As a whole there are around 90 known species of cetacea in existence today.
The cetacean family consists of all species of whale, dolphin and porpoises and is divided into two suborders which we refer to as the baleen whale and toothed whale suborders.
The larger baleen whale suborder is made up exclusively of large whales that possess baleen plates while the toothed whale suborder includes smaller toothed whales as well as dolphins and porpoises.
All three species are marine mammals and as mammals they all share several characteristics including:
- 1) Being warm-blooded – whales have a thick layer of blubber that helps insulate their internal organs and keep them warm in cold environments.
- Their blubber can also act as a source of energy when they are facing a food shortage or migrating.
- 2) Giving birth – whales go through a pregnancy/gestation period and give birth to their young just like land mammals.
- 3) Having hair – some species of whale are known to have body hair when they are first born, however the hair falls off shortly after birth.
- 4) Producing milk – Female whales produce milk from their mammary glands which they use to to feed their young.
- The baby whales will suckle the milk from their mothers nipple until they are able to hunt for their own food.
- 5) Breathing oxygen – Because whales are mammals they have lungs instead of gills so they must get their oxygen from the air above the water otherwise they would drown like all other mammals.
How warm-blooded whales survive in cold environments
When it comes to their survival in cold environments whales are very well adapted to thriving in this type of habitat.
Unlike humans whales are able to stay warm in extremely cold temperatures due to a thick layer of insulated blubber.
Depending on the whales species their blubber can be anywhere from 2 inches to over 1 ft. thick.
This thick layer of blubber allows the whale to maintain its body heat while preventing the cold temperature of the water from affecting its vital organs which allows the whale to swim around in the ocean comfortably, even in the coldest of temperatures.
The thickness of a whales blubber however doesn’t fully account for keeping it warm.
A whales lipid concentration can play an equally important role in maintaining the whales body heat.
A whale that has a high concentration of lipids in its blubber but has a thin layer of blubber for example may stay as warm as a whale with a thick layer of blubber and low concentration of lipids.
In addition to having a thick layer of blubber whales are also able to use their blubber for energy when they are unable to obtain food or when they travel to warmer environments where they may need to reduce their thick layer of blubber so they do not overheat.
Migration and climate change
During feeding season these marine mammals will stock up on large quantities of food and develop a thick layer of blubber in preparation for their migration trip.
Depending on where the whales live their feeding season may vary, but typically occurs during the warmer summer months.
While feeding these whales will consume excessive amounts of fish, krill, squid and any other type of food that is part of their primary diet.
When mating season comes around these whales migrate towards tropical climates to mate and some species may even forgo eating completely for several months while they travel to their breeding grounds.
By the end of the mating season these whales often end up losing a lot of energy and blubber, and will migrate back towards their feeding grounds to restore their supply of energy and blubber in preparation for the next mating season.
The losses these whales incur during their migration helps the whale to maintain a moderate body temperature during its time in and around the tropical climates.
Some species of whale have such a thick and dense layer of blubber that they can only travel so far before the heat begins to affect them and thus are unable to migrate as close to the equator as other species.
There are also some species of whale who stay in one climate zone all year around and do not migrate very far, so they may not need to use their blubber for energy the way a migrating whale species would.
For instance the bowhead whale inhibits the Arctic waters throughout year regardless of the season while the killer whale migrates in order to maintain its food supply rather than migrating for mating purposes.
Other survival factors
As stated earlier whales are marine mammals and are known for giving birth, producing milk and breathing air.
In addition to this whales that belong to the toothed whale family are equipped with echolocation which helps them maneuver through dark waters and look for nearby predators as well as identify potential sources of prey.
When hunting for food echolocation not only helps these marine mammals determine where a food source is but also helps the coordinate and orchestrate their attacks when hunting in groups.
By being able to figure out where other hunting partners are they can determine the best way to trap their prey, immobilize them and prevent them from escaping.
New research also points to the potential of echolocation existing among certain baleen whale species, however more data needs to be collected on this topic before a conclusion can be determined.
While the presence of echolocation isn’t well understood among baleen whales they are also able to defend themselves from potential predators due to their massive size and thick layer of blubber which can provide a defense against small predators.
In fact the only predators to the largest of the baleen whales is a pack of killer whales and these attacks are rare with the chances of successfully killing a giant baleen whale being even more rare.