Black Winged Stilt is seen on Kavak Delta, a natural and ecologically important wetland for many migratory birds, in Canakkale, Turkiye on May 13, 2025. (Photo by Alper Tuydes/Anadolu via Getty Images)
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.
Members of Myanmar's vovinam team warm up before competing in the vovinam event at the 32nd Southeast Asian Games (SEA Games) in Phnom Penh on May 6, 2023. (Photo by Mohd Rasfan/AFP Photo)
A fan watches the pre-game before an NFL football game between the Indianapolis Colts and the Tampa Bay Buccaneers Sunday, November 26, 2023, in Indianapolis. (Photo by Darron Cummings/AP Photo)
Breath at sunset, captures a sea turtle at a dive site called Black Rock. Kāʻanapali, Hawaiʻi, August 2013. (Photo by Christopher Doherty/Smithsonian.com)
Hungarian model Viktoria Varga stunned in a black dress early January 2024. The social media star visited Dubai on holiday. (Photo by vikyvarga/Instagram)