Bonnie Morgan arrives at the LA Premiere of “Rings” at the Regal LA LIVE Stadium 14 on Thursday, February 2, 2017, in Los Angeles. (Photo by Willy Sanjuan/Invision/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.
Meet the real beach babes: the herd of pigs that live a life of luxury paddling in the crystal clear waters of the Bahamas, on August 28, 2013. (Photo by Caters News)
A monkey jumps from a branch at Yangon Zoological Gardens in Yangon, Myanmar, 06 April 2016. Yangon Zoological Gardens (Yangon Zoo) is the oldest and second largest zoo in Myanmar. (Photo by Lynn Bo Bo/EPA)
Two copper sharks ride the waves in Red Bluff Beach, Australia on July, 2020. Professional photographer Sean Scott, 43, from Burleigh Heads, Australia, caught the stunning snap. (Photo by Sean Scott/MediaDrumImages/@seanscottphotography)
A pod of white pelicans, one of the largest birds in Canada and the US, are seen on the shore of the Chapala lagoon in Cojumatlan de Regules, Mexico, on January 28, 2022. White pelicans travel thousands of kilometers migrating from the cold temperatures of North America. (Photo by Ulises Ruiz/AFP Photo)
Workers hang thousands of different colorful fabrics on iron wires tied between a bamboo framework and constantly turn them so that they dry perfectly in a flooded field in Narayanganj, Bangladesh on March 16, 2022. (Photo by Joy Saha/ZUMA Press Wire/Rex Features/Shutterstock)