Could whales survive in the Great Lakes?

Adaptation to marine life

As mammals, whales and dolphins have to keep their body temperature constant in the cold sea. And last but not least, life in underwater social communities required new forms of communication.

Lightweight construction

The conquest of the seas required numerous morphological and physiological adaptations to the new habitat. Thanks to the buoyancy in the water, even very large animals such as blue whales do not need such a pronounced skeletal system as on land.

The whale bones no longer have to fulfill such a large support function. Many parts of the skeleton were therefore reduced in the course of evolution. Today, to save weight, they are porous and filled with oil.

Bacon coat as protection against the cold

Cold water draws much more heat from the body than air. However, like most other mammals, whales have to maintain a constant temperature of 36 to 37 degrees Celsius, otherwise the cardiovascular system fails.

For thermal insulation, the large whales roaming the polar regions have put on a layer of fat up to 50 centimeters thick, the so-called bubbler. It also serves as an energy reserve.

At the same time, whales have sophisticated temperature regulation mechanisms in order to be able to adapt to extreme temperature changes.

In order not to overheat in warm tropical waters, they increasingly bleed through their outer skin and keep the temperature difference between the inner and outer environment small.

In the ice-cold polar seas, on the other hand, they restrict the blood flow to the inside of the body in order to lose as little heat energy as possible.

Water resistance control

Since water is much denser than air, movement in it is correspondingly more difficult. Due to their streamlined shape, the whales have extremely reduced their water resistance in the course of their development. And with a very special trick they lower it even further.

Turbulence would normally form on the smooth, soft skin of the whale while swimming. These turbulences increase the water resistance and would slow the animals down considerably with their large body surface.

But whales are able to feel the resulting eddies with pressure sensors and to balance them out with fine skin grooves.

Deep sea divers

Since they cannot breathe underwater, the whales have adapted their oxygen balance to life underwater. So that you do not lose sight of what is happening while breathing, your nostril or blowhole has moved to the back of your head.

With one breath you can exchange 80 to 90 percent of the air you breathe. In humans it is just ten to 15 percent.

So that they do not run out of air on longer dives, whales can store oxygen much better than land mammals. The blood of whales is more enriched in hemoglobin, a molecule that stores oxygen.

Whales can absorb significantly more oxygen into the blood and store it temporarily in the muscles. The entire energy generation system is extremely efficient.

Enigmatic spermaceti organ

Sperm whales are the record divers among whales: some are said to have penetrated 3000 meters below ground and remained under water for up to two hours.

The sperm whales presumably make diving easier with a mysterious part of their body in their huge head. It contains up to several tons of a strange, usually liquid substance. Before diving, the whales will likely cool and solidify this whale rat so that it condenses and pulls the whale down.

Probably because of its white-yellowish color and waxy, oily consistency, the whale rat is also called "sperm oil" in English, sperm whales are called accordingly "sperm whales".

It is now clear that this enigmatic spermaceti organ supports the long dives rather than the reproductive power of sperm whales.

Good sense organs

Most whales, like many other mammals, also have well-trained eyes. Since the visibility in the water is much worse than on land, the whales have specialized in other senses in the course of their development, especially hearing and touch. Smelling is rather underdeveloped.

They use their sense of taste to determine the salt content or to recognize related conspecifics by their urine. Baleen whales are also likely to taste their prey. Schools of fish and krill leave behind a trail of excrement, which the whales follow.

Natural compass

Whales are not only able to perceive their often cloudy and dark environment precisely, they also have amazing orientation skills. Some species migrate several thousand kilometers. How they find their way is still not entirely clear.

Magnetizable crystals have been detected in the heads of humpback whales. Many researchers therefore assume that some whale species orient themselves to the earth's magnetic field, similar to migratory birds.

However, this magnetic sense is probably not the only orientation aid, but rather just one element of an inner hiking map composed of several sensory impressions.

Bats of the seas

Toothed whales not only listen to sounds, but have also learned to scan their surroundings with ultrasound, similar to bats. To do this, they generate click sounds far above the human hearing range, which spread underwater. Obstacles reflect these clicks and generate a returning echo.

Since the speed of sound varies only slightly underwater, the toothed whales can use the delay in the echoes to determine how long the sound was traveling and use this to estimate distances.

With these ultrasonic clicks, toothed whales can even scan their entire environment and form a complete picture from the returning echoes. To do this, they direct the sound with a round, fat-filled organ behind the curved forehead, the melon, like a lens in different directions.

Precise biosonar

Using the same principle, sonar devices on ships also scan the underwater world in order to find submarines or schools of fish, for example. However, the biosonar of toothed whales is more precise than any technical sonar.

With their echolocation, dolphins can easily recognize wires that are only a few millimeters thick and achieve a better resolution than the human eye.

Since the sound can penetrate the body like a medical ultrasound device, some researchers even believe that it is possible that toothed whales can use it to identify the state of health of other species.

Loud hunting sonar

Sperm whales, the largest toothed whales, generate the loudest noises in the animal kingdom with their clicks. In the water they reach up to 230 decibels and are therefore roughly as loud as the most powerful military sonar devices. In the air it would be much louder than a rocket engine.

Some researchers suspect that the whales not only orientate themselves and communicate with each other with these clicks, but also stun their prey - giant squids at depths of over 1000 meters - with the extreme sound pressure.