Orcas are among the largest and most powerful predators that inhabit the world’s oceans. These apex predators have a diverse diet feeding on fish, as well as marine mammals such as sea lions dolphins and even other whale species. Despite their worldwide distribution not much is understood about how they behave within the Humboldt Current System a region abundant in nutrients, located off the northern coast of Chile in the South Pacific Ocean.
A study conducted by García-Cegarra and a team of researchers has recently revealed new insights into the behavior of orcas in this specific area. Unveiling the first documented cases of orcas preying on dusky dolphins and attacking fin whales.
Study Overview and Sightings
From 2010 to 2023, reports indicate that there were 28 sightings of killer whales in northern Chile. Most of these sightings occurred around the Mejillones Peninsula and the Humboldt Penguin National Reserve. The research involved a mix of information collected, from whale watching enthusiasts, fishermen, and boat surveys. Apart from studying the movement patterns of the orcas the team also observed their hunting strategies which included the unprecedented occurrence of killer whales hunting dusky dolphins in that area.
Orcas’ Hunting and Food Sharing
There is an interesting event where a pod of killer whales called the Menacho pod was spotted hunting and consuming dusky dolphins. Once they caught the dolphin the killer whales distributed the meat among themselves demonstrating a behavior often seen within killer whale families. The leader of the pod was observed feeding a calf and showing the young killer whale how to eat the prey. This act of sharing food emphasizes the social behavior of killer whales as they collaborate and impart hunting techniques to the next generation of killer whales.
Increasing Sightings and Variety of Prey
The research also revealed instances of killer whales attacking bigger animals such as fin whales ( the second-largest species of whale, after the blue whale ). In certain cases bite marks from the killer whales were spotted on the fins of these enormous mammals. The increasing occurrences of killer whales preying on dolphins and whales in this area indicate that their population and hunting behaviors might be on the rise along the coast of Chile.
Orca Intelligence
Orcas, are creatures with high levels of intelligence possessing intricate social dynamics and impressive abilities. They have a penchant for sharing hunting strategies and group behaviors through observational learning, notably from experienced females to younger pod members. Tragically the cognitive and emotional capacity of orcas has become apparent in captivity as some individuals have shown signs of depression. Such as an instance where an orca was observed vocalizing the word “die” to itself. This emotional distress has sparked scrutiny over the practice of keeping orcas in captivity prompting. Various aquariums like SeaWorld in the U.S and Marineland in France to face calls, for ending their shows involving orcas. Consequently there has been a gradual phasing out of orca captivity in several areas, with restrictions on acquiring new orcas for marine parks.
This study offers new insights into the behavior of orcas within the Humboldt Current System. However, there is still a lot to learn about these apex predators. The researchers emphasize the need for further investigations to develop a comprehensive knowledge of the prey species targeted by orcas in this region and determine the existence of different orca ecotypes. Improving our understanding of their behaviors and interactions is crucial for the conservation of both orcas and their prey in the South Pacific, considering that these captivating creatures harbor many mysteries just waiting to be unveiled.
Source: https://doi.org/10.3389/fmars.2024.1450624
Credits: Wonder World, Oceanwide-expeditions
Ana M. García-Cegarra, Javier Oña, Camilo Arancibia, Luis Aguilar, Frederick Toro