even when residing inside an egg pocket, the embryo has the ability to detect simulated electric fields of enemies such as fish in the laboratory. According to video recording results, growing baby sharks deal with the signal obtained by stopping all of their gills and keeping the body in full motion.

Scientists say the findings could help develop more effective anti-shark drugs by releasing electric fields to drive them away.

This could be a means to ensure human safety while protecting sharks that are rapidly declining worldwide each year, mainly due to unintentional entanglement in fishing nets.

Researcher Ryan Kempster from the University of Western Australia said that the danger people create for sharks is far beyond what they create for us.'In an effort to turn the ocean into a safer place, governments in Western Australia, Hawaii and the French Reunion island have implemented the killing of sharks.

Given the essential role of sharks on oceanic ecosystems, I believe it is more appropriate to take measures to control sharks without killing factors, such as chasing away electric fields. " Mr. Kempster stressed on Live Science.