Have you ever wondered how the largest beings on earth, whales, sustain themselves? What do they eat? Whales have been swimming in our oceans for over 50 million years and have been a source of curiosity for scientists for centuries. Throughout that time, they’ve split into two main groups: Baleen Whales (Mysticeti) and Toothed Whales (Odontoceti). But, what does whales eat?
Whales’ diets provide insight into how they have adapted and survived. By studying what whales eat, we can better grasp their evolutionary success and the impact they have on marine ecosystems.
What Does Whales Eat?
Whales are a species that feed on an array of things throughout the food chain. Some feed on tiny ocean critters, zooplankton, and krill, while others feed on large schools of fish and squids. Let’s understand what does whales eat by categorising them:
1. Baleen Whales (Mysticeti)
The Grey whale in question has its mouth slightly ajar, revealing yellow structures hanging down. These structures are referred to as baleen, which is composed of the same material as hair and fingernails known as keratin.
Like hair, the baleen continues to grow if it breaks. Baleen teeth can reach lengths of up to twelve feet and are used to strain water like a big sieve in the mouths of large whales.
How do They Feed?
It takes a lot of fuel to sustain a giant creature. So, many of them rely on a technique called filtering to separate out tiny, edible critters from the water as they swim. There are two main techniques that they have developed, namely:
This feeding process is the most passive and energy-conserving method. When these whales spot a large school of fish just below the water’s surface, they open their mouths wide and swim through the fish.
They have expandable throat grooves from their nose to their belly button area, allowing them to take in huge amounts of water and fish at once. After engulfing a school of fish, their throats expand like a balloon but do not actually swallow.
Instead of swallowing the seawater, they close their mouths and spit it out using their large tongues through the baleen, which acts as a strainer or filter. This allows them to filter out the excess water and retain the prey promptly swallowed.
Bubble Net Feeding:
This method requires cooperation and communication within a pod of whales and is referred to as active hunting. It usually begins with following the ring leader; the whales dive down together, and each one moves into position.
The herders circle the fish with flashing fins, keeping the shoal contained and preventing its escape. Then there is the caller, the one who dives below the show and emits a deafening cry as loud as a rocket launch (180 DB of sound pressure) blasts through the water.
As an attempt to escape from the noise, the panic-stricken fish are driven upwards. This is where the ring leader comes in. Taking up the position above the school of fish, it begins blowing out a stream of air to create a fizzing net of bubbles
The shoal is prevented from dispersing by the herders and driven up by the caller right into the bubble net, where all the whales gather underneath the fish trapped in the net of bubbles with mouths wide open. They break into the surface, engulfing their prey.
Also Read: Best Animal Shelter In Sugar Land
2. Toothed Whales (Odontoceti)
Toothed whales are a group of marine mammals known for their hunting skills and social behaviour. They usually feast on larger mammals native to the sea, such as sea lions, giant squids, octopuses, and seals.
They have evolved to develop sharp teeth of about 30 – 60 in number only on the lower mandible. This group includes species like orcas and sperm whales. These whales have evolved over centuries to develop echolocation and deep-diving
How do They Feed?
Toothed whales are biologically equipped to survive in the deep ocean while in hunt for their prey. They use their teeth to grab on to their food but they don’t chew instead they just grab on and swallow their food whole, similar to baleen whales.
Something special about toothed whales is their ability to use echolocation. Echolocation can seem like a big, confusing word but it refers to their ability to paint a picture of their surroundings using sound. It works by emitting repeated chattering and clicking noise and detecting its echo.
Using this, they are able to detect the distance to an object or the sea floor by measuring the amount of time it takes for the reflected sound to return to them. They can also work out an object’s density and, thus, its material.
They have developed specialized air sacs situated near their blowhole to produce the sounds needed for echolocation. The air passes through the air sacs and past a structure called the phonic lips; the membranes of the phonic lips are sucked together, causing the tissue surrounding it to vibrate. These vibrations produce the clicks needed for echolocation, which are then focused and emitted as a beam through the melon.
Melon is composed of a mixture of triglycerides and wax esters. The vibrations are detected by an oil-filled channel in the lower jaw and conducted to the animal’s middle ear. In the middle ear, there is a fatty organ that transmits the vibration and converts it into an electrical signal to be sent to the brain.
Researchers have established that when swimming normally, whales emit low-frequency sounds, which are used to detect their environment, such as the depth of the water and shorelines. High-frequency sounds are thought to stun and disorient prey when hunting.
Another interesting fact is that in most toothed whales, the internal organs in the skull are squashed to the left so that there is enough room for the structures that help them echolocate. This gives them an asymmetrical head, and whales that live in extreme environments, such as sperm whales, belugas, and river dolphins, which rely on echolocation more than other whales, have an even more asymmetrical head.
Deep Diving:
With each breath, we humans replace only 15% of the air in our lungs, while sperm whales are able to renew 90% of their breath. Its muscles are rich in oxygen-carrying proteins and can store 10 times more oxygen than humans.
Sperm whales have a unique diet consisting of squid, sharks, and fish, requiring them to spend most of their lives in deep ocean water searching for prey.
As soon as it leaves the surface of the water, the sperm whale’s metabolism slows down to save oxygen, and its blood is concentrated on vital organs like the heart and its enormous brain, the largest in the animal kingdom.
Its huge head, 1/3 of its body length, contains a yellowish wax called spermaceti. It is believed that whales can vary the density of this substance at will.
To avoid decompression accidents in the bends, whales can collapse their lungs while still sending oxygen into the brain. They can dive to depths of over 1,000 meters (3,280 feet) in search of giant squid and other deep-sea creatures.
To Conclude
Whales have existed for millions of years and survived many changes in Earth’s climate and sea levels. Even though they were hunted extensively in the 1900s, their numbers are on the rise again. With this article on what does whales eat, one thing is for certain, though—these giants may all be eating small animals, but thanks to their massive body sizes and appetites, their meals are anything but tiny.
Also Read: Characteristics Of Temperate Grassland Animals
Three of my English major friends sitting around the table here, never knew that “whales” was a singular noun.
Interesting.
Maybe the AI programming thinks Wales is an alternative to Whales