Large Pleistocene Carnivores Kept Megaherbivore Populations in Check

A brand new study suggests large packs of big carnivores kept populations of megaherbivores in check during the Pleistocene.  This finding seems like a no-brainer, but some paleoecologists believe megaherbivores suffered little mortality attributable to predation and were instead limited by the availability of plant resources.  The results of this study imply that large carnivore predation of megaherbivores was beneficial for the environment as a whole.  Lowering the overall population of megaherbivores prevented the landscape from being denuded and protected vegetated habitats for birds and other small animals.

The authors of this study compared tooth size and shoulder height between large Pleistocene carnivores and modern carnivores.  They determined that Pleistocene carnivores were on average 50%-100% larger than modern day carnivores.  This greater size gave them the ability to better prey on megaherbivores.  Even though these carnivores were larger, they likely needed to hunt in packs to take down such megaherbivores as mammoth, mastodon, and ground sloth.

Elephant survives attack by 14 Lions

Lions attacking a juvenile elephant.  A brand new study suggests Pleistocene carnivores in large packs regularly killed juvenile megaherbivores, keeping their populations in check so they didn’t destroy their environments.  Lions jump on the backs of baby elephants while other members of the pride chew through the tendons.  Incidentally, this individual eventually escaped.

The authors of this study also looked at modern incidences of predation on megaherbivores.  They noted that lions killed 74 elephants in Botswana over a 6 year period.  60% of these elephants were under 9 years old–evidence juveniles were easier to kill.  Lions killed 49 elephants over a 6 year period in Zimbabwe.  16% of black rhinos under the age of 2 were killed by lions or hyenas.  Hyenas killed 5 juvenile elephants in Hrange National Park, Kenya in 1 year.

Early European explorers reported much larger prides of African lions than are found there today.  Some saw prides of 40 lions in sparsely populated areas of Africa.  The authors of this study infer Pleistocene carnivores roamed the range in groups this large.  This may be true for American lions (Panthera atrox) and dire wolves (Canis dirus), but I’m of the opinion that saber-tooths (Smilodon fatalis) were for the most part solitary predators, though mothers with nearly full-grown cubs likely did gang attack juvenile megaherbivores.  Their specially evolved canines were an adaptation to slicing through thick-skinned necks.

Reference:

Valkenburgh, Blaire; et. al.

“Large Violent Animal Attacks Shaped the Ecosystems of the Pleistocene Epoch”

PNAS October 2015

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2 Responses to “Large Pleistocene Carnivores Kept Megaherbivore Populations in Check”

  1. George Crawford Says:

    Reblogged this on BLACKWATER DRAW LOCALITY 1.

  2. markgelbart Says:

    Thanks.

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