Did you know that whales and dolphins sleep vertically, with half their brain still active to alert for predators and keep their tail moving so that they won’t drown? Since they evolved from land mammals, they need to breathe air to get oxygen just like us and to do that, they have to surface above the water regularly. The world is full of fascinating facts and surprising stories such as this that are just waiting to be discovered. Here are ten such random facts about the world that will help you kill some time.
1. Owls have tube-shaped eyes rather than spherical ones, and they cannot roll or rotate their eyes. To compensate for it, they have evolved the ability to rotate their heads 270° in either direction.
One of the many unique features of owls is that unlike the rest of the birds, their eyes are placed at the front of their heads rather than on either side, which gives them some of the largest binocular fields of vision. They are one of the few nocturnal birds that do not use echolocation during the night. Instead, their eyes are disproportionately large, making up to 3% of their body weight compared to human eyes which are just 0.0003% of our body weight.
Since the large eyes have to be housed in a relatively small skull, they have evolved to be tubular, held tightly in place by a set of bones known as “sclerotic rings.” Instead of rotating their eyes, they can rotate their heads 270° in either direction and 90° up and down. With one advantage comes one disadvantage. The owls are farsighted, which means though they can see with crystal clarity what’s far away, they have trouble focusing on what’s nearby. They have to rely on sensitive, whisker-like bristles to sense objects up close. (1, 2)
2. Most birds need gravity to swallow water.
When we drink water, our esophagus undergoes a mechanism known as “peristalsis” which creates a contracting and expanding motion that travels like a wave down the tube moving water and food to our stomach. Birds cannot do this. They generally drink water by lapping it up with their tongue like other animals or gathering it in their beaks and then tilting their head back to let it flow down to their stomach.
There are very few exceptions to this, like pigeons and doves that can suck water even with their heads bent down, or pelicans which collect rainwater in their large beaks. Some birds, especially those living in deserts, do not usually drink water at all. Hummingbirds make do with the nectar which they use their tongue to encircle and pump down their throat. (1, 2)
3. Mushrooms are more genetically related to humans than they are to plants.
Mushrooms, along with yeasts and molds, belong to a group of eukaryotic organisms that we know as fungus. Considering how they do not move or react, for a long time, fungi were considered a part of the plant kingdom and were not given the status of one of the five kingdoms of life until the advent of molecular biology. Now we know that their evolution diverged from other life over one billion years ago, and though they are unique, they share many genetic features with animals.
What sets them apart from plants is their cell walls which contain a long-chain polymer called “chitin,” also found in the exoskeletons of insects, arthropods, mollusks, crustaceans, cephalopods, and even in the scales of fish. A more apparent distinction from plants is that fungi do not perform photosynthesis to make their own food. Instead, just like animals, they absorb dissolved molecules by secreting digestive enzymes on existing organic matter. Another common feature with animals is the presence of lanosterol, a compound both animals and fungi use to derive steroids and eventually cholesterol. (1, 2)
4. The terminal velocity of an ant is around 3.9 mph.
When an object is dropped from a height, it begins to accelerate at 9.8 m/s2 towards the ground due to gravity. But the object also experiences air resistance or drag that pushes it upward. At a certain point, the gravity and the drag force become equal, canceling acceleration and causing the object to fall at a constant velocity known as “terminal velocity.” The terminal velocity depends on two things – how heavy the object is and how wide the object’s horizontal cross-section area is.
Ants might be ubiquitous creatures on Earth contributing an estimated 15–20% of terrestrial animal biomass. That’s more than all the vertebrates, but the weight of a single, average worker ant is just between 1-5 mg. So, its terminal velocity is just 3.9 mph (6 kph), and in comparison, for a human, it is 124 mph (200 kph). Also, for their size and mass, the ants have a very tough exoskeleton, and according to Michael Kaspari, an ecologist at the University of Oklahoma, they can use their legs to maneuver through the air and glide. So, they’re not in as much danger of getting hurt from a fall as we are. (1, 2, 3)
5. The consistency of a nursing sperm whale’s milk is that of cottage cheese so that the calf can just “eat it” in the water.
Being aquatic mammals, all species of whales must deliver and nurse their calves in water. That means suckling them in water too, and milk at the consistency produced by land mammals would just dissolve in the water. So, sperm whales, just like other whales, produce milk that has very high fat content, about 36% compared to 4% in cow milk, and an energy content of approximately 3,840 kcal/kg, while cow milk has just 640 kcal/kg. This gives the milk a consistency similar to cottage cheese or toothpaste that the calf can simply eat. Another important purpose of the high-fat content is to help develop blubber in the young. (1, 2)