Here’s a Look Into How Whales Sleep

The Fascinating Sleep Habits of Whales

Whales and dolphins have long captivated humankind, but our planet’s biggest animals still retain some mystery about how and when they sleep. Here, we take a deep dive into the world of cetacean sleep patterns.

Unihemispheric Slow Wave Sleep

First of all, whales, dolphins, and porpoises are collectively known as cetaceans, mammals (not fish) that breathe oxygen through blowholes on the top of their heads. While all species of cetaceans sleep, the amount of sleep needed and the sleeping behaviors vary from species to species. Unlike humans, whales and dolphins are not involuntary breathers; this means they have to consciously think about every breath they take – even while sleeping.

A Unique Solution

Whales have solved this problem of simultaneously being able to breathe and sleep by something called unihemispheric slow wave sleep. This means that one half of their brain is active as the other half rests. They even close one eye while the other remains alert, quite literally sleeping with one eye open. This behavior is thought to allow breathing, predator avoidance, swimming, and social behaviors all while one-half of the brain is resting.

Where and How Whales Sleep

Where and How Whales Sleep

In the wild, whales are usually observed sleeping horizontally close to the surface of the water. However, sperm whales are able to enter a deeper state of sleep, where they rest vertically, drifting just under the water surface in groups for around 10 to 15 minutes at a time. Researchers noted that they did not breathe or move at all during these whale power naps. Living life in the ocean has unexpected impacts on sleeping too; humpback whales are observed sleeping horizontally at the surface of the water for around 30 minutes. However, they cannot rest for longer than that because they would lose too much body heat by being inactive.

Whale Calves

Whale Calves

Whale calves can rest while their mothers swim, towing them along behind in a placement called echelon swimming. It has even been found that for the first month after birth, in killer whales and bottlenose dolphins, the mothers and calves will forgo sleep for a month and keep mobile 24 hours a day. This is likely linked to the same reason humpback whales sleep for a short amount of time, as the calves do not have the blubber to keep themselves warm during a prolonged resting period. The team found that after several months the killer whale calves were resting a similar amount to the adults.

A New Method for Generating Lost Cells Helps Blind Mice to See Again

A New Method for Generating Lost Cells Helps Blind Mice to See Again

MD, or age-related macular degeneration, is a wide range of ocular diseases that affect so many people, it’s downright described as nothing more than a process of aging.

How a Blind Person Can See Again

The study of MD has also proven itself to be useful for understanding how aging works as a whole. In an attempt to repair the damage to eyes and restore them back to a youthful and normal state, MD has quickly become one of the first places that scientists have looked into. In a new paper published online, researchers demonstrate an alternative to stem cells by creating photoreceptors from skin fibroblast cells. It’s a process that promises to be faster, more affordable, and unburdened by any legal or ethical restrictions.

Containing the generic code for every protein people need to repair or build cells, DNA can become damaged over time because of a stressful way of life. Just the way cracks and scratches on a CD prevent lasers from reading the information on it, damaged DNA becomes difficult, and in some cases, even impossible for our RNA to read the genetic information contained therein.

A New Method for Generating Lost Cells Helps Blind Mice to See Again

Ph. D. Sai Chavala says that the photoreceptors are the neurons in the eye that turn on visual circuity in response to light that enables us to have vision. The loss of photoreceptors can result in MD and other retinal diseases. They can cause a person to become irreversibly blind. In a study, however, cells called fibroblasts can be reprogrammed to reproduce cells that are similar to photoreceptors. They’re shown to restore the vision of mice.

Blind Mice

Sai Chavala and colleagues from the Center for Retina Innovation in Dallas, Texas, discovered a set of compounds that can drive embryonic fibroblast cells to convert themselves into rod-like retinal photoreceptors in both human and mice cells. Dr. Chavala says that stem cell-based strategies are extremely exciting but also adds that generating them can be time-consuming and cumbersome.

These conversions of fibroblasts to photoreceptors have also been done in humans. Dr. Chavala explained that he believes treatments and future research will spring from this discovery.