Nav: Home

Reconstructing the diet of fossil vertebrates

February 17, 2020

Information on what our ancestors ate is based mainly on carbon and nitrogen isotope analyses of the structural protein collagen in bones and dentin. Nitrogen isotope analysis, in particular, helps scientists determine whether animal or plant food was consumed. Since collagen, like proteins in general, is not easily conservable, this method cannot be used to examine vertebrate fossils older than about 100,000 years. This timeframe is even often reduced to only a few thousand years in arid or humid tropical regions like Africa and Asia, which are considered key regions for human evolution and are therefore of particular interest to science. New methods - such as zinc isotope analysis - are now starting to open up new research perspectives.

Zinc isotopes serve as indicators for food type consumed

The researchers analyzed the ratio of two different zinc isotopes in the dental enamel of fossil mammals that had only recently been discovered in a cave in Laos. These fossils date from the late Pleistocene, more precisely from around 13,500 to 38,400 years ago. In 2015, in the Tam Hay Marklot cave in northeastern Laos, scientists found fossils of various mammals, including water buffalos, rhinos, wild boars, deer, bears, orangutans and leopards. "The cave is located in a tropical region where organic materials such as collagen are generally poorly preserved. This makes it an ideal location for us to test whether we can determine the differences between herbivores and carnivores using zinc isotopes," says study leader Thomas Tütken, professor at the JGU's Institute of Geosciences.

First study with zinc isotopes on fossils shows preservation of food signatures

Zinc is ingested with food and stored as an essential trace element in the bioapatite, the mineral phase of tooth enamel. Thus, zinc has a better chance of being retained over longer periods of time than the collagen-bound nitrogen. The relevant ratio is derived from the ratio of zinc 66 to zinc 64: "On the basis of this ratio we can tell which animals are herbivores, carnivores or omnivores. This means that among the fossils we analyze, we can identify and clearly distinguish between carnivores and herbivores, while omnivores are expected to be in between," says Nicolas Bourgon first author of the study from the Max Planck Institute for Evolutionary Anthropology and PhD student in Tütken's research group. Lean meat contains more zinc-64 than plant food does. Carnivores, like the tiger, will have a smaller ratio of zinc-66 to zinc-64, as compared to herbivores, like the water buffalo.

In order to exclude alteration from external sources on the samples, the fossils were also examined by the team of Klaus Peter Jochum at the Max Planck Institute for Chemistry. No changes were found when comparing the concentration and distribution of zinc and other trace elements of fossil tooth enamel with those of modern animals using laser ablation ICP mass spectrometry.

Time horizon to be extended to over 100,000-year-old fossils

The zinc isotope method has now - for the first time - been successfully applied to fossils. "The zinc isotope ratios in fossil enamel from the Tam Hay Marklot cave suggest an excellent long-term conservation potential in enamel, even under tropical conditions," summarize the authors. Zinc isotopes could thus serve as a new tool to study the diet of fossil humans and other mammals. This would open a door to the study of prehistoric and geological periods well over 100,000 years ago. In the future, the next goals are to apply this method to reconstruct human dietary behaviours. The researchers also want to find out how far back in time back in time they can go, by applying their new method to fossils of extinct mammals and dinosaurs that are millions of years old.
-end-


Max Planck Institute for Evolutionary Anthropology

Related Zinc Articles:

A nanoscale laser made of gold and zinc oxide
Tiny particles composed of metals and semiconductors could serve as light sources in components of future optical computers, as they are able to precisely localize and extremely amplify incident laser light.
Zinc lozenges did not shorten the duration of colds
Administration of zinc acetate lozenges to common cold patients did not shorten colds in a randomized trial published in BMJ Open.
Dietary zinc protects against Streptococcus pneumoniae infection
Researchers have uncovered a crucial link between dietary zinc intake and protection against Streptococcus pneumoniae, the primary bacterial cause of pneumonia.
Zinc could help as non-antibiotic treatment for UTIs
New details about the role of zinc in our immune system could help the development of new non-antibiotic treatment strategies for bacterial diseases, such as urinary tract infections (UTIs).
Zinc deficiency may play a role in high blood pressure
Lower-than-normal zinc levels may contribute to high blood pressure (hypertension) by altering the way the kidneys handle sodium.
Genetic polymorphisms and zinc status
Zinc is an essential component for all living organisms, representing the second most abundant trace element, after iron.
Autism is associated with zinc deficiency in early development -- now a study links the two
Autism has been associated with zinc deficiency in infancy. While it is not yet known whether zinc deficiency in early development causes autism, scientists have now found a mechanistic link.
Can chocolate, tea, coffee and zinc help make you more healthy?
Ageing and a low life expectancy are caused, at least partly, by oxidative stress.
Zinc oxide nanoparticles: Therapeutic benefits and toxicological hazards
Despite the widespread application of zinc oxide nanoparticles in biomedicine, their use is still a controversial issue.
Preconception zinc deficiency could spell bad news for fertility
The availability of micronutrients in the ovarian environment and their influence on the development, viability and quality of egg cells is the focus of a growing area of research.
More Zinc News and Zinc Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at Radiolab.org/donate.