Animals around the world adapt and change behaviors to raise their chances of survival. One form of this is evolution, which is a slow-moving process that takes many generations. Another form of this is through necessity, which is quite fast-paced and happens within one generation. An example of a necessity adaptation is that some orcas beach themselves to hunt.
The orca, or killer whale as it is colloquially known, is actually a dolphin rather than a whale. Humans easily recognize the distinct black-and-white patterns on their bodies. Though orcas are mammals and breathe air, they spend their entire lives in the water. They are built to swim and will die if they go too far ashore. So why do some of them risk their lives while hunting? Let’s find out.
About The Orca
Colonization threatens the orca in the form of overhunting, prey depletion, habitat loss, and pollution. Orcas are also either killed for interfering with human fisheries or captured for inhuman marine mammal parks.
The worldwide population of orcas is approximately 50,000, according to the National Oceanic and Atmospheric Administration (NOAA) Fisheries stock assessment reports. The orca is classified as endangered. Because of this, the marine predator has quickly had to adapt to survive.
The orca is a highly social animal. Each individual belongs to a pod and spends more than half of its time in the group. The pods usually consist of maternally related individuals and most individual orcas stay within their natal pod. A pod can have anywhere between five and over 20 killer whales. During mating seasons and whenever prey is concentrated, humans can observe larger groups gather.
Orcas sometimes have reunions in which two or three pods will gather together. Some members of each pod are usually related. The pods will face one another and spend a few moments in silence, simply staring. Then, they will rush one another, swim in circles, slap one another with their tails, and breach the water’s surface.
Unlike other animals, orcas do not have a distinct breeding season. Most commonly, the animals will breed in the summer. The birthing animal gestates for 15- to 18- months and then will give birth to one baby, called a calf. The parent will nurse the calf for up to one year.
After the nursing period, the offspring will most likely stay with its parent in the same pod for its entire life. One pod will contain as many as four generations. In general, birthing orcas live about 20 years longer than inseminating killer whales.
Humans can see orcas in every ocean on the planet. The three distinct types of orcas are transient, resident, and offshore. Each kind of orca is genetically distinct and will not mingle or interbreed with the others. The resident killer whales live close to the shore. They live in pods that consist of about ten to 20 individual animals. The resident orcas primarily eat fish.
Offshore orcas tend to be smaller than residents, though they exhibit the same behaviors. Between offshore killer whales and residents, the pod sizes and diet are the same. The offshore orcas will also have rounded or nicked fins. Transient orcas live in pods of three to seven individuals. They live out in the open sea and eat seals, sea lions, and other dolphins.
The orca is a predator and has a complex, highly individual diet. Each ecotype of killer whales will feed differently. Orcas that live close to the shore in the U.S. Pacific Northwest will exclusively eat fish and have a taste for fatty salmon and herring. Orcas living farther out in the ocean in the same area eat marine mammals and squids. Other orcas will hunt and kill sharks and rays, aiming for vital organs like their livers. Adult orcas must each eat about 500 pounds of food per day.
The orca hunts in packs and uses a coordinated hunting strategy to chase their prey. The highly intelligent animals will herd prey into a small or isolated area before attacking it. Orcas will toss around their food until it is dead, then consume it together. The killer whales communicate their plan using clicks, whistles, and pulsed calls. Each individual and pod has a unique set of calls that distinguishes them from other individuals and pods.
So, Why Do Some Orcas Beach Themselves to Hunt?
On the Peninsula Valdes, researchers observe two orcas, Mel and Maga, beach themselves to hunt. The animals use the force of the sea to propel themselves past the water’s edge. With the element of surprise, they seize unsuspecting seals and sea lions. After successfully grabbing prey, the orcas push against the smooth, round beach stones and allow the surf to bring them back into the ocean.
Because Mel and Maga are the leaders of their pod, they share this technique with the other members. The animals began beaching themselves to have more access to food. The technique most likely developed out of a necessity to diversify food sources.
The photo featured at the top of this post is © Foto 4440/Shutterstock.com
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