Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Shrinking Sheep

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CLIMATE change has caused a flock of wild sheep on a remote northern Scottish island to become smaller, according to an unusual investigation published on Thursday.  Read more here.

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  1. Helen Mahar says

    Unusual all right. Talk about jumping to the concluions you are looking for!

    Lots of environmental factors can lead to smaller sheep.
    1. Lack of feed for pregnant ewes = smaller lambs born
    2, Lack of supplementary feed for lambs = smaller lambs. They start nibling grass almost as soon and they are born.
    3 Lambs born into poor feed (eg droughts) often fail to reach their potential size.
    4 The ewes from these lambs, being smaller, also have smaller lambs. Takes two generations of good feed conditions to recover from this set back. eg note the increasing size of humans over the last 100 yeas in developed countries.
    5 Feed shortages can be caused by weather (been warming lately, grass should be better) or introduced pests. To claim that observed weight reductions of 85g/generation is natural evolution is stunning. Makes sheep breeders look a bit slack.

    Also, sheep have a natural cycle, timed to drop lambs in late spring, when feed conditions are best. In warm climates like Australia, sheep, especially merinos, can cycle all year round, but even these still get the best drop with spring lambing. A slightly warmer climate could result in a few of-season lambs in this study. Believe it’s been cooling lately up there…

    This sort of “science” creates doubt and scepticism in those who have information or experience against which to measure the claims.

    When looking for explanations of observations, always spin more than one hypothesis.

  2. Helen Mahar says

    Correction –
    5 been cooling lately – grass should be poorer.

    If it had been warming, as AGW theory proposes, then better feed conditions should have produced more robust sheep. Need to look for other expanations – or take another look at the data.

  3. SJT says

    Helen, do you think they are idiots who don’t consider all the factors you are talking about too?

    ““But now, due to climate change, grass for food is available for more months of the year and survival conditions are not so challenging – even the slower-growing sheep have a chance of making it, and this means smaller individuals are becoming increasingly prevalent in the population.””

    They were looking at all the factors you mentioned, and they didn’t add up. It was only when they considered climate change that it made sense. And they are talking about long term trends, not the year by year wiggles.

  6. spangled drongo says

    There is no mention of measured data to prove that their habitat was actually warmer.
    Maybe they are just going by the hockey stick thermometer or British weather forcasts or maybe they used a computer program.
    There is absolutely nothing happening in weather or climate to indicate a pattern of GW [other than normal variability] let alone enough to create an evolutionary change in an animal.
    But maybe it’s the same pattern that’s increasing polar bear numbers.
    Increasing numbers = younger average age = smaller average size.

  7. SJT says

    “Good for more funding, no doubt.”

    Usual line of insult. They were doing the research regardless of AGW, and had not been expecting any AGW affects on their area of study.

    The appeal to emotion on numberwatch is no sort of argument either. He appears to not understand that a global phenomenon will affect all areas of the globe. This is just one more area of the globe. It’s a big place. There will be a lot more stories to add to his list over the coming years.