Explanation:

 A group of up to 145 pilot whales have died after becoming stranded on a beach on Stewart Island in New Zealand… It’s not fully known why whales or dolphins strand. Possible reasons might be sickness, navigational errors, falling tides or being chased by a predator.

• Cetacean stranding, more commonly referred to as beaching, refers to the phenomenon of dolphins and whales stranding themselves on beaches. There are around 2,000 strandings each year worldwide, with most resulting in the death of the animal. Beachings are rare enough that they are not a significant threat to any species. The beaching of a single, live animal is usually the result of sickness or injury. Bad weather, old age, navigation errors, and hunting too close to shore also contribute to beachings.
• Some whale and dolphin species are more prone to mass beachings. Toothed whales (Odontoceti) are the most commonly affected. Toothed whales include dolphins, porpoises, and all whales with teeth. It is more common for these cetaceans to live in large groups with intricate social systems. If one member of the group is sick or in trouble, its distress calls can cause the other members to follow it to the beach, resulting in a mass stranding.
• Killer whales sometimes intentionally beach themselves to hunt for shoreline seals. They then wait for waves to help get back to sea. This practice is most commonly observed in pods around Argentina; it is believed that the habit is taught to younger killer whales by the older members of the pod. Killer whales very rarely become beached unintentionally.