By Jennie LiuModern Animal - BeaversExtinct Animal - The Giant Beaver


Beaverines are a type of marine mammal. Other types of marine mammals include Blue whales, Killer whales, polar bears, dolphins etc. Beaverines require oxygen and can only stay under water for around 20-30 minutes. Therefore, they must swim to the surface of the water once in a while to breath similar to whales. Beaverines evolved from beavers but are a little smaller than beavers. Unlike beavers, Beaverines do not have any fur and do not go on land. Beaverines are around 50 - 60 cm in length and weigh 18-20 kg. So they are very small animals.


Areas of the World it lives in:


Fig 1: Area of the world beaverines live in (circled in white)

Beaverines are found in the lakes, rivers and seas of a few countries in North America and parts of Asia. The numbers of beaverines have decreased a lot due to the pollution of lakes and rivers. In North America they are only found in the colder areas of Canada and Alaska because the climate is still suitable for Beaverines. Beaverines are extinct in the United States due to the large amount of illegal poaching for beaverine’s glands. Due to the effects of global warming and change in climate in countries, Beaverines have died out in the warmer countries such as Mexico and Florida. A very small amount of Beaverines can still be found in other countries of North America. Beaverines have been introduced to areas of Asia but only small amounts are left because of the contamination of Beaverines’ habitat. In the poorer countries of Asia, the habitats of Beaverines have been completely destroyed due to the disposal of toxic waste, plastic bags and other chemicals that kills Beaverines.

Preys & Predators:

Beaverines have evolved to become carnivores meaning that they eat meat. Beaverines that live in seas usually feed on small fish, shrimps, seaweed and sea plants. While beaverines that live in rivers and lakes feed on twigs and branches that have fallen from nearby trees, small fish and pondweed.

Unlike the ancient beavers, Beaverines do not have any land predators since they are marine mammals. Like beavers, Beaverines are also preys. Beaverines that live in lakes and rivers are almost safe from any predators as most of the living aquatic organisms around them are smaller and more vulnerable than Beaverines. However, Beaverines that live in seas have quite a few predators including whales, sharks and large fish.


Beaverines are usually found in colder regions. Beaverines cannot live in tropical, hot or humid waters. Global warming many millions of years ago has caused many beaverines to become extinct, as many of their natural habitats’ climates have changed a lot warmer. They will also die if the waters of their habitat are freezing cold, as Beaverines have not evolved to protection for extreme cold. So beavers must live in waters that are very cold but not freezing. Therefore, the water temperature of Beaverine’s habitat must be exactly right and a slight change in the water temperatures, either colder or warmer, can wipe out Beaverines to extinction.

Type of Waters:

Beaverines have become evolved to live in waters that are polluted. Beaverines are able to survive and live in waters that are polluted by a small amount of rubbish. Wastes such as human food waste, feces and urine do not affect Beaverines. However toxic waste and chemicals can kill Beaverines. Most beaverines live seas, rivers and lakes that are a little polluted, as clean seas, rivers and lakes are rare.



Fig 2: Diagram of Adaptations of Beverine

Fig 3: Sketch of Beaverine

Physiological – Resting

Like whales, Beaverines do not sleep at all but rest a lot from time to time and are never fully asleep. When Beaverines rest, one hemisphere of the brain sleeps while the other is awake. When one hemisphere of the brain is awake, they are still conscious and aware of its surroundings and the things going on around them. Resting frequently allows them to stay energetic and to restrain Beaverines from being too tired. It also prevents Beaverines from drowning. Ancient beavers slept but when they evolved into Beaverines they became fully aquatic but still required oxygen. In order to rest their brains but not drown from an insufficient amount of oxygen, they must only rest and cannot be unconscious. Therefore, Beaverines evolved to have only one hemisphere of the brain sleeping and the other awake.

Structural – Good Insulation

Since Beaverines have no fur (this adaptation is explained below), they have a thick layer of fat under their skin. Beaverines' layer of fat is normally around 3-5 cm thick. The thick layer of fat is for insulation and keeps them warm during the winters. This feature evolved millions of years ago when humans polluted the original habitats of the ancient beavers and they were forced by extreme pollution to leave their original warm habitat and to live in a less polluted area that was very cold. This layer of fat is not thick enough to allow beaverines to live in freezing waters and this accounts for why beavers can live in cold but not freezing waters.

Structural – No Fur

Unlike their ancestors, Beaverines do not have any fur at all. This decreases their body weight thus allowing them to swim faster and more freely in the water. Moving faster in water makes it easier for them to swim away from fast predators and reduces the likelihood of getting captured by their predators. The environmental pressure that led to this is that all the predators of Beaverines are very fast swimmers and in order to survive, Beaverines evolved to have no fur.

Structural – Unique Nostrils

Beaverines have nostrils that are very similar to blowholes of cetaceans. Beaverines’ nostrils have a muscular flap that closes and contracts when they are underwater and opens when they come up the water to breathe. Beaverine’s unique nostrils allow them to breathe and not suffocate to death and it also prevents water from entering the nostrils and choking the beaverines. When beaverines turned into fully aquatic animals, they still required oxygen. However normal nostrils caused choking and a lot of inconvenience so in order for beaverines to survive as marine mammals, these unique nostrils were developed.

Structural – Brown Skin Colour

Beaverines have skins that are brownish gray with a few specks of dark gray. This colour and pattern is similar to the ones of seabed, riverbed and lakebed. The brownish gray is similar to the colour of the sand and the specks of dark gray are similar to the small rocks. This helps them camouflage and prevents predators from seeing them and capturing them. When beaverines first became fully aquatic animals, their predators easily spotted them as their fur had a colour that was very easily spotted in the water. Their predators are also very fast and it is quite difficult for Beaverines to swim away from them. So in order to survive in the new environment, beaverines evolved to have this skin colour so it is less likely for them to be eaten by their predators.

Selection Pressure

Pollution was one of the major factors that forced beavers to extinction. The habitats of beavers including rivers and lakes with warm water have been severely polluted with chemicals and toxic waste. As a result of this beavers were forced onto land but because beavers had many land predators many of them soon died. A few of the beavers that did not die found rivers, lakes and seas in cooler areas that were a lot cleaner and these beavers evolved to live in cold waters. However, once these beavers became fully adapted to cold waters, global warming forced these beavers to die too. The rivers and lakes in many of the cooler areas began to warm up and soon many of the beavers also died. The small amounts that survived evolved into beaverines after millions of years and migrated again to the cold waters.


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  2. How Stuff Works. (2011). How Animal Camouflage Works. Retrieved 25th June 2011, from
  3. Wikipedia. (2011). Marine Mammal. Retrieved 25th June 2011, from

Fig 1: Areas of the World Beaverines Live in (Asia and North America) - 2: Diagram of adaptation of Beverines - Drawn by Jennie LiuFig 3: Sketch of Beaverine - Sketched by Jennie Liu