Please enable JavaScript.

Coggle requires JavaScript to display documents.

The Timeline of Bears - Coggle Diagram

- - - - Common Ancestor
        Raccoons, Bears, and Seals
        40 MYA
        
        Ursavus
        17.5 MYA
        
        Ursinae
        Bears
        1.25 MYA
        
        Ursus Arctos
        Brown Bear
        500 KYA
        
        Ursus Maritimus
        Polar Bear
        150 KYA
        
        Present
        
        Extensive debate exists on the speciation of polar bears. With estimates ranging from 5 MYA to 150 KYA.
        
        Ursus maritimus
        Polar Bear
        120 KYA
        Svalbard
        
        Liu et al. (2014)
        
        As a result of their environment, polar bears are the most carnivorous of the living bears.
        
        Due to the fact that polar bears are descended from brown bears, hybridization can occur. This results in the pizzly or grolar bear. This has been observed both in the wild and in captivity.
        
        Ursus arctos
        Brown Bear
        500 KYA
        Zhoukoudian
        
        Expanded into Europe and Africa 250 KYA
        
        McLellan, B., Reiner D. (1994)
        
        Ursus spelaeus
        Cave Bear
        1.2 MYA
        France
        
        Bears got big
        
        Basically unseen in regions without caves
        
        McLellan, B., Reiner D. (1994)
        
        Ailuropodinae
        Giant Panda
        3 MYA
        
        Ailuropoda melanoleuca
        Giant Panda
        
        Poor fossil record and disputed lineage, particularly as related to raccoons.
        
        Genetic analysis pegs pandas firmly as a subspecies of bear, their closeness to raccoons is remarkable however.
        
        O'Brien et al. (1985)
        
        Ailuropoda microta
        2 MYA
        Guangxi
        
        Much smaller than great pandas
        
        Distant Cousins
        Though the giant panda is from 3 MYA, their ancestors' divergence from mainline bears began nearly 15 MYA. Thus pandas are the most estranged living members of the bear family.
        
        Ursavus tedforti
        8 MA
        China
        
        The genus that beget modern bears but itself went extinct.
        
        Tremarctinae
        Short Faced Bears
        12 MA
        
        Bears that crossed the Panamanian isthmus into North America
        
        Largely extinct bar the spectacled bear of South America
        
        McLellan, B., Reiner D. (1994)
        
        Between a cat and wolf in size
        
        McLellan, B., Reiner D. (1994)
        
        Nine species of ursavus have been identified
        
        Ursavus elmensis, the dawn bear, is the oldest of the genus and what we would consider to be the first bear.
        
        What we see as bears develop is that they are increasing in size and their dentition is changing. Wolves have the teeth of a carnivore, whereas at this point bears begin moving towards an omnivoric existence.
        
        Seals
        27 MYA
      - Dogs
        35 MYA