A horse at the Great Yorkshire Show in Harrogate, UK on July 9, 2025. The county show is expecting to attract 140,000 visitors over four days. (Photo by Andrew McCaren/London News Pictures)
A model holds a dog presenting a creation by Anthony Rubio during New York Fashion Week, in New York City, U.S., September 13, 2025. (Photo by Caitlin Ochs/Reuters)
A pelican investigates a fallen ketchup bottle outside a cafe in St James’s Park in London, England on October 9, 2025. The species has lived there for hundreds of years and remain a popular sight for visitors. Introduced in 1664 as a gift from the Russian ambassador, about 40 pelicans have since made the park their home. The bottle was safely retrieved from the pelican. (Photo by Stephen Chung/Alamy Live News)
A woman and her dog compete in the Paris Sausage Walk along the banks of the River Seine on Sunday, November 16, 2025. The event raises funds for the well-being and adoption of dachshunds. (Photo by Dimtitar Dilkoff/AFP Photo)
In this Wednesday, May 23, 2012 photograph, a young deer and a cat share a moment in Feench village near Jodhpur, Rajasthan state, India. (Photo by AP Photo)
In animals, yawning can serve as a warning signal. For example, Charles Darwin, in his book The Expression of the Emotions in Man and Animals, mentioned that baboons yawn to threaten their enemies, possibly by displaying large canine teeth. Similarly, Siamese fighting fish yawn only when they see a conspecific (same species) or their own mirror-image, and their yawn often accompanies aggressive attack. Guinea pigs also yawn in a display of dominance or anger, displaying their impressive incisor teeth. This is often accompanied by teeth chattering, purring and scent marking.