Shift in diet allowed gray wolves to survive ice-age mass extinction


Date:
April 12, 2021
Source:
Canadian Museum of Nature
Summary:
Gray wolves are among the largest predators to have survived the
extinction at the end of the last ice age. A new study analysing
teeth and bones shows that the wolves may have survived by adapting
their diet over thousands of years --- from a primary reliance on
horses during the Pleistocene, to caribou and moose today.



FULL STORY ==========================================================================
Gray wolves are among the largest predators to have survived the
extinction at the end of the last ice age around11,700 years ago. Today,
they can be found roaming Yukon's boreal forest and tundra, with caribou
and moose as their main sources of food.


==========================================================================
A new study led by the Canadian Museum of Nature shows that wolves may
have survived by adapting their diet over thousands of years -- from
a primary reliance on horses during the Pleistocene, to caribou and
moose today. The results are published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

The research team, led by museum palaeontologist Dr. Danielle Fraser
and student Zoe Landry, analysed evidence preserved in teeth and bones
from skulls of both ancient (50,000 to 26,000 years ago) and modern gray wolves. All the specimens were collected in Yukon, a region that once
supported the Beringia mammoth-steppe ecosystem, and are curated in the museum's national collections as well as those of the Yukon government.

"We can study the change in diet by examining wear patterns on the
teeth and chemical traces in the wolf bones," says Landry, the lead
author who completed the work as a Carleton University student under
Fraser's supervision. "These can tell us a lot about how the animal ate,
and what the animal was eating throughout its life, up until about a few
weeks before it died." Landry and Fraser relied on established models
that can determine an animal's eating behaviour by examining microscopic
wear patterns on its teeth. Scratch marks indicate the wolf would have
been consuming flesh, while the presence of pits would suggest chewing
and gnawing on bones, likely as a scavenger.

Analysis showed that scratch marks prevailed in both the ancient and
modern wolf teeth, meaning that the wolves continued to survive as
primary predators, hunting their prey.

What then were the gray wolves eating? The modern diet -- caribou and
moose - - is well established. The diet of the ancient wolves was assessed
by looking at the ratios of carbon and nitrogen isotopes extracted from collagen in the bones. Relative levels of the isotopes can be compared
with established indicators for specific species. "The axiom, you are
what you eat comes into play here," says Landry.

Results showed that horses, which went extinct during the Pleistocene, accounted for about half of the gray wolf diet. About 15% came from
caribou and Dall's sheep, with some mammoth mixed in. All this at a time
when the ancient wolves would have co-existed with other large predators
such as scimitar cats and short-faced bears. The eventual extinction of
these predators could have created more opportunity for the wolves to transition to new prey species.

"This is really a story of ice age survival and adaptation, and the
building up of a species towards the modern form in terms of ecological adaptation," notes Dr. Grant Zazula, study co-author, and Government
of Yukon paleontologist who is an expert on the ice-age animals that
populated Beringia.

The findings have implications for conservation today. "The gray wolves
showed flexibility in adapting to a changing climate and a shift in
habitat from a steppe ecosystem to boreal forest," explains Fraser. "And
their survival is closely linked to the survival of prey species that they
are able to eat." Given the reliance of modern gray wolves on caribou,
the study's authors suggest that the preservation of caribou populations
will be an important factor in maintaining a healthy wolf population.

========================================================================== Story Source: Materials provided by Canadian_Museum_of_Nature. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Zoe Landry, Sora Kim, Robin B. Trayler, Marisa Gilbert, Grant
Zazula,
John Southon, Danielle Fraser. Dietary reconstruction and evidence
of prey shifting in Pleistocene and recent gray wolves (Canis
lupus) from Yukon Territory. Palaeogeography, Palaeoclimatology,
Palaeoecology, 2021; 571: 110368 DOI: 10.1016/j.palaeo.2021.110368 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/04/210412084554.htm

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