A total of seven large dolphins died in Brazil over the weekend after they beached themselves in the northeastern Brazilian state of Rio Grande do Norte, according to local media.
The country's Upanema beach, located about 330 km from Natal, the capital of Rio Grande do Norte, was the site where 30 dolphins were left stranded on Sunday, O Globo reports. Local fishermen and volunteers assisted in helping the large mammals back into the water and all but seven made it back out to sea. Six of them died on Upanema beach, while one animal died following an apparent shark attack after it was returned to the ocean.
The report emphasized that the dolphin was likely attacked in very deep waters and that area beachgoers needn't worry about shark attacks.
Local biologists have not given a reason as to why the dolphins beached but a common cause for this phenomenon is when the group's leader may strand itself due to illness or injury, swimming in close to shore to take refuge in shallow water. Since dolphins are highly social creatures that travel in communities called pods, such mass strandings may occur when healthy whales refuse to abandon a sick or injured pod member and follow them into shallow water.
Another hypothesis is that the dolphins were pursuing a school of fish and were trapped on Upanema's high sand banks.
According to the report, this was one of the largest collective beachings in Brazil in recent decades. In 1991, around 19 whales beached themselves on the sands of the nearby town of Sao Miguel do Gostoso.