Join our zoo community

Steller's sea cow had two populations c.1,000 years ago

Discussion in 'Wildlife & Nature Conservation' started by Surroundx, 2 Dec 2014.

  1. Surroundx

    Surroundx Well-Known Member

    Joined:
    3 Oct 2010
    Posts:
    598
    Location:
    Two Rocks, West Australia
    Rewriting the history of an extinction—was a population of Steller's sea cows (Hydrodamalis gigas) at St Lawrence Island also driven to extinction?

    Abstract

    The Kommandorskiye Islands population of Steller's sea cow (Hydrodamalis gigas) was extirpated ca 1768 CE. Until now, Steller's sea cow was thought to be restricted in historic times to Bering and Copper Islands, Russia, with other records in the last millennium from the western Aleutian Islands. However, Steller's sea cow bone has been obtained by the authors from St Lawrence Island, Alaska, which is significantly further north. Bone identity was verified using analysis of mitochondrial DNA. The nitrogen-15 (δ15N)/carbon-13 (δ13C) values for bone samples from St Lawrence Island were significantly (p ≤ 0.05) different from Bering Island samples, indicating a second population. Bone samples were dated to between 1030 and 1150 BP (approx. 800–920 CE). The samples date from close to the beginning of the mediaeval warm period, which could indicate that the population at St Lawrence Island was driven to extinction by climate change. A warming of the climate in the area may have changed the availability of kelp; alternatively or in addition, the animals may have been driven to extinction by the expansion of the Inuit from the Bering Strait region, possibly due to opening waterways, maybe following bowhead whales (Balaena mysticetus), or searching for iron and copper. This study provides evidence for a previously unknown population of sea cows in the North Pacific within the past 1000 years and a second Steller's sea cow extirpation event in recent history.

    Source:

    Crerar, Lorelei D. et al. (2014). Rewriting the history of an extinction—was a population of Steller's sea cows (Hydrodamalis gigas) at St Lawrence Island also driven to extinction? Biology Letters 10(11): 20140878. [Abstract]
     
  2. vogelcommando

    vogelcommando Well-Known Member

    Joined:
    10 Dec 2012
    Posts:
    12,089
    Location:
    fijnaart, the netherlands
    Very intresting stuff ! Thanks for sharing .
     
  3. TeaLovingDave

    TeaLovingDave Moderator Staff Member

    Joined:
    16 May 2010
    Posts:
    6,675
    Location:
    Wilds of Northumberland
    The really interesting thing about the taxon is that up until the expansion of man into those areas, it had pretty much the same range as the Sea Otter - being found as far south as California and Japan.