Why Does Stomach Acid Vary in Animals?
Aug 04, 2025
Sean W. (age 11) asked,
“Why does stomach acid vary in strength from animal to animal?”
Thanks for your question, Sean.
Humans and animals have acid in their stomachs that serves many important functions, including breaking down food, protecting against infection, and helping our body absorb nutrients.
When God created the animal kinds during creation week, every animal was a plant eater. But after Adam and Eve disobeyed God, death became part of God’s once very good creation. Now some animals hunt each other for food.
Because of the different diets of animals, some creatures need to have more acidity (uh-SI-duh-tee) in their stomach than others. Animals that have higher levels of stomach acid include scavengers (animals that eat other dead animals, like vultures and raccoons) and carnivores (animals that eat mostly meat, like lions, tigers, and sharks). The acid in these animals’ stomachs help them to more quickly digest a diet that is high in protein.1
While munching on meat, scavengers and carnivores might consume large amounts of harmful bacteria (tiny living things that can cause illness). The acid in their stomachs also kills off these harmful bacteria, helping to keep the animal healthy.2
Herbivores (animals that eat mostly plants, including deer, sheep, and cows) don’t need high levels of stomach acid because plants tend to carry less harmful bacteria. Animals that eat plants are less likely to get sick from the things they eat.3
Isn’t it amazing how God designed animals with the ability to adapt and survive in our fallen world?
Did You Know?
Vultures have some of the most acidic stomachs of any animal.4 The high levels of acid in their stomachs keeps them healthy, even while eating dead things that contain dangerous bacteria.
Do you have a question about God’s Word or his world? Ask your parents to help you submit your question here. We’d love to hear from you!
Footnotes
- DeAnna E. Beasley, Amanda M. Koltz, Joanna E. Lambert, Noah Fierer, and Rob R. Dunn, “The Evolution of Stomach Acidity and Its Relevance to the Human Microbiome,” PloS One 10, no. 7 (July 2015): https://doi.org/10.1371/journal.pone.0134116.
- Beasley, Koltz, Lambert, Fierer, and Dunn, “The Evolution of Stomach Acid.”
- Beasley, Koltz, Lambert, Fierer, and Dunn, “The Evolution of Stomach Acid.”
- Robert R. Dunn, Katherine R. Amato, Elizabeth A. Archie, Mimi Arandjelovic, Alyssa N. Crittenden, and Lauren M. Nichols, “The Internal, External and Extended Microbiomes of Hominins,” Frontiers in Ecology and Evolution 8 (February 2020): fig. 1, http://dx.doi.org/10.3389/fevo.2020.00025.
