Every single living creature on this planet needs sleep, but for some creatures like birds, they have to sleep, holding on branches or other places. Has anyone ever fallen asleep while reading a book and then found the book on the ground when they wake up, they know the struggle of holding something while sleeping? So how do birds easily hold branches while sleeping?
How do birds easily hold branches while sleeping?
Not every bird can hold the branch while sleeping; the birds who hold the branches are known as Perching birds. These birds also have a tendon in between their feet. They have a pair of tendons in the back, flexor hallucis longus, and flexor digitorum longus. They are connected with the deep flexor muscles in their legs. The digitorum is responsible for working on the bird’s toes, while the hallucis is responsible for the working of back toes. Both the tendons extend to the ankle, and when the bird is reaching the land; the ankle bends, this makes both the tendons to pull up and making toes clench closer. Till the time the ankle is bent, the toes and tendons are stuck to one place. This is how birds can hold on to branches or other areas while sleeping.
Discovery of a new technique
Not every bird species have this feature except the Perching bird. Those birds who don’t have this feature to hold on to things are forced to sleep on land. Some birds have developed a technique of sleeping with one eye open. This is called unihemispheric slow-wave sleep or USWS, in which some birds, e.g., mallard ducks, can keep their half brain alerted and one eye open while allowing the second half to sleep. Researchers also claim that birds can control the USWS feature, and during this time, they feel completely safe. They can give their whole brain the required rest.