DOLPHINS

Why in news?

Recently, A new study has found that noise generated by human activity makes it harder for dolphins to communicate and coordinate with each other. As the levels of underwater noise was increase then these mammals have to “shout” to each other.

What are the findings of the study?

• It was found that as it got noisier underwater, both dolphins changed their behaviour to communicate and work together.
• Apart from raising the volume and increasing the length of their calls, they also changed their body language they turned their bodies towards each other and swam across the lagoon to be closer to each other.
• Researchers noted despite these attempts to compensate for the noisy background, the dolphins had less success with the task.
• According to the study, cooperative task success decreased in the presence of noise, dropping from 85 per cent during ambient noise control trials to 62.5 per cent during the highest noise exposure.
• Previous studies have demonstrated that dolphins change their behaviour when they come across boats but, before the latest research, no one observed how anthropogenic noise can impact the coordination among these aquatic creatures.

About Dolphins:

• A dolphin is an aquatic mammal within the infraorder Cetacea.
• Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the brackish dolphins), and the extinct Lipotidae (baiji or Chinese river dolphin). There are 40 extant species named as dolphins.
• Dolphins range in size from the 1.7-metre-long and 50-kilogram, Maui's dolphin to the 9.5 m and 10-tonne orca.
• Various species of dolphins exhibit sexual dimorphism where the males are larger than females.
• They have streamlined bodies and two limbs that are modified into flippers.
• Though not quite as flexible as seals, some dolphins can briefly travel at speeds of 29 kilometres per hour or leap about 30 feet.
• Dolphins are widespread. Most species prefer the warm waters of the tropic zones, but some, such as the right whale dolphin, prefer colder climates.
• Male dolphins typically mate with multiple females every year, but females only mate every two to three years.
• Calves are typically born in the spring and summer months and females bear all the responsibility for raising them.
• Dolphins produce a variety of vocalizations, usually in the form of clicks and whistles.
• Dolphins are sometimes hunted in places such as Japan, in an activity known as dolphin drive hunting.
• Besides drive hunting, they also face threats from bycatch, habitat loss, and marine pollution.
• Dolphins have been depicted in various cultures worldwide. Dolphins are sometimes kept in captivity and trained to perform tricks.
• The most common dolphin species in captivity is the bottlenose dolphin, while there are around 60 orcas in captivity.

 

 

 

Source: https://indianexpress.com/article/explained/explained-climate/dolphins-coordinate-human-noise-pollution-study-8385113/