What kind of animal do you guess is this?
Can you imagine that this was actually the first ancestor of whales and on top of that he was only as big as a rabbit!
As you probably know whales are mammals and they belong to the group called Cetaceans along with dolphins and porpoises. 55 Million years ago this small hairy mammal called Diacodexis used to live at coastlines of the seas and hunted crustaceans like crabs and small fish. However due to volcanic activities the sea levels started to rise gradually coasts were flooded and other predators were much better equipped and suited for the land. In order to survive he had to specialize and adapt his hunting strategy.
While other animals during the evolution of life were busy crawling out of the sea he had no choice than going the other way and jump back in.
To search for prey he began to go further and deeper in the ocean, continued to develop and over time he changed his appearance. He lost his hair, front legs turned into pectoral fins he didn’t need his back legs anymore and his tail was one day suddenly a fluke. The nose holes on his snout were not practical underwater anymore because he had to get his whole head out of the water to breathe. So they moved further up on his head and are now the so called „blowholes“.
Ok so we can kind of believe now that whales were once these hairy dogs
but how on earth did they grow so big ??
Blue whales are the biggest animals who have ever roamed the planet. With 33 meters they have the length of a basketball court, they are as heavy as 40 african elephants, their heart is as big as a small car, and their toungue equivalents an elephant.
Curiously enough the biggest animal on earth feeds on the tiny tiny shrimp like creatures called Krill (not bigger than a finger 1-2 cm).
Because they are like chips for them or rice corns little sushi rolls which wont make them full they want to get as much as possible in their mouths. So they use the method called lunge feeding:
Some feed by swimming with their mouths wide open and filter the sea from krill like a vacuum cleaner, others open their mouths and take in huge amounts of water and expel it afterwards. They expand the mouth and open it widely, engulp large quantities of prey and water (with each gulp 125% of its body weight). Then he needs to expel the water and obtain the yummy krill. So they close their mouths use the tongue to push out all the water through the baleen filters. Baleen plates (filtering system like teeth arranged in a comb)
So it is partly their diet which provided them the energy to grow so big: whales eat around 4 tons of krill per day. (One mouth of krill – 480 000 calories – 1900 hamburgers) But it could be also because there is no gravity underwater. Buoyancy counter acts the pull of gravity on their bodies. Others believe their size increased suddenly: 2.6 mio years ago the oceans temperatures started to cool down, currents shifted, it was the ice age which fertilized the growth of plancton and krill at coast regions. In result suddenly whales could eat more compared to other predators. And only they were able to migrate such long distances to the feeding areas. However it is unsure due to global warming if this advantage could be a disadvantage in the future.
How whales change the climate:
Whales dive in deep depths to feed and when they come up to the surface again they release enormous poop (whale pump: brings essential nutrients from the depth to the surface waters, more whales pooping – stimulates the growth of plankton). More plancton means more animal plancton which means more fish. But plant plancton not only feeds the animals at sea it absorbs C02 from the atmosphere as well. Because whales eat so much plancton they transport 190 000 tons of carbon (80 000 cars per year). So they could undo some of the damage we have done!
Whales mix the water vertically (during their long migrations) and horizontally (when they dive into the deep or when they breach)
Furthermore their big bodies store large amounts of carbon. When they die they transport the carbon into the deep ocean where it provides a feast to many species, that are specialized. Therefore whales help to delay global warming!
Countries that still hunt whales like japan Norway and Iceland might think killing whales boosts the food available for us to eat. But as the numbers of whales declined – so did the numbers of krill and fish. Because they not only eat them they also keep them alive. In fact they help sustain the entire living system of the ocean
Whales have been slaughtered for over 200 years. They were killed as a challenge for brave adventurers, for their meat, industrial usage of their bone and oil. Commercial whaling caused reduction in the population 60 to 90 percent. Luckily international whale commission and save the whale movement stopped it. Unfortunately there are still countries who hunt whales (Japan, Norway and Iceland).
Nowadays fishing, cargo and cruise ships sail around every cm of the oceans. There are almost no rules where they are allowed to drive. Only 2 percent of the ocean is protected! So ships often disturb marine habitats and it occurs regularly that they strike a whal.e
In the antarctic they are even fishing krill to make krill oil which is a serious threat to the ecosystem and whales. Fishing nets are able to catch fish in the deep sea where most of it is not even explored. Many species are caught as by catch which they throw dead back into the ocean. Another threat is noise pollution.
However still scientists need to understand the true and entire ecosystem value of these creatures. So we should save the whales not just for their sake but also ours!
Here are some images I took in Australia where I got the special opportunty to swim with humpack whales. I am very grateful for this day and it really gave me an awe for the wonderful life on this planet.
Wale sanfte Riesen der Meere Soury, Gerad 2008, Whale Wikipedia, Whale facts and information National Geographic, Whale species WWF
Youtube: Ted Why are Blue Whales so enormous Asha de Vos, How Whales change the climate Sustainable Human