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Rare leafcutter bee fossils reveal Ice Age environment at the La Brea Tar Pits

Date:
April 9, 2014
Source:
Natural History Museum of Los Angeles County
Summary:
The La Brea Tar Pits are celebrated for saber-toothed cats and mastodons. The site's insect collection is also of great significance. Recent examination of fossil leafcutter bee nest cells exemplifies how fossil insects reveal insights into the habitat and climate at the La Brea Tar Pits toward the last Ice Age.
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Concerns about climate change and its impact on the world around us are growing daily. New scientific studies at the La Brea Tar Pits are probing the link between climate warming and the evolution of Ice Age predators, attempting to predict how animals will respond to climate change today.

The La Brea Tar Pits are famous for the amazing array of Ice Age fossils found there, such as ground sloths, mammoths, and predators like saber-toothed cats and powerful dire wolves. But the climate during the end of the Ice Age (50,000-11,000 years ago) was unstable, with rapid warming and cooling. New research reported here has documented the impact of this climate change on La Brea predators for the first time.

Two new studies published by research associates at of the Page Museum document significant change over time in the skulls of both dire wolves and saber-toothed cats. "Different tar pits at La Brea accumulated at different times," said F. Robin O'Keefe of Marshall University, lead author on the dire wolf study. "When we compare fossils deposited at different times, we see big changes. We can actually watch evolution happening."

After the end of the last Ice Age, La Brea dire wolves became smaller and more graceful, adapting to take smaller prey as glaciers receded and climate warmed. This rapidly changing climate drove change in saber-toothed cats as well. "Saber-toothed cats show a clear correlation between climate and shape. Cats living after the end of the Ice Age are larger, and adapted to taking larger prey," said Julie Meachen of Des Moines University, lead author on the sabertooth study.

The two scientists discuss their work in a video here: http://www.youtube.com/watch?v=jK_DKSNbgR4&feature=youtu.be

"We can see animals adapting to a warming climate at La Brea," said O'Keefe. "Then humans show up and all the big ones disappear. We haven't been able to establish causality there yet. But we are working on it."

The emerging links between climate change and evolution needs further study. There are many unanswered questions; such as why predators change in the ways that they do, the importance of factors other than climate, and whether the arrival of humans played a role in the mass extinction at the end of the Ice Age. "There is much work to be done on the specimens from the tar pits. We are working actively to bring together the researchers and resources needed to expand on these discoveries," says John Harris, chief curator at the Page Museum. "Climate change is a pressing issue for all of us, and we must take advantage of what Rancho La Brea can teach us about how ecosystems react to it."


Story Source:

Materials provided by Natural History Museum of Los Angeles County. Note: Content may be edited for style and length.


Journal References:

  1. J. A. Meachen, F. R. O'Keefe, R. W. Sadleir. Evolution in the sabre-tooth cat,Smilodon fatalis, in response to Pleistocene climate change. Journal of Evolutionary Biology, 2014; 27 (4): 714 DOI: 10.1111/jeb.12340
  2. O'Keefe, F. R., W. J. Binder, S. R. Frost, R. W. Sadleir, and B. Van Valkenburgh. Cranial morphometrics of the dire wolf, Canis dirus, at Rancho La Brea: temporal variability and its links to nutrient stress and climate. Palaeontologia Electronica, 2014

Cite This Page:

Natural History Museum of Los Angeles County. "Rare leafcutter bee fossils reveal Ice Age environment at the La Brea Tar Pits." ScienceDaily. ScienceDaily, 9 April 2014. <www.sciencedaily.com/releases/2014/04/140409204421.htm>.
Natural History Museum of Los Angeles County. (2014, April 9). Rare leafcutter bee fossils reveal Ice Age environment at the La Brea Tar Pits. ScienceDaily. Retrieved March 19, 2024 from www.sciencedaily.com/releases/2014/04/140409204421.htm
Natural History Museum of Los Angeles County. "Rare leafcutter bee fossils reveal Ice Age environment at the La Brea Tar Pits." ScienceDaily. www.sciencedaily.com/releases/2014/04/140409204421.htm (accessed March 19, 2024).

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